Merge

Crypto
WASM
TESTS

.github/workflows/ci.yml

@@ -0,0 +1,65 @@
+name: CI
+
+on:
+  push:
+    branches: [master]
+  pull_request:
+
+env:
+  CARGO_TERM_COLOR: always
+  # The example workspace config points the type-map build script at this file.
+  MTP_TYPE_MAPS: example-type-maps.yaml
+
+jobs:
+  fmt:
+    name: rustfmt
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@stable
+        with:
+          components: rustfmt
+      - run: cargo fmt --all --check
+
+  clippy:
+    name: clippy
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@stable
+        with:
+          components: clippy
+      - uses: Swatinem/rust-cache@v2
+      - run: cargo clippy --workspace --exclude mtp-wasm --all-targets --all-features -- -D warnings
+
+  test:
+    name: test
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@stable
+      - uses: Swatinem/rust-cache@v2
+      - run: cargo test --workspace --exclude mtp-wasm --all-features
+
+  wasm:
+    name: wasm build
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@stable
+        with:
+          targets: wasm32-unknown-unknown
+      - uses: Swatinem/rust-cache@v2
+      # The WebTransport bindings in web-sys are still gated behind this cfg.
+      - run: cargo build -p mtp-wasm --target wasm32-unknown-unknown
+        env:
+          RUSTFLAGS: --cfg=web_sys_unstable_apis
+
+  deny:
+    name: cargo-deny
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: EmbarkStudios/cargo-deny-action@v2
+        with:
+          command: check

.gitignore

@@ -1,4 +1,18 @@
 **target/
-**Cargo.lock
 *.pem
 *.key
+example-usage/dev-cert/
+
+# The root Cargo.lock and the example-usage workspace lockfile are committed:
+# the workspace ships binaries (example-usage/*) and a committed lockfile keeps
+# their builds reproducible. Workspace members do not own a lockfile (the root
+# one governs them); ignore any stray per-member lockfiles so they are not
+# committed by accident.
+/client/Cargo.lock
+/codec/Cargo.lock
+/common/Cargo.lock
+/crypto/Cargo.lock
+/host/Cargo.lock
+/transport/Cargo.lock
+/type-map/Cargo.lock
+/wasm/Cargo.lock

Cargo.toml

@@ -9,6 +9,24 @@ members = [
     "client",
     "wasm",
 ]
+# `wasm` is a wasm32-only crate: it relies on web-sys unstable APIs
+# (`--cfg=web_sys_unstable_apis`, set in wasm/.cargo/config.toml) and the
+# wasm32 target. Cargo only reads .cargo/config.toml from the invocation
+# directory and its ancestors, so building it for the host target from the
+# workspace root fails. Exclude it from the default set so a bare
+# `cargo build`/`test`/`clippy` at the root matches CI, which always uses
+# `--exclude mtp-wasm`. Build it explicitly with:
+#   cargo build -p mtp-wasm --target wasm32-unknown-unknown
+default-members = [
+    ".",
+    "common",
+    "crypto",
+    "type-map",
+    "codec",
+    "transport",
+    "host",
+    "client",
+]
 resolver = "3"
 
 # =============================================================================

NATIVE-CLIENT.md

@@ -151,12 +151,12 @@ A `Keyring` bundles all secret and public key material for one identity:
 
 ```rust
 pub struct Keyring {
-    pub kem_secret_key: KemPrivateKey,
     pub kem_public_key: KemPublicKey,
-    pub sig_cl_secret_key: SignaturePrivateKey,   // Ed25519
+    pub kem_secret_key: KemPrivateKey,
-    pub sig_cl_public_key: SignaturePublicKey,    // Ed25519
-    pub sig_pq_secret_key: SignaturePqPrivateKey, // ML-DSA-65
     pub sig_pq_public_key: SignaturePqPublicKey,  // ML-DSA-65
+    pub sig_pq_secret_key: SignaturePqPrivateKey,
+    pub sig_cl_public_key: SignaturePublicKey,    // Ed25519
+    pub sig_cl_secret_key: SignaturePrivateKey,
 }
 ```
 
@@ -238,19 +238,24 @@ force-closes the QUIC connection if the peer has not already done so.
 ## Crypto Containers
 
 With the `crypto` feature, `DataValue` supports encrypted, signed, and
-signed+encrypted containers:
+signed+encrypted containers. Encryption uses ML-KEM to encapsulate to a
+recipient's KEM public key (from their `PublicKeyBundle`); only the holder of
+the matching `Keyring` can decrypt. Signing uses the sender's Ed25519 key.
 
 ```rust
-use mtp::crypto::{ChaCha20Poly1305, Ed25519Signer, SigAlgorithm};
+use mtp::crypto::{EncryptionType, Ed25519Signer, SigAlgorithm};
 
-let cipher = ChaCha20Poly1305::new(derive_encryption_key(...));
+let enc_type = EncryptionType::MlKemChaCha20Poly1305;
 let signer = Ed25519Signer::new(&keyring.sig_cl_secret_key)?;
 
+// `recipient` is the PublicKeyBundle of whoever should be able to decrypt
+// (e.g. the host's bundle, obtained out of band).
+
 // Encrypted container
 let mut enc = DataValue::Container(vec![
     (DataTypeId(1), DataValue::Str("secret".into())),
 ]);
-enc.encrypt_container(&cipher, b"aad");
+enc.encrypt_container(enc_type, &recipient, b"aad");
 
 // Signed container
 let mut sig = DataValue::Container(vec![
@@ -262,11 +267,18 @@ sig.sign_container(SigAlgorithm::ED25519, &signer);
 let mut sec = DataValue::Container(vec![
     (DataTypeId(1), DataValue::Str("both".into())),
 ]);
-sec.sign_and_encrypt_container(SigAlgorithm::ED25519, &signer, &cipher, b"aad");
+sec.sign_and_encrypt_container(SigAlgorithm::ED25519, &signer, enc_type, &recipient, b"aad");
 ```
 
-On the receiving side, use the corresponding `decrypt_into_container`,
+On the receiving side, the recipient decrypts with its own `Keyring` (each blob
-`verify_into_container`, or `decrypt_signed_encrypted_container` methods.
+is self-describing — its leading byte selects the algorithm and the matching KEM
+key from the keyring):
+
+```rust
+enc.decrypt_into_container(&keyring, b"aad");                // -> Container
+sig.verify_into_container(&verifier);                        // verifier: impl SignatureScheme
+sec.decrypt_signed_encrypted_container(&keyring, b"aad");    // -> SignedContainer, then verify_into_container
+```
 
 ## Policy Configuration
 
@@ -321,5 +333,3 @@ version and expects the host to negotiate a compatible version.
 | `AuthenticationFailed`  | Nonce mismatch or invalid host signature   |
 | `ConnectionError`       | QUIC connection failure                    |
 | `UseAfterClosed`        | Attempted send/receive after close         |
-
-

WASM-CLIENT.md

@@ -37,7 +37,7 @@ if (!WasmClient.is_supported()) {
 const config = new ConnectionConfig("https://host.example.com:4433");
 config.client_id = 12345n;                    // optional, for re-authentication
 config.server_certificate_hashes = [           // optional, for certificate pinning
-  "sha256:abc123...",
+  "sha-256:abc123...",
 ];
 ```
 
@@ -55,11 +55,12 @@ providing its hash:
 
 ```typescript
 config.server_certificate_hashes = [
-  "sha256:abcd1234...",  // hex-encoded hash value
+  "sha-256:abcd1234...",  // hex-encoded hash value
 ];
 ```
 
-The hash format is `"<algorithm>:<hex-encoded-hash>"`. When hashes are
+The hash format is `"<algorithm>:<hex-encoded-hash>"`, where the only algorithm
+the browser's WebTransport API currently accepts is `sha-256`. When hashes are
 provided, the browser **only** trusts certificates matching one of the given
 hashes and ignores its root store for this connection.
 
@@ -172,13 +173,16 @@ binary payload. Useful for health checks and simple messaging.
 function build_demo_message(
   clientId: bigint,
   keyringBytes: Uint8Array,
+  hostBundleBytes: Uint8Array,
 ): Uint8Array;
 ```
 
 Constructs a `Ping` frame that demonstrates encrypted, signed, and
-signed+encrypted containers using a deterministic demo key. The paired host
+signed+encrypted containers. The containers are ML-KEM-encrypted to the host's
-handler can decrypt and verify these containers if it knows the same shared
+`PublicKeyBundle` (`hostBundleBytes`, the same bytes passed to `auth_connect` /
-secret.
+`auth_register`), so the host decrypts them with its own keyring; signatures use
+the client keyring's Ed25519 key. The client keyring only needs its Ed25519
+signing key for this demo.
 
 ### `parse_auth_response`
 

client/src/lib.rs

@@ -2,6 +2,20 @@ use mtp_codec::{CommunicationValue, DataType, DataValue, PROTOCOL_VERSION, Versi
 use mtp_common::CommunicationError;
 use mtp_transport::{Policy, Receiver, Sender};
 
+#[cfg(feature = "crypto")]
+fn unexpected_response_type_error(
+    context: &str,
+    expected_type: mtp_codec::CommunicationTypeId,
+    response: &CommunicationValue,
+) -> CommunicationError {
+    CommunicationError::AuthenticationFailed(format!(
+        "unexpected response type during {context}: expected {:?}, got {:?}; parsed {}",
+        expected_type,
+        response.get_type(),
+        response
+    ))
+}
+
 pub struct ClientConfig {
     pub url: String,
     pub server_cert: Option<Vec<u8>>,
@@ -124,6 +138,15 @@ impl MTPClient {
 
         let tm = mtp_codec::TypeMap::latest();
 
+        let expected_type = mtp_codec::CommunicationType::IdentificationResponse.to_id(&tm);
+        if response.get_type() != expected_type {
+            return Err(unexpected_response_type_error(
+                "auth_connect",
+                expected_type,
+                &response,
+            ));
+        }
+
         let connected = response.get_data(DataType::Connected.to_id(&tm));
         match connected {
             DataValue::BoolTrue => {}
@@ -150,7 +173,7 @@ impl MTPClient {
         }
 
         let host_new_nonce = match response.get_data(DataType::Timestamp.to_id(&tm)) {
-            DataValue::UnsignedNumber(n) => *n as u128,
+            DataValue::UnsignedNumber(n) => *n,
             _ => {
                 return Err(CommunicationError::AuthenticationFailed(
                     "Missing new nonce".into(),
@@ -266,6 +289,15 @@ impl MTPClient {
 
         let tm = mtp_codec::TypeMap::latest();
 
+        let expected_type = mtp_codec::CommunicationType::RegisterResponse.to_id(&tm);
+        if response.get_type() != expected_type {
+            return Err(unexpected_response_type_error(
+                "auth_register",
+                expected_type,
+                &response,
+            ));
+        }
+
         let connected = response.get_data(DataType::Connected.to_id(&tm));
         match connected {
             DataValue::BoolTrue => {}
@@ -282,7 +314,7 @@ impl MTPClient {
         }
 
         let assigned_id = match response.get_data(DataType::Id.to_id(&tm)) {
-            DataValue::UnsignedNumber(n) => *n as u128,
+            DataValue::UnsignedNumber(n) => *n,
             _ => {
                 return Err(CommunicationError::AuthenticationFailed(
                     "Missing assigned ID".into(),
@@ -301,7 +333,7 @@ impl MTPClient {
         }
 
         let host_new_nonce = match response.get_data(DataType::Timestamp.to_id(&tm)) {
-            DataValue::UnsignedNumber(n) => *n as u128,
+            DataValue::UnsignedNumber(n) => *n,
             _ => {
                 return Err(CommunicationError::AuthenticationFailed(
                     "Missing new nonce".into(),

codec/src/communication_value.rs

@@ -324,8 +324,7 @@ impl CommunicationValue {
         #[cfg(feature = "crypto")]
         let frame_signature = if is_signed {
             let alg = cursor.read_u8().map_err(|_| CodecError::InvalidEncoding)?;
-            let sig_len =
+            let sig_len = SigAlgorithm::length(alg).ok_or(CodecError::InvalidEncoding)?;
-                SigAlgorithm::length(alg).ok_or(CodecError::InvalidEncoding)?;
             let mut sig = vec![0u8; sig_len];
             cursor
                 .read_exact(&mut sig)
@@ -389,11 +388,7 @@ impl CommunicationValue {
      * signature before the data payload.
      */
     #[cfg(feature = "crypto")]
-    pub fn sign_frame(
+    pub fn sign_frame(&mut self, algorithm: u8, signer: &impl SignatureScheme) -> Option<()> {
-        &mut self,
-        algorithm: u8,
-        signer: &impl SignatureScheme,
-    ) -> Option<()> {
         let signed_payload = self.build_signed_payload().ok()?;
         let sig = signer.sign(&signed_payload).ok()?;
         self.frame_signature = Some((algorithm, sig));

codec/src/data_value.rs

@@ -151,10 +151,17 @@ impl DataValue {
 
     const KIND_NULL: u8 = 0xFF;
 
+    /// Smallest possible encoded entry, used to cap pre-reservation when
+    /// decoding containers/arrays so a small frame cannot force a huge
+    /// allocation from an attacker-controlled count. A bool/null entry in a
+    /// container is 3 bytes (1 kind + 2 key); a bare value in an array is 1
+    /// byte, so 1 is the safe lower bound shared by both.
+    const MIN_ENTRY_BYTES: usize = 1;
+
     pub fn container_from_map(map: &BTreeMap<DataTypeId, DataValue>) -> DataValue {
         let mut container = Vec::new();
         for (key, value) in map {
-            container.push((key.clone(), value.clone()));
+            container.push((*key, value.clone()));
         }
         DataValue::Container(container)
     }
@@ -407,7 +414,7 @@ impl DataValue {
             DataValue::Container(c) => {
                 let mut out = BTreeMap::new();
                 for (k, v) in c {
-                    out.insert(k.clone(), v.clone());
+                    out.insert(*k, v.clone());
                 }
                 Some(out)
             }
@@ -452,7 +459,7 @@ impl DataValue {
             .map_err(|_| CodecError::InvalidEncoding)?;
 
         for (key, value) in entries {
-            Self::write_container_entry(&mut out, key.clone(), value)?;
+            Self::write_container_entry(&mut out, *key, value)?;
         }
         Ok(out)
     }
@@ -520,14 +527,11 @@ impl DataValue {
         match value {
             DataValue::BoolTrue => Ok(()),
             DataValue::BoolFalse => Ok(()),
+            #[allow(clippy::if_same_then_else)]
             DataValue::Bool(v) => {
                 // Kept intentionally: the kind marker already encodes the boolean,
                 // so both arms carry no payload. Retained for clear compatibility.
-                if *v {
+                if *v { Ok(()) } else { Ok(()) }
-                    Ok(())
-                } else {
-                    Ok(())
-                }
             }
             DataValue::SignedNumber(n) => {
                 buf.write_i128::<BigEndian>(*n)
@@ -607,7 +611,11 @@ impl DataValue {
 
     fn try_read_container(cursor: &mut Cursor<&[u8]>) -> Option<Self> {
         let count = cursor.read_u16::<BigEndian>().ok()? as usize;
-        let mut entries = Vec::with_capacity(count);
+        let remaining = cursor
+            .get_ref()
+            .len()
+            .saturating_sub(cursor.position() as usize);
+        let mut entries = Vec::with_capacity(count.min(remaining / Self::MIN_ENTRY_BYTES));
 
         for _ in 0..count {
             let kind = cursor.read_u8().ok()?;
@@ -653,7 +661,11 @@ impl DataValue {
 
     fn read_array(cursor: &mut Cursor<&[u8]>) -> Option<Self> {
         let count = cursor.read_u16::<BigEndian>().ok()? as usize;
-        let mut out = Vec::with_capacity(count);
+        let remaining = cursor
+            .get_ref()
+            .len()
+            .saturating_sub(cursor.position() as usize);
+        let mut out = Vec::with_capacity(count.min(remaining / Self::MIN_ENTRY_BYTES));
 
         for _ in 0..count {
             let kind = cursor.read_u8().ok()?;
@@ -1185,6 +1197,22 @@ mod tests {
         assert!(DataValue::from_bytes(&bytes[..0]).is_none());
     }
 
+    #[test]
+    fn test_oversized_count_does_not_overallocate() {
+        // A frame declaring 65535 entries but carrying almost no payload must be
+        // rejected without pre-reserving a Vec for 65535 entries. The capacity is
+        // capped against remaining bytes, so these decode attempts allocate at
+        // most a handful of slots before failing.
+        // Container path: count = 0xFFFF, no entries follow.
+        assert!(DataValue::from_bytes(&[0xFF, 0xFF]).is_none());
+        // Container path with one stray byte after the count.
+        assert!(DataValue::from_bytes(&[0xFF, 0xFF, 0x01]).is_none());
+        // Array path: force the container parse to fail first, then the array
+        // parse also sees the oversized count. A leading kind byte that is not a
+        // valid container entry makes try_read_container bail to the array path.
+        assert!(DataValue::from_bytes(&[0xFF, 0xFF, 0x08, 0xFF, 0xFF]).is_none());
+    }
+
     #[test]
     fn test_display_basic() {
         assert_eq!(format!("{}", DataValue::BoolTrue), "true");

codec/src/lib.rs

@@ -6,8 +6,8 @@ pub use data_value::{DataKind, DataValue};
 pub use mtp_common::CodecError;
 
 pub use mtp_type_map::{
-    communication_type_name, data_type_name, CommunicationType, CommunicationTypeId, DataType,
+    CommunicationType, CommunicationTypeId, DataType, DataTypeId, PROTOCOL_VERSION, TypeMap,
-    DataTypeId, TypeMap, Version, PROTOCOL_VERSION,
+    Version, communication_type_name, data_type_name,
 };
 
 pub(crate) fn rand_u32() -> u32 {

common/src/lib.rs

@@ -251,9 +251,18 @@ mod communication_error_tests {
 
     #[test]
     fn test_communication_error_display() {
-        assert_eq!(format!("{}", CommunicationError::UseAfterClosed), "Use after Closed");
+        assert_eq!(
-        assert_eq!(format!("{}", CommunicationError::StreamClosed), "Stream Closed");
+            format!("{}", CommunicationError::UseAfterClosed),
-        assert_eq!(format!("{}", CommunicationError::StreamError), "Stream Error");
+            "Use after Closed"
+        );
+        assert_eq!(
+            format!("{}", CommunicationError::StreamClosed),
+            "Stream Closed"
+        );
+        assert_eq!(
+            format!("{}", CommunicationError::StreamError),
+            "Stream Error"
+        );
     }
 
     #[test]

crypto/src/aead.rs

@@ -33,9 +33,9 @@ impl ChaCha20Poly1305 {
 #[cfg(feature = "chacha20poly1305")]
 impl AeadEncrypt for ChaCha20Poly1305 {
     fn encrypt(&self, plaintext: &[u8], aad: &[u8]) -> Result<Vec<u8>, CryptoError> {
-        use chacha20poly1305::aead::{Aead, KeyInit, Payload};
         use chacha20poly1305::XChaCha20Poly1305;
         use chacha20poly1305::XNonce;
+        use chacha20poly1305::aead::{Aead, KeyInit, Payload};
 
         let key = chacha20poly1305::Key::from_slice(&self.key);
         let cipher = XChaCha20Poly1305::new(key);
@@ -63,9 +63,9 @@ impl AeadEncrypt for ChaCha20Poly1305 {
 #[cfg(feature = "chacha20poly1305")]
 impl AeadDecrypt for ChaCha20Poly1305 {
     fn decrypt(&self, ciphertext: &[u8], aad: &[u8]) -> Result<Vec<u8>, CryptoError> {
-        use chacha20poly1305::aead::{Aead, KeyInit, Payload};
         use chacha20poly1305::XChaCha20Poly1305;
         use chacha20poly1305::XNonce;
+        use chacha20poly1305::aead::{Aead, KeyInit, Payload};
 
         if ciphertext.len() < 24 {
             return Err(CryptoError::InvalidNonceLength);
@@ -76,10 +76,7 @@ impl AeadDecrypt for ChaCha20Poly1305 {
         let cipher = XChaCha20Poly1305::new(key);
         let nonce_ref = XNonce::from_slice(nonce);
 
-        let payload = Payload {
+        let payload = Payload { msg: ct, aad };
-            msg: ct,
-            aad,
-        };
 
         cipher
             .decrypt(nonce_ref, payload)
@@ -109,9 +106,9 @@ impl Aes256Gcm {
 #[cfg(feature = "aes-gcm")]
 impl AeadEncrypt for Aes256Gcm {
     fn encrypt(&self, plaintext: &[u8], aad: &[u8]) -> Result<Vec<u8>, CryptoError> {
-        use aes_gcm::aead::{Aead, KeyInit, Payload};
         use aes_gcm::Aes256Gcm as AesGcmInner;
         use aes_gcm::Nonce;
+        use aes_gcm::aead::{Aead, KeyInit, Payload};
 
         let key = aes_gcm::Key::<AesGcmInner>::from_slice(&self.key);
         let cipher = AesGcmInner::new(key);
@@ -139,9 +136,9 @@ impl AeadEncrypt for Aes256Gcm {
 #[cfg(feature = "aes-gcm")]
 impl AeadDecrypt for Aes256Gcm {
     fn decrypt(&self, ciphertext: &[u8], aad: &[u8]) -> Result<Vec<u8>, CryptoError> {
-        use aes_gcm::aead::{Aead, KeyInit, Payload};
         use aes_gcm::Aes256Gcm as AesGcmInner;
         use aes_gcm::Nonce;
+        use aes_gcm::aead::{Aead, KeyInit, Payload};
 
         if ciphertext.len() < 12 {
             return Err(CryptoError::InvalidNonceLength);
@@ -152,10 +149,7 @@ impl AeadDecrypt for Aes256Gcm {
         let cipher = AesGcmInner::new(key);
         let nonce_ref = Nonce::from_slice(nonce);
 
-        let payload = Payload {
+        let payload = Payload { msg: ct, aad };
-            msg: ct,
-            aad,
-        };
 
         cipher
             .decrypt(nonce_ref, payload)

crypto/src/hash.rs

@@ -13,6 +13,12 @@ pub fn sha256_double(data: &[u8]) -> [u8; 32] {
 
 pub struct Sha256Hasher(sha2::Sha256);
 
+impl Default for Sha256Hasher {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 impl Sha256Hasher {
     pub fn new() -> Self {
         Self(sha2::Sha256::new())

crypto/src/helper.rs

@@ -196,5 +196,3 @@ pub fn decrypt_multi(
     }
     Err(CryptoError::DecryptionFailed)
 }
-
-

crypto/src/kem.rs

@@ -12,8 +12,7 @@ pub struct HybridKem;
 #[cfg(feature = "mlkem-tls")]
 impl HybridKem {
     pub fn generate_keypair() -> (KemPrivateKey, KemPublicKey) {
-        let (ek, dk) =
+        let (ek, dk) = mlkem_tls::X25519MlKem768::keygen(&mut rand_core::OsRng);
-            mlkem_tls::X25519MlKem768::keygen(&mut rand_core::OsRng);
         (
             KemPrivateKey::new(dk.as_bytes().to_vec()),
             KemPublicKey::new(ek.as_bytes().to_vec()),
@@ -23,8 +22,7 @@ impl HybridKem {
     pub fn encapsulate(recipient_pk: &KemPublicKey) -> Result<Encapsulated, CryptoError> {
         let ek = mlkem_tls::EncapsKey768::try_from(recipient_pk.as_bytes())
             .map_err(|_| CryptoError::KemEncapsulationFailed)?;
-        let (ct, ss) =
+        let (ct, ss) = mlkem_tls::X25519MlKem768::encapsulate(&ek, &mut rand_core::OsRng);
-            mlkem_tls::X25519MlKem768::encapsulate(&ek, &mut rand_core::OsRng);
         Ok(Encapsulated {
             ciphertext: ct.as_bytes().to_vec(),
             shared_secret: ss.as_bytes().to_vec(),

crypto/src/lib.rs

@@ -36,16 +36,16 @@ pub use aead::ChaCha20Poly1305;
 pub use aead::Aes256Gcm;
 
 #[cfg(feature = "ed25519-dalek")]
-pub use sign::{verify_ed25519, Ed25519Signer, SignatureScheme};
+pub use sign::{Ed25519Signer, SignatureScheme, verify_ed25519};
 
 #[cfg(feature = "ml-dsa")]
-pub use sign::{verify_ml_dsa, MlDsaSigner};
+pub use sign::{MlDsaSigner, verify_ml_dsa};
 
 #[cfg(all(feature = "ed25519-dalek", feature = "ml-dsa"))]
-pub use sign::{sign_dual, DualSignature};
+pub use sign::{DualSignature, sign_dual};
 
 #[cfg(feature = "sha2")]
-pub use hash::{sha256, sha256_double, Sha256Hasher};
+pub use hash::{Sha256Hasher, sha256, sha256_double};
 
 #[cfg(feature = "hkdf")]
 pub use kdf::{derive_encryption_key, hkdf_expand, hkdf_extract};
@@ -59,7 +59,7 @@ pub use enc::EncryptionType;
 pub use enc::{decrypt_with, encrypt_for};
 
 #[cfg(all(feature = "mlkem-tls", feature = "chacha20poly1305", feature = "hkdf"))]
-pub use helper::{decrypt_multi, encrypt_multi, MultiEncryptedMessage, RecipientEntry};
+pub use helper::{MultiEncryptedMessage, RecipientEntry, decrypt_multi, encrypt_multi};
 
 /* ================================ TESTS ================================ */
 #[cfg(test)]
@@ -148,12 +148,7 @@ mod tests {
         let (ed_signer, _, _) = Ed25519Signer::generate();
         let (ml_signer, _, _) = MlDsaSigner::generate();
         let dual = sign_dual(ed_signer.signing_key(), ml_signer.signing_key(), b"msg").unwrap();
-        dual
+        dual.verify(ed_signer.verifying_key(), ml_signer.verifying_key(), b"msg")
-            .verify(
-                ed_signer.verifying_key(),
-                ml_signer.verifying_key(),
-                b"msg",
-            )
             .unwrap();
     }
 
@@ -165,9 +160,14 @@ mod tests {
         let (ed_signer, _, _) = Ed25519Signer::generate();
         let (ml_signer, _, _) = MlDsaSigner::generate();
         let dual = sign_dual(ed_signer.signing_key(), ml_signer.signing_key(), b"msg").unwrap();
-        assert!(dual
+        assert!(
-            .verify(ed_signer.verifying_key(), ml_signer.verifying_key(), b"wrong")
+            dual.verify(
-            .is_err());
+                ed_signer.verifying_key(),
+                ml_signer.verifying_key(),
+                b"wrong"
+            )
+            .is_err()
+        );
     }
 
     #[cfg(feature = "hkdf")]
@@ -255,9 +255,18 @@ mod tests {
         let kr = Keyring::generate();
         let bytes = kr.to_bytes();
         let loaded = Keyring::from_bytes(&bytes).unwrap();
-        assert_eq!(kr.kem_public_key.as_bytes(), loaded.kem_public_key.as_bytes());
+        assert_eq!(
-        assert_eq!(kr.sig_pq_public_key.as_bytes(), loaded.sig_pq_public_key.as_bytes());
+            kr.kem_public_key.as_bytes(),
-        assert_eq!(kr.sig_cl_public_key.as_bytes(), loaded.sig_cl_public_key.as_bytes());
+            loaded.kem_public_key.as_bytes()
+        );
+        assert_eq!(
+            kr.sig_pq_public_key.as_bytes(),
+            loaded.sig_pq_public_key.as_bytes()
+        );
+        assert_eq!(
+            kr.sig_cl_public_key.as_bytes(),
+            loaded.sig_cl_public_key.as_bytes()
+        );
     }
 
     #[cfg(all(feature = "mlkem-tls", feature = "ml-dsa", feature = "ed25519-dalek"))]
@@ -267,7 +276,10 @@ mod tests {
         let bundle = kr.public_key_bundle();
         let bytes = bundle.as_bytes();
         let loaded = PublicKeyBundle::from_bytes(&bytes).unwrap();
-        assert_eq!(bundle.kem_public_key.as_bytes(), loaded.kem_public_key.as_bytes());
+        assert_eq!(
+            bundle.kem_public_key.as_bytes(),
+            loaded.kem_public_key.as_bytes()
+        );
         assert_eq!(
             bundle.sig_pq_public_key.as_bytes(),
             loaded.sig_pq_public_key.as_bytes()
@@ -290,8 +302,8 @@ mod tests {
     #[cfg(all(feature = "mlkem-tls", feature = "chacha20poly1305", feature = "hkdf"))]
     #[test]
     fn encrypt_multi_roundtrip() {
+        use crate::helper::{decrypt_multi, encrypt_multi};
         use crate::keypair::Keyring;
-        use crate::helper::{encrypt_multi, decrypt_multi};
 
         let kr = Keyring::generate();
         let entities = vec![kr.public_key_bundle()];

crypto/src/sign.rs

@@ -172,7 +172,9 @@ impl MlDsaSigner {
 impl SignatureScheme for MlDsaSigner {
     fn sign(&self, msg: &[u8]) -> Result<Vec<u8>, CryptoError> {
         use ml_dsa::Signer;
-        let signature = self.secret.try_sign(msg)
+        let signature = self
+            .secret
+            .try_sign(msg)
             .map_err(|_| CryptoError::SigningFailed)?;
         Ok(signature.encode().to_vec())
     }
@@ -181,7 +183,8 @@ impl SignatureScheme for MlDsaSigner {
         use ml_dsa::Verifier;
         let sig = ml_dsa::Signature::<ml_dsa::MlDsa65>::try_from(signature)
             .map_err(|_| CryptoError::InvalidSignature)?;
-        self.public.verify(msg, &sig)
+        self.public
+            .verify(msg, &sig)
             .map_err(|_| CryptoError::VerificationFailed)
     }
 }

deny.toml

@@ -0,0 +1,32 @@
+# cargo-deny configuration. See https://embarkstudios.github.io/cargo-deny/
+# Run locally with: cargo deny check
+
+[advisories]
+# Fail on any security advisory affecting the dependency tree.
+yanked = "deny"
+ignore = []
+
+[bans]
+# Flag multiple versions of the same crate so duplicate trees are visible.
+multiple-versions = "warn"
+wildcards = "deny"
+
+[licenses]
+# Allowlist of licenses acceptable for this project's dependencies.
+allow = [
+    "MIT",
+    "Apache-2.0",
+    "Apache-2.0 WITH LLVM-exception",
+    "BSD-2-Clause",
+    "BSD-3-Clause",
+    "ISC",
+    "Unicode-3.0",
+    "Zlib",
+    "MPL-2.0",
+]
+confidence-threshold = 0.8
+
+[sources]
+unknown-registry = "deny"
+unknown-git = "deny"
+allow-registry = ["https://github.com/rust-lang/crates.io-index"]

example-usage/.gitignore

@@ -3,5 +3,9 @@ host_keys.json
 host_sig_pk.bin
 host_sig_pq_pk.bin
 host_enc_kem_pk.bin
+host_public_key_bundle.hex
 clients.json
 web-client/node_modules
+dev-cert/
+web-client/public/host_public_key_bundle.hex
+web-client/public/mtp_dev_cert_hash.txt

example-usage/client/src/main.rs

@@ -2,13 +2,29 @@ mod auth;
 mod messages;
 
 use std::fs;
+use std::path::Path;
 
 use mtp::client::ClientConfig;
 use mtp::crypto::{KemPublicKey, PublicKeyBundle, SignaturePqPublicKey, SignaturePublicKey};
 
+fn dev_cert_path() -> String {
+    std::env::var("MTP_DEV_CERT").unwrap_or_else(|_| {
+        if Path::new("example-usage/dev-cert/cert.pem").exists() {
+            "example-usage/dev-cert/cert.pem".to_string()
+        } else {
+            "dev-cert/cert.pem".to_string()
+        }
+    })
+}
+
 #[tokio::main]
 async fn main() -> Result<(), Box<dyn std::error::Error>> {
-    let cert_pem = fs::read("server.pem").expect("Missing server.pem: run server first");
+    let cert_path = dev_cert_path();
+    let cert_pem = fs::read(&cert_path).unwrap_or_else(|e| {
+        panic!(
+            "Missing TLS certificate at {cert_path}: enter the Nix shell first or run the server to generate it: {e}"
+        )
+    });
     let host_public_key = PublicKeyBundle::new(
         KemPublicKey::new(
             fs::read("host_enc_kem_pk.bin")

example-usage/client/src/messages.rs

@@ -27,7 +27,10 @@ pub fn build_demo_message(
     dv_sig.sign_container(SigAlgorithm::ED25519, &signer);
 
     let inner_sec = DataValue::Container(vec![
-        (DataTypeId(1), DataValue::Str("signed+encrypted payload".into())),
+        (
+            DataTypeId(1),
+            DataValue::Str("signed+encrypted payload".into()),
+        ),
         (DataTypeId(2), DataValue::UnsignedNumber(7)),
     ]);
     let mut dv_sec = inner_sec;
@@ -38,13 +41,22 @@ pub fn build_demo_message(
         .unwrap()
         .as_secs();
 
-    CommunicationValue::new(CommunicationType::Ping)
+    let msg = CommunicationValue::new(CommunicationType::Ping)
-        .add_typed_default(DataType::Description, DataValue::Str("MTP Data Type Demo".into()))
+        .add_typed_default(
-        .add_typed_default(DataType::Timestamp, DataValue::UnsignedNumber(timestamp as u128))
+            DataType::Description,
+            DataValue::Str("MTP Data Type Demo".into()),
+        )
+        .add_typed_default(
+            DataType::Timestamp,
+            DataValue::UnsignedNumber(timestamp as u128),
+        )
         .add_typed_default(DataType::Data, DataValue::Str("Hello, MTP!".into()))
         .add_typed_default(DataType::Flags, DataValue::BoolTrue)
         .add_typed_default(DataType::Value, DataValue::Float(2, 12345))
-        .add_typed_default(DataType::BinaryData, DataValue::Bytes(vec![0xDE, 0xAD, 0xBE, 0xEF, 0x42]))
+        .add_typed_default(
+            DataType::BinaryData,
+            DataValue::Bytes(vec![0xDE, 0xAD, 0xBE, 0xEF, 0x42]),
+        )
         .add_typed_default(
             DataType::Items,
             DataValue::Array(vec![
@@ -56,7 +68,8 @@ pub fn build_demo_message(
         .add_typed_default(DataType::EncryptedPayload, dv_enc)
         .add_typed_default(DataType::SignedPayload, dv_sig)
         .add_typed_default(DataType::SecurePayload, dv_sec)
-        .with_sender(client_id)
+        .with_sender(client_id);
+    msg
 }
 
 pub async fn send_and_receive(
@@ -69,7 +82,9 @@ pub async fn send_and_receive(
     conn.sender.send(&msg).await?;
 
     match conn.receiver.receive().await {
-        Ok(resp) => println!("Received: {resp}"),
+        Ok(resp) => {
+            println!("Received: {resp}");
+        }
         Err(e) => eprintln!("Receive error: {e}"),
     }
 

example-usage/host_keys.json.stale-no-kem

@@ -0,0 +1,4 @@
+{
+  "host_id": 1,
+  "keyring": "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"
+}

example-usage/server/Cargo.toml

@@ -14,3 +14,4 @@ tokio = { version = "1", features = ["full"] }
 serde_json = { version = "1" }
 hex = "0.4"
 serde_core = "1.0.228"
+base64 = "0.22"

example-usage/server/src/clients.rs

@@ -8,14 +8,18 @@ pub fn load_client_db(
     path: &str,
 ) -> Result<(Arc<Mutex<HashMap<u64, PublicKeyBundle>>>, Arc<Mutex<u64>>), Box<dyn std::error::Error>>
 {
-    let clients: Arc<Mutex<HashMap<u64, PublicKeyBundle>>> =
+    let clients_map = match fs::read_to_string(path) {
-        Arc::new(Mutex::new(if let Ok(data) = fs::read_to_string(path) {
+        Ok(data) => match serde_json::from_str(&data) {
-            serde_json::from_str(&data).unwrap_or_default()
+            Ok(clients) => clients,
-        } else {
+            Err(e) => {
+                eprintln!("Failed to parse {path}; starting with empty client database: {e}");
                 HashMap::new()
-        }));
+            }
-    let next_id = Arc::new(Mutex::new(
+        },
-        clients.lock().unwrap().keys().max().unwrap_or(&999) + 1,
+        Err(_) => HashMap::new(),
-    ));
+    };
+    let clients: Arc<Mutex<HashMap<u64, PublicKeyBundle>>> = Arc::new(Mutex::new(clients_map));
+    let next_value = clients.lock().unwrap().keys().max().unwrap_or(&999) + 1;
+    let next_id = Arc::new(Mutex::new(next_value));
     Ok((clients, next_id))
 }

example-usage/server/src/handlers.rs

@@ -63,6 +63,7 @@ pub fn process_and_respond(
                 enc_status = format!("EncryptedPayload decrypted OK ({} entries)", entries.len());
             }
         } else {
+            eprintln!("  EncryptedPayload decryption failed");
             enc_status = String::from("EncryptedPayload: decryption FAILED");
         }
     }
@@ -75,13 +76,14 @@ pub fn process_and_respond(
             if dv.verify_into_container(&verifier).is_some() {
                 if let Some(entries) = dv.as_container() {
                     println!("  Verified SignedPayload: {:?}", entries);
-                    sig_status =
+                    sig_status = format!("SignedPayload verified OK ({} entries)", entries.len());
-                        format!("SignedPayload verified OK ({} entries)", entries.len());
                 }
             } else {
+                eprintln!("  SignedPayload verification failed");
                 sig_status = String::from("SignedPayload: verification FAILED");
             }
         } else {
+            eprintln!("  SignedPayload cannot be verified; no client public key available");
             sig_status = String::from("SignedPayload: no client public key available");
         }
     }
@@ -102,9 +104,11 @@ pub fn process_and_respond(
                     );
                 }
             } else {
+                eprintln!("  SecurePayload decryption/verification failed");
                 secure_status = String::from("SecurePayload: decryption/verification FAILED");
             }
         } else {
+            eprintln!("  SecurePayload cannot be verified; no client public key available");
             secure_status = String::from("SecurePayload: no client public key available");
         }
     }

example-usage/server/src/keys.rs

@@ -1,9 +1,11 @@
 use std::fs;
 
-use mtp::crypto::{Ed25519Signer, Keyring, MlDsaSigner};
 use mtp::crypto::kem::HybridKem;
+use mtp::crypto::{Ed25519Signer, Keyring, MlDsaSigner};
 
-pub fn load_or_generate_host_keys(path: &str) -> Result<(u64, Keyring), Box<dyn std::error::Error>> {
+pub fn load_or_generate_host_keys(
+    path: &str,
+) -> Result<(u64, Keyring), Box<dyn std::error::Error>> {
     if let Ok(data) = fs::read_to_string(path) {
         let json: serde_json::Value = serde_json::from_str(&data)?;
         let hid = json["host_id"].as_u64().unwrap_or(1);
@@ -27,6 +29,14 @@ pub fn load_or_generate_host_keys(path: &str) -> Result<(u64, Keyring), Box<dyn
 }
 
 pub fn export_host_public_keys(host_keyring: &Keyring) -> Result<(), Box<dyn std::error::Error>> {
+    let public_key_bundle_hex = hex::encode(host_keyring.public_key_bundle().as_bytes());
+
+    fs::write("host_public_key_bundle.hex", &public_key_bundle_hex)?;
+    fs::create_dir_all("web-client/public")?;
+    fs::write(
+        "web-client/public/host_public_key_bundle.hex",
+        &public_key_bundle_hex,
+    )?;
     fs::write(
         "host_enc_kem_pk.bin",
         host_keyring.kem_public_key.as_bytes(),

example-usage/server/src/main.rs

@@ -5,10 +5,34 @@ mod tls;
 
 use mtp::host::{HostConfig, MTPHost};
 use mtp::type_map::TypeMap;
+use std::path::Path;
+
+fn dev_cert_paths() -> (String, String) {
+    let cert = std::env::var("MTP_DEV_CERT").unwrap_or_else(|_| {
+        if Path::new("example-usage/dev-cert/cert.pem").exists() {
+            "example-usage/dev-cert/cert.pem".to_string()
+        } else {
+            "dev-cert/cert.pem".to_string()
+        }
+    });
+    let key = std::env::var("MTP_DEV_KEY").unwrap_or_else(|_| {
+        if Path::new("example-usage/dev-cert/key.pem").exists() {
+            "example-usage/dev-cert/key.pem".to_string()
+        } else {
+            "dev-cert/key.pem".to_string()
+        }
+    });
+    (cert, key)
+}
 
 #[tokio::main]
 async fn main() -> Result<(), Box<dyn std::error::Error>> {
-    let (cert_pem, key_pem) = tls::load_or_generate_tls("server.pem", "server.key")?;
+    let (cert_path, key_path) = dev_cert_paths();
+    let (cert_pem, key_pem) = tls::load_or_generate_tls(&cert_path, &key_path)?;
+    let cert_hash = tls::certificate_sha256_hex(&cert_pem)?;
+    tls::export_webtransport_cert_hash(&cert_hash)?;
+    println!("WebTransport certificate sha256: {cert_hash}");
+
     let (host_id, host_keyring) = keys::load_or_generate_host_keys("host_keys.json")?;
     keys::export_host_public_keys(&host_keyring)?;
 
@@ -21,7 +45,13 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
 
     let clients_for_get = clients.clone();
     let get_existing_user = Box::new(move |id: u64| -> Option<mtp::crypto::PublicKeyBundle> {
-        clients_for_get.lock().unwrap().get(&id).cloned()
+        let result = clients_for_get.lock().unwrap().get(&id).cloned();
+        if result.is_some() {
+            println!("Auth lookup: client ID {id} found");
+        } else {
+            eprintln!("Auth lookup: unknown client ID {id}");
+        }
+        result
     });
 
     let clients_for_register = clients.clone();
@@ -33,7 +63,13 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
         let id = *nid;
         *nid += 1;
         db.insert(id, bundle);
-        std::fs::write(&clients_path, serde_json::to_string_pretty(&*db).unwrap()).ok();
+        match serde_json::to_string_pretty(&*db) {
+            Ok(json) => match std::fs::write(&clients_path, json) {
+                Ok(()) => {}
+                Err(e) => eprintln!("Failed to persist client database to {clients_path}: {e}"),
+            },
+            Err(e) => eprintln!("Failed to serialize client database after registering {id}: {e}"),
+        }
         println!("Registered new client with ID: {}", id);
         id
     });

example-usage/server/src/tls.rs

@@ -1,4 +1,7 @@
 use std::fs;
+use std::path::Path;
+
+use base64::Engine;
 
 pub fn load_or_generate_tls(
     cert_path: &str,
@@ -10,6 +13,12 @@ pub fn load_or_generate_tls(
     }
 
     println!("Generating self-signed TLS certificate ...");
+    if let Some(parent) = Path::new(cert_path).parent() {
+        fs::create_dir_all(parent)?;
+    }
+    if let Some(parent) = Path::new(key_path).parent() {
+        fs::create_dir_all(parent)?;
+    }
     let key_pair = rcgen::KeyPair::generate()?;
     let params = rcgen::CertificateParams::new(vec!["localhost".into(), "127.0.0.1".into()])?;
     let cert = params.self_signed(&key_pair)?;
@@ -23,3 +32,39 @@ pub fn load_or_generate_tls(
 
     Ok((cert_str.into_bytes(), key_str.into_bytes()))
 }
+
+pub fn certificate_sha256_hex(cert: &[u8]) -> Result<String, Box<dyn std::error::Error>> {
+    let der = if cert.starts_with(b"-----BEGIN CERTIFICATE-----") {
+        let pem = std::str::from_utf8(cert)?;
+        let base64 = pem
+            .lines()
+            .filter(|line| !line.starts_with("-----"))
+            .collect::<String>();
+        base64::engine::general_purpose::STANDARD.decode(base64)?
+    } else {
+        cert.to_vec()
+    };
+
+    Ok(hex::encode(mtp::crypto::sha256(&der)))
+}
+
+pub fn export_webtransport_cert_hash(hash: &str) -> Result<(), Box<dyn std::error::Error>> {
+    let public_dir = if Path::new("web-client").exists() {
+        Path::new("web-client/public")
+    } else {
+        Path::new("example-usage/web-client/public")
+    };
+    fs::create_dir_all(public_dir)?;
+    fs::write(public_dir.join("mtp_dev_cert_hash.txt"), hash)?;
+
+    let dev_cert_dir = if Path::new("dev-cert").exists() {
+        Path::new("dev-cert")
+    } else {
+        Path::new("example-usage/dev-cert")
+    };
+    if dev_cert_dir.exists() {
+        fs::write(dev_cert_dir.join("sha256.txt"), hash)?;
+    }
+
+    Ok(())
+}

example-usage/web-client/index.html

@@ -5,8 +5,11 @@
   <meta name="viewport" content="width=device-width, initial-scale=1.0" />
   <title>MTP Web Client</title>
   <style>
-    body { font-family: monospace; background: #111; color: #0f0; padding: 2rem; }
+    body { background: #111; color: #eee; font-family: "Public Sans", sans-serif; }
-    #status { white-space: pre-wrap; }
+    label, input, textarea { display: block; margin-bottom: 0.5rem; }
+    input, textarea, button { font-family: "Public Sans", sans-serif; }
+    input, textarea { background: #222; color: #eee; }
+    #status, #key-status { white-space: pre-wrap; }
     .state { color: #ff0; }
     .received { color: #0ff; }
     .error { color: #f00; }
@@ -14,7 +17,23 @@
 </head>
 <body>
   <h1>MTP WebTransport Client</h1>
-  <div id="status">Initializing...</div>
+  <label for="server-url">Server URL</label>
+  <input id="server-url" value="https://127.0.0.1:8080" />
+
+  <label for="host-public-key">Host public key bundle hex</label>
+  <textarea id="host-public-key" placeholder="Paste PublicKeyBundle bytes as hex"></textarea>
+
+  <label for="client-public-key">Generated client public key bundle hex</label>
+  <textarea id="client-public-key" readonly></textarea>
+
+  <div>
+    <button id="generate-keypair" type="button">Generate keypair</button>
+    <button id="connect" type="button" disabled>Connect</button>
+    <button id="clear-keys" type="button">Clear saved keys</button>
+  </div>
+
+  <div id="key-status">Initializing...</div>
+  <div id="status"></div>
   <script type="module" src="/src/main.ts"></script>
 </body>
 </html>

example-usage/web-client/src/main.ts

@@ -2,15 +2,34 @@ import init, {
   WasmClient,
   ConnectionConfig,
   ConnectionState,
-  WasmEd25519Signer,
+  WasmKeyring,
   ed25519_generate,
   keyring_from_ed25519,
   build_demo_message,
+  format_frame,
 } from "mtp-wasm";
 
 const STATUS = document.getElementById("status")!;
+const KEY_STATUS = document.getElementById("key-status")!;
+const SERVER_URL = document.getElementById("server-url") as HTMLInputElement;
+const HOST_PUBLIC_KEY = document.getElementById("host-public-key") as HTMLTextAreaElement;
+const CLIENT_PUBLIC_KEY = document.getElementById("client-public-key") as HTMLTextAreaElement;
+const GENERATE_KEYPAIR = document.getElementById("generate-keypair") as HTMLButtonElement;
+const CONNECT = document.getElementById("connect") as HTMLButtonElement;
+const CLEAR_KEYS = document.getElementById("clear-keys") as HTMLButtonElement;
+
 const STORAGE_KEY = "mtp-web-client-keys";
 
+type SavedKeys = {
+  clientId: string | null;
+  keyring: number[];
+  hostPublicKey?: number[];
+};
+
+let keyringBytes: Uint8Array | null = null;
+let clientId: bigint | null = null;
+let devCertHash = "";
+
 function log(msg: string, cls = "") {
   const line = document.createElement("div");
   line.textContent = msg;
@@ -18,28 +37,103 @@ function log(msg: string, cls = "") {
   STATUS.appendChild(line);
 }
 
-function saveKeys(clientId: bigint, keyringBytes: Uint8Array) {
+function setKeyStatus(msg: string) {
-  const data = {
+  KEY_STATUS.textContent = msg;
-    clientId: clientId.toString(),
+}
+
+function bytesToHex(bytes: Uint8Array): string {
+  return Array.from(bytes, (byte) => byte.toString(16).padStart(2, "0")).join("");
+}
+
+function hexToBytes(value: string): Uint8Array {
+  const hex = value.replace(/[^0-9a-fA-F]/g, "");
+  if (hex.length === 0) throw new Error("host public key is required");
+  if (hex.length % 2 !== 0) throw new Error("host public key hex has an odd length");
+
+  const bytes = new Uint8Array(hex.length / 2);
+  for (let i = 0; i < bytes.length; i += 1) {
+    bytes[i] = Number.parseInt(hex.slice(i * 2, i * 2 + 2), 16);
+  }
+  return bytes;
+}
+
+function saveKeys() {
+  if (!keyringBytes) {
+    return;
+  }
+
+  let hostPublicKey: number[] | undefined;
+  try {
+    hostPublicKey = Array.from(hexToBytes(HOST_PUBLIC_KEY.value));
+  } catch {
+    hostPublicKey = undefined;
+  }
+
+  const data: SavedKeys = {
+    clientId: clientId?.toString() ?? null,
     keyring: Array.from(keyringBytes),
+    hostPublicKey,
   };
   localStorage.setItem(STORAGE_KEY, JSON.stringify(data));
 }
 
-function loadKeys(): { clientId: bigint; keyringBytes: Uint8Array } | null {
+function loadKeys() {
   const raw = localStorage.getItem(STORAGE_KEY);
-  if (!raw) return null;
+  if (!raw) {
-  const data = JSON.parse(raw);
+    setKeyStatus("No client keypair generated yet.");
-  return {
+    return;
-    clientId: BigInt(data.clientId),
+  }
-    keyringBytes: new Uint8Array(data.keyring),
+
-  };
+  const data = JSON.parse(raw) as SavedKeys;
+  keyringBytes = new Uint8Array(data.keyring);
+  clientId = data.clientId ? BigInt(data.clientId) : null;
+  CLIENT_PUBLIC_KEY.value = publicKeyHexFromKeyring(keyringBytes);
+  if (data.hostPublicKey) {
+    HOST_PUBLIC_KEY.value = bytesToHex(new Uint8Array(data.hostPublicKey));
+  }
+
+  setKeyStatus(
+    clientId
+      ? `Loaded saved client keypair for client ${clientId}.`
+      : "Loaded generated client keypair. Not registered yet.",
+  );
+}
+
+async function loadHostPublicKey() {
+  try {
+    const response = await fetch("/host_public_key_bundle.hex", { cache: "no-store" });
+    if (!response.ok) return;
+
+    const hostPublicKey = (await response.text()).trim();
+    if (!hostPublicKey) return;
+
+    HOST_PUBLIC_KEY.value = hostPublicKey;
+    saveKeys();
+    log(`Loaded host public key bundle (${hostPublicKey.length / 2} bytes).`);
+  } catch {
+    // Manual paste still works when the server has not exported the file yet.
+  }
+}
+
+async function loadDevCertHash() {
+  try {
+    const response = await fetch("/mtp_dev_cert_hash.txt", { cache: "no-store" });
+    if (!response.ok) return;
+
+    devCertHash = (await response.text()).trim();
+    if (devCertHash) {
+      log(`Loaded WebTransport certificate hash: ${devCertHash}`);
+    }
+  } catch {
+    devCertHash = "";
+  }
 }
 
 async function initWasm() {
   log("Loading WASM module...");
   await init();
   log(`WASM loaded. WebTransport supported: ${WasmClient.is_supported()}`);
+  CONNECT.disabled = !WasmClient.is_supported();
 }
 
 function createClient(): WasmClient {
@@ -47,11 +141,11 @@ function createClient(): WasmClient {
     (state: number) =>
       log(`[state] ${ConnectionState[state] ?? state}`, "state"),
     (data: Uint8Array) => {
-      const decoder = new TextDecoder();
+      try {
-      log(
+        log(`Received: ${format_frame(data)}`, "received");
-        `[message] ${data.length} bytes: ${decoder.decode(data)}`,
+      } catch (e) {
-        "received",
+        log(`[message parse error] ${e}`, "error");
-      );
+      }
     },
     (err: any) => log(`[error] ${err}`, "error"),
   );
@@ -65,55 +159,113 @@ function generateKeyringBytes(): Uint8Array {
   return keyring_from_ed25519(sk, pk);
 }
 
-async function run() {
+function publicKeyHexFromKeyring(bytes: Uint8Array): string {
-  await initWasm();
+  const keyring = WasmKeyring.from_bytes(bytes);
+  const publicBundle = keyring.public_key_bundle();
+  const publicHex = bytesToHex(publicBundle.to_bytes());
+  publicBundle.free();
+  keyring.free();
+  return publicHex;
+}
+
+async function connect() {
+  STATUS.textContent = "";
 
   if (!WasmClient.is_supported()) {
     log("WebTransport is not supported in this browser.", "error");
     return;
   }
-
+  if (!keyringBytes) {
-  const serverUrl = "https://127.0.0.1:8080";
+    log("Generate a client keypair first.", "error");
-  const saved = loadKeys();
+    return;
-
-  const client = createClient();
-  const config = new ConnectionConfig(serverUrl);
-
-  let clientId: bigint;
-  let keyringBytes: Uint8Array;
-
-  if (saved) {
-    log(`Found saved client keys (ID: ${saved.clientId})`);
-    const hostPk = new Uint8Array(0);
-    clientId = await client.auth_connect(
-      config,
-      hostPk,
-      saved.keyringBytes,
-      saved.clientId,
-    );
-    log(`Authenticated as client ${clientId}`);
-    keyringBytes = saved.keyringBytes;
-  } else {
-    log("No saved keys: registering new client...");
-    const hostPk = new Uint8Array(0);
-    keyringBytes = generateKeyringBytes();
-    clientId = await client.auth_register(config, hostPk, keyringBytes);
-    log(`Registered with ID: ${clientId}`);
-    saveKeys(clientId, keyringBytes);
-    log("Saved client keys to localStorage");
   }
 
-  config.free();
+  const hostPk = hexToBytes(HOST_PUBLIC_KEY.value);
+  await loadDevCertHash();
+
+  const client = createClient();
+  const serverUrl = SERVER_URL.value.trim();
+  const config = new ConnectionConfig(serverUrl);
+  if (devCertHash) {
+    log(`Pinning WebTransport certificate hash: sha-256:${devCertHash}`);
+    config.server_certificate_hashes = [`sha-256:${devCertHash}`];
+  } else {
+    log("No WebTransport certificate hash loaded; relying on browser trust store.", "state");
+  }
+
+  try {
+    let activeClientId: bigint;
+    if (clientId !== null) {
+      log(`Using saved client ID ${clientId}...`);
+      activeClientId = await client.auth_connect(
+        config,
+        hostPk,
+        keyringBytes,
+        clientId,
+      );
+      log(`Authenticated as client ${activeClientId}`);
+    } else {
+      log("Registering generated client keypair...");
+      activeClientId = await client.auth_register(config, hostPk, keyringBytes);
+      clientId = activeClientId;
+      saveKeys();
+      log(`Registered with ID: ${activeClientId}`);
+    }
 
     log("\nSending demo message...");
-  const frame = build_demo_message(clientId, keyringBytes);
+    const frame = build_demo_message(activeClientId, keyringBytes, hostPk);
+    log(`Sending: ${format_frame(frame)}`, "state");
     await client.send(frame);
     log(`Sent ${frame.length} bytes`);
 
     log("\nClient running. Waiting for incoming messages...");
+  } finally {
+    config.free();
+  }
 }
 
-run().catch((e) => {
+GENERATE_KEYPAIR.addEventListener("click", () => {
+  try {
+    keyringBytes = generateKeyringBytes();
+    clientId = null;
+    saveKeys();
+    CLIENT_PUBLIC_KEY.value = publicKeyHexFromKeyring(keyringBytes);
+    setKeyStatus("Generated client keypair. Not registered yet.");
+    log("Generated and saved a new client keypair.");
+  } catch (e) {
+    log(`Key generation failed: ${e}`, "error");
+    console.error(e);
+  }
+});
+
+CONNECT.addEventListener("click", () => {
+  connect().catch((e) => {
+    log(`Fatal error: ${e}`, "error");
+    log(
+      `[fatal context] clientId=${clientId?.toString() ?? "unregistered"}, server=${SERVER_URL.value.trim()}, hostPkChars=${HOST_PUBLIC_KEY.value.replace(/[^0-9a-fA-F]/g, "").length}, keyringBytes=${keyringBytes?.length ?? 0}, certHash=${devCertHash || "none"}`,
+      "error",
+    );
+    console.error(e);
+  });
+});
+
+CLEAR_KEYS.addEventListener("click", () => {
+  keyringBytes = null;
+  clientId = null;
+  CLIENT_PUBLIC_KEY.value = "";
+  localStorage.removeItem(STORAGE_KEY);
+  setKeyStatus("No client keypair generated yet.");
+  log("Cleared saved client keys.");
+});
+
+HOST_PUBLIC_KEY.addEventListener("change", saveKeys);
+
+initWasm()
+  .then(() => {
+    loadKeys();
+    return Promise.all([loadHostPublicKey(), loadDevCertHash()]);
+  })
+  .catch((e) => {
     log(`Fatal error: ${e}`, "error");
     console.error(e);
   });

example-usage/web-client/src/messages.ts

@@ -12,8 +12,12 @@ export function buildAuthResponse(
   return parse_auth_response(response);
 }
 
-export function buildDemoMessage(clientId: bigint, keyringBytes: Uint8Array): Uint8Array {
+export function buildDemoMessage(
-  return build_demo_message(clientId, keyringBytes);
+  clientId: bigint,
+  keyringBytes: Uint8Array,
+  hostBundle: Uint8Array,
+): Uint8Array {
+  return build_demo_message(clientId, keyringBytes, hostBundle);
 }
 
 export function buildPingFrame(

example-usage/web-client/vite.config.ts

@@ -1,6 +1,13 @@
 import { defineConfig } from 'vite';
+import fs from 'fs';
 import path from 'path';
 
+const devCertDir = path.resolve(__dirname, '../dev-cert');
+const certPath = process.env.MTP_DEV_CERT ?? path.join(devCertDir, 'cert.pem');
+const keyPath = process.env.MTP_DEV_KEY ?? path.join(devCertDir, 'key.pem');
+
+const hasDevCert = fs.existsSync(certPath) && fs.existsSync(keyPath);
+
 export default defineConfig({
   resolve: {
     alias: {
@@ -8,6 +15,12 @@ export default defineConfig({
     },
   },
   server: {
+    https: hasDevCert
+      ? {
+          cert: fs.readFileSync(certPath),
+          key: fs.readFileSync(keyPath),
+        }
+      : undefined,
     fs: {
       allow: ['.', path.resolve(__dirname, '../../wasm/pkg')],
     },

flake.nix

@@ -7,16 +7,14 @@
     flake-utils.url = "github:numtide/flake-utils";
   };
 
-  outputs =
+  outputs = {
-    {
     self,
     nixpkgs,
     rust-overlay,
     flake-utils,
   }:
     flake-utils.lib.eachDefaultSystem (
-      system:
+      system: let
-      let
         overlays = [rust-overlay.overlays.default];
         pkgs = import nixpkgs {inherit system overlays;};
 
@@ -28,9 +26,9 @@
           ];
           targets = ["wasm32-unknown-unknown"];
         };
-      in
+      in {
-      {
+        devShells = {
-        devShells.default = pkgs.mkShell {
+          default = pkgs.mkShell {
             name = "mtp-dev";
 
             buildInputs = with pkgs; [
@@ -43,14 +41,64 @@
             MTP_TYPE_MAPS = "${toString ./example-usage/type-maps.yaml}";
 
             shellHook = ''
+              repo_root="$(git rev-parse --show-toplevel 2>/dev/null || pwd)"
+              cert_dir="$repo_root/example-usage/dev-cert"
+              public_dir="$repo_root/example-usage/web-client/public"
+              cert_key="$cert_dir/key.pem"
+              cert_pem="$cert_dir/cert.pem"
+              cert_hash="$cert_dir/sha256.txt"
+
+              mkdir -p "$cert_dir"
+              mkdir -p "$public_dir"
+
+              if [ ! -f "$cert_key" ] || [ ! -f "$cert_pem" ]; then
+                openssl ecparam -name prime256v1 -genkey -noout -out "$cert_key"
+                openssl req -new -x509 \
+                  -sha256 \
+                  -key "$cert_key" \
+                  -out "$cert_pem" \
+                  -days 13 \
+                  -subj "/CN=localhost" \
+                  -addext "subjectAltName=DNS:localhost,IP:127.0.0.1" \
+                  -addext "basicConstraints=critical,CA:FALSE" \
+                  -addext "keyUsage=critical,digitalSignature" \
+                  -addext "extendedKeyUsage=serverAuth"
+                cert_status="generated"
+              else
+                cert_status="cached"
+              fi
+
+              openssl x509 -in "$cert_pem" -outform der \
+                | openssl dgst -sha256 -binary \
+                | od -An -tx1 -v \
+                | tr -d ' \n' > "$cert_hash"
+              cp "$cert_hash" "$public_dir/mtp_dev_cert_hash.txt"
+
+              export MTP_DEV_CERT="$cert_pem"
+              export MTP_DEV_KEY="$cert_key"
+              export MTP_DEV_CERT_HASH="$(cat "$cert_hash")"
+
               echo "MTP dev shell"
               echo "  rustc  : $(rustc --version)"
               echo "  cargo  : $(cargo --version)"
               echo "  wasm-pack : $(wasm-pack --version 2>/dev/null || echo 'not found')"
               echo "  targets: $(rustc --print target-list | grep wasm32 | tr '\n' ' ')"
               echo "  MTP_TYPE_MAPS = $MTP_TYPE_MAPS"
+              echo "  dev cert: $MTP_DEV_CERT ($cert_status)"
+              echo "  cert sha256: $MTP_DEV_CERT_HASH"
             '';
           };
+          autoStart = pkgs.mkShell {
+            name = "autoStart";
+            buildInputs = with pkgs; [
+              mprocs
+            ];
+            shellHook = ''
+              nix develop --command bash -c "mprocs 'cd wasm && wasm-pack build --target web --out-dir pkg && cd ../example-usage/web-client && bun dev' 'cargo b && cd example-usage && cargo r --bin server' 'cd example-usage && cargo r --bin client'"
+              exit
+            '';
+          };
+        };
 
         # Ad-hoc WASM build using wasm-pack
         apps.wasm-build = {

host/src/lib.rs

@@ -176,8 +176,9 @@ impl MTPHost {
             _ => vec![],
         };
 
-        let (assigned_id, client_bundle) =
+        let (assigned_id, client_bundle, response_type) = if msg.get_type()
-            if msg.get_type() == mtp_codec::CommunicationType::Identification.to_id(&tm) {
+            == mtp_codec::CommunicationType::Identification.to_id(&tm)
+        {
             // LOGIN
             let cid = match msg.get_data(DataType::Id.to_id(&tm)) {
                 DataValue::UnsignedNumber(n) => *n as u64,
@@ -238,7 +239,11 @@ impl MTPHost {
             }
             /* ===== End Signature ===== */
 
-            (cid, bundle)
+            (
+                cid,
+                bundle,
+                mtp_codec::CommunicationType::IdentificationResponse,
+            )
         } else if msg.get_type() == mtp_codec::CommunicationType::Register.to_id(&tm) {
             // REGISTER
             let bundle = match msg.get_data(DataType::PublicKeys.to_id(&tm)) {
@@ -285,7 +290,11 @@ impl MTPHost {
             /* ===== End Signature ===== */
 
             let new_id = (self.config.complete_register)(bundle.clone());
-            (new_id, bundle)
+            (
+                new_id,
+                bundle,
+                mtp_codec::CommunicationType::RegisterResponse,
+            )
         } else {
             sender.close();
             return None;
@@ -305,8 +314,7 @@ impl MTPHost {
         /* ===== Signature ===== */
         let host_sig = host_signer.sign(&host_sig_payload).ok()?;
 
-        let mut response =
+        let mut response = CommunicationValue::new(response_type)
-            CommunicationValue::new(mtp_codec::CommunicationType::IdentificationResponse)
             .add_typed_default(DataType::Connected, DataValue::BoolTrue)
             .add_typed_default(
                 DataType::ClientNonce,
@@ -336,6 +344,7 @@ impl MTPHost {
         /* ===== End Signature ===== */
 
         sender.send(&response).await.ok()?;
+        sender.finish_stream().await.ok()?;
 
         // 3. Version negotiation
         let negotiated = self.registry.negotiate(&[client_version])?;
@@ -380,7 +389,10 @@ mod tests {
             mtp_codec::CommunicationType::Identification,
             &tm,
         )
-        .add_data(DataType::Version.to_id(&tm), DataValue::Str("2.0".to_string()));
+        .add_data(
+            DataType::Version.to_id(&tm),
+            DataValue::Str("2.0".to_string()),
+        );
         let version = extract_version(&msg);
         assert_eq!(version, Some(Version(2, 0)));
     }

rustfmt.toml

@@ -0,0 +1 @@
+edition = "2024"

src/lib.rs

@@ -1,7 +1,7 @@
-pub use mtp_common as common;
-pub use mtp_type_map as type_map;
 pub use mtp_codec as codec;
+pub use mtp_common as common;
 pub use mtp_transport as transport;
+pub use mtp_type_map as type_map;
 
 #[cfg(feature = "crypto")]
 pub use mtp_crypto as crypto;

transport/src/connection.rs

@@ -61,7 +61,7 @@ enum ReceivedFrame {
 
 pub struct Sender {
     send_guard: Mutex<()>,
-    stream_guard: Mutex<Option<wtransport::SendStream>>,
+    stream_guard: Arc<Mutex<Option<wtransport::SendStream>>>,
     handle: Arc<ConnectionHandle>,
     connection: Connection,
     policy: Arc<Policy>,
@@ -71,7 +71,7 @@ impl Sender {
     pub fn new(connection: Connection, handle: Arc<ConnectionHandle>, policy: Arc<Policy>) -> Self {
         Self {
             send_guard: Mutex::new(()),
-            stream_guard: Mutex::new(None),
+            stream_guard: Arc::new(Mutex::new(None)),
             handle,
             connection,
             policy,
@@ -275,6 +275,18 @@ impl Sender {
         }
     }
 
+    pub async fn finish_stream(&self) -> Result<(), CommunicationError> {
+        let _send_lock = self.send_guard.lock().await;
+        let mut stream_opt = self.stream_guard.lock().await;
+        if let Some(mut stream) = stream_opt.take() {
+            timeout(self.policy.write_timeout, stream.finish())
+                .await
+                .map_err(|_| CommunicationError::StreamError)?
+                .map_err(|_| CommunicationError::StreamError)?;
+        }
+        Ok(())
+    }
+
     pub fn handle(&self) -> &Arc<ConnectionHandle> {
         &self.handle
     }
@@ -283,6 +295,7 @@ impl Sender {
         let connection = self.connection.clone();
         let handle = self.handle.clone();
         let policy = self.policy.clone();
+        let stream_guard = self.stream_guard.clone();
 
         tokio::spawn(async move {
             if connection.quic_connection().close_reason().is_some() || handle.is_closed() {
@@ -290,6 +303,14 @@ impl Sender {
                 return;
             }
 
+            if let Some(mut stream) = stream_guard.lock().await.take() {
+                match timeout(policy.write_timeout, stream.finish()).await {
+                    Ok(Ok(())) => {}
+                    Ok(Err(e)) => log::warn!("[Sender] persistent stream finish failed: {e}"),
+                    Err(_) => log::warn!("[Sender] persistent stream finish timed out"),
+                }
+            }
+
             let _ = Self::send_close_frame(&connection, &policy).await;
 
             handle.close(Some(CommunicationError::StreamClosed));
@@ -323,6 +344,18 @@ pub struct Receiver {
     handle: Arc<ConnectionHandle>,
 }
 
+impl Drop for Receiver {
+    fn drop(&mut self) {
+        // The accept loop holds clones of the connection and the shared
+        // ConnectionHandle. Without this, dropping a Receiver without first
+        // closing the connection would leave that task running forever. Abort
+        // it directly rather than closing the shared handle, so a still-live
+        // Sender on the same connection is unaffected. abort() is a no-op if
+        // the task already finished (e.g. the connection was closed).
+        self._accept_task.abort();
+    }
+}
+
 impl Receiver {
     pub fn new(connection: Connection, handle: Arc<ConnectionHandle>, policy: Arc<Policy>) -> Self {
         let (tx, rx) = mpsc::channel::<Result<CommunicationValue, CommunicationError>>(

transport/src/connection_handle.rs

@@ -53,7 +53,7 @@ impl ConnectionHandle {
         if self.is_closed() {
             return rx.borrow().clone();
         }
-        let _ = rx.changed().await.ok()?;
+        rx.changed().await.ok()?;
         rx.borrow().clone()
     }
 }

transport/src/host.rs

@@ -26,6 +26,22 @@ impl Host {
     pub fn local_addr(&self) -> std::net::SocketAddr {
         self.local_addr
     }
+
+    /// Stop accepting new connections. Already-accepted connections run on their
+    /// own spawned tasks and are not affected.
+    pub fn shutdown(&mut self) {
+        self._task.abort();
+    }
+}
+
+impl Drop for Host {
+    fn drop(&mut self) {
+        // The accept loop runs forever on its own task; dropping the Host
+        // JoinHandle would only detach it. Abort it so dropping the Host
+        // actually stops accepting new connections. Per-connection handler
+        // tasks are spawned independently and keep running.
+        self._task.abort();
+    }
 }
 
 pub async fn host(

transport/tests/integration.rs

@@ -1,6 +1,6 @@
 use std::net::{IpAddr, Ipv4Addr};
 
-use mtp_transport::{Policy, host, connect};
+use mtp_transport::{Policy, connect, host};
 
 fn generate_self_signed_cert() -> (Vec<u8>, Vec<u8>) {
     let key_pair = rcgen::KeyPair::generate().unwrap();
@@ -44,15 +44,15 @@ async fn test_send_receive_roundtrip() {
     let addr = h.local_addr();
 
     let url = format!("https://127.0.0.1:{}", addr.port());
-    let (client_tx, client_rx) =
+    let (client_tx, client_rx) = connect(&url, Some(cert_pem), Policy::default())
-        connect(&url, Some(cert_pem), Policy::default()).await.unwrap();
+        .await
+        .unwrap();
 
     // Accept on host side
     let (host_tx, host_rx) = h.next().await.unwrap();
 
     // Client sends a simple message
-    let msg = mtp_codec::CommunicationValue::new(mtp_codec::CommunicationType::Ping)
+    let msg = mtp_codec::CommunicationValue::new(mtp_codec::CommunicationType::Ping).add_data(
-        .add_data(
         mtp_codec::DataTypeId(6),
         mtp_codec::DataValue::UnsignedNumber(42),
     );
@@ -65,8 +65,7 @@ async fn test_send_receive_roundtrip() {
     assert_eq!(val, mtp_codec::DataValue::UnsignedNumber(42));
 
     // Host sends a response
-    let resp = mtp_codec::CommunicationValue::new(mtp_codec::CommunicationType::Pong)
+    let resp = mtp_codec::CommunicationValue::new(mtp_codec::CommunicationType::Pong).add_data(
-        .add_data(
         mtp_codec::DataTypeId(6),
         mtp_codec::DataValue::UnsignedNumber(99),
     );
@@ -74,7 +73,10 @@ async fn test_send_receive_roundtrip() {
 
     // Client receives it
     let client_received = client_rx.receive().await.unwrap();
-    assert_eq!(client_received.get_type(), mtp_codec::CommunicationTypeId(20)); // Pong
+    assert_eq!(
+        client_received.get_type(),
+        mtp_codec::CommunicationTypeId(20)
+    ); // Pong
     let client_val = client_received.get_data(mtp_codec::DataTypeId(6)).clone();
     assert_eq!(client_val, mtp_codec::DataValue::UnsignedNumber(99));
 
@@ -98,15 +100,15 @@ async fn test_concurrent_messages() {
     let addr = h.local_addr();
 
     let url = format!("https://127.0.0.1:{}", addr.port());
-    let (client_tx, _client_rx) =
+    let (client_tx, _client_rx) = connect(&url, Some(cert_pem), Policy::default())
-        connect(&url, Some(cert_pem), Policy::default()).await.unwrap();
+        .await
+        .unwrap();
 
     let (_host_tx, host_rx) = h.next().await.unwrap();
 
     // Send 5 messages in sequence
     for i in 0..5u128 {
-        let msg = mtp_codec::CommunicationValue::new(mtp_codec::CommunicationType::Ping)
+        let msg = mtp_codec::CommunicationValue::new(mtp_codec::CommunicationType::Ping).add_data(
-            .add_data(
             mtp_codec::DataTypeId(6),
             mtp_codec::DataValue::UnsignedNumber(i),
         );
@@ -122,8 +124,7 @@ async fn test_concurrent_messages() {
 
     // Send 3 responses back
     for i in 0..3u128 {
-        let msg = mtp_codec::CommunicationValue::new(mtp_codec::CommunicationType::Pong)
+        let msg = mtp_codec::CommunicationValue::new(mtp_codec::CommunicationType::Pong).add_data(
-            .add_data(
             mtp_codec::DataTypeId(6),
             mtp_codec::DataValue::UnsignedNumber(i * 10),
         );
@@ -154,8 +155,9 @@ async fn test_close_detection() {
     let addr = h.local_addr();
 
     let url = format!("https://127.0.0.1:{}", addr.port());
-    let (client_tx, _client_rx) =
+    let (client_tx, _client_rx) = connect(&url, Some(cert_pem), Policy::default())
-        connect(&url, Some(cert_pem), Policy::default()).await.unwrap();
+        .await
+        .unwrap();
 
     let (_host_tx, host_rx) = h.next().await.unwrap();
 
@@ -172,3 +174,87 @@ async fn test_close_detection() {
     let result = host_rx.receive().await;
     assert!(result.is_err());
 }
+
+#[tokio::test]
+async fn test_host_shutdown_stops_accepting() {
+    let (cert_pem, key_pem) = generate_self_signed_cert();
+    let mut h = host(
+        IpAddr::V4(Ipv4Addr::LOCALHOST),
+        0,
+        cert_pem.clone(),
+        key_pem,
+        Policy::default(),
+    )
+    .await
+    .unwrap();
+    let addr = h.local_addr();
+    let url = format!("https://127.0.0.1:{}", addr.port());
+
+    // A connection succeeds while the host is accepting.
+    let (_c_tx, _c_rx) = connect(&url, Some(cert_pem.clone()), Policy::default())
+        .await
+        .unwrap();
+    let _accepted = h.next().await.unwrap();
+
+    // After shutdown the accept task is aborted and its endpoint is dropped, so
+    // new connections no longer succeed. Guard with a timeout so a hung connect
+    // still fails the assertion rather than blocking the test.
+    h.shutdown();
+
+    let result = tokio::time::timeout(
+        std::time::Duration::from_secs(5),
+        connect(&url, Some(cert_pem), Policy::default()),
+    )
+    .await;
+    assert!(
+        matches!(result, Err(_) | Ok(Err(_))),
+        "connect should not succeed after host shutdown"
+    );
+}
+
+#[tokio::test]
+async fn test_drop_receiver_keeps_sender_alive() {
+    let (cert_pem, key_pem) = generate_self_signed_cert();
+    let mut h = host(
+        IpAddr::V4(Ipv4Addr::LOCALHOST),
+        0,
+        cert_pem.clone(),
+        key_pem,
+        Policy::default(),
+    )
+    .await
+    .unwrap();
+    let addr = h.local_addr();
+
+    let url = format!("https://127.0.0.1:{}", addr.port());
+    let (client_tx, client_rx) = connect(&url, Some(cert_pem), Policy::default())
+        .await
+        .unwrap();
+
+    let (host_tx, host_rx) = h.next().await.unwrap();
+
+    // Client sends a message the host receives.
+    let msg = mtp_codec::CommunicationValue::new(mtp_codec::CommunicationType::Ping);
+    client_tx.send(&msg).await.unwrap();
+    let _ = host_rx.receive().await.unwrap();
+
+    // Dropping the host Receiver aborts only its accept task; the Sender shares
+    // the same connection and must keep working.
+    drop(host_rx);
+
+    let resp = mtp_codec::CommunicationValue::new(mtp_codec::CommunicationType::Pong).add_data(
+        mtp_codec::DataTypeId(6),
+        mtp_codec::DataValue::UnsignedNumber(7),
+    );
+    host_tx.send(&resp).await.unwrap();
+
+    let got = client_rx.receive().await.unwrap();
+    assert_eq!(got.get_type(), mtp_codec::CommunicationTypeId(20)); // Pong
+    assert_eq!(
+        got.get_data(mtp_codec::DataTypeId(6)).clone(),
+        mtp_codec::DataValue::UnsignedNumber(7)
+    );
+
+    client_tx.close();
+    host_tx.close();
+}

type-map/build.rs

@@ -220,7 +220,7 @@ fn generate(config: &Config, multi_version: bool) -> String {
     let (all_comm_names, all_data_names, sorted) = if multi_version {
         let mut all_comm_names: BTreeSet<&str> = BTreeSet::new();
         let mut all_data_names: BTreeSet<&str> = BTreeSet::new();
-        for (_version_key, tm) in &config.type_maps {
+        for tm in config.type_maps.values() {
             for name in tm.communication_types.keys() {
                 all_comm_names.insert(name.as_str());
             }

type-map/src/lib.rs

@@ -1,3 +1,8 @@
+// try_new returns Result<Self, ()> deliberately: the only failure mode is "id
+// is in the reserved range", which carries no extra information worth an error
+// type. The unit error is the intended API.
+#![allow(clippy::result_unit_err)]
+
 pub const INTERNAL_COMM_RESERVED: std::ops::Range<u16> = 0..32;
 pub const INTERNAL_DATA_RESERVED: std::ops::Range<u16> = 0..32;
 

wasm/.cargo/config.toml

@@ -1,5 +1,6 @@
+# Default to the wasm32 target when running cargo from inside this crate dir.
+# The web_sys_unstable_apis cfg lives in the workspace-root .cargo/config.toml,
+# scoped to [target.wasm32-unknown-unknown], so it applies here too (the root
+# config is an ancestor) and to `-p mtp-wasm` builds invoked from the root.
 [build]
 target = "wasm32-unknown-unknown"
-
-[target.wasm32-unknown-unknown]
-rustflags = ["--cfg=web_sys_unstable_apis"]

wasm/src/client.rs

@@ -3,16 +3,80 @@ use std::rc::Rc;
 
 use wasm_bindgen::prelude::*;
 
-use mtp_codec::{
+use mtp_codec::{CommunicationType, CommunicationValue, DataType, DataValue, PROTOCOL_VERSION};
-    CommunicationType, CommunicationValue, DataType, DataValue, PROTOCOL_VERSION,
+use mtp_type_map::CommunicationTypeId;
-};
-use mtp_type_map::{CommunicationTypeId, DataTypeId};
 
 use mtp_crypto::SignatureScheme;
 
 use crate::error::js_error;
 use crate::transport::WasmTransport;
 
+fn raw_frame_preview(bytes: &[u8]) -> String {
+    let shown = bytes.len().min(256);
+    let mut preview = hex::encode(&bytes[..shown]);
+    if bytes.len() > shown {
+        preview.push_str("...");
+    }
+    format!("{} bytes, hex={preview}", bytes.len())
+}
+
+fn unexpected_response_type_error(
+    context: &str,
+    expected_type: CommunicationTypeId,
+    response_type: CommunicationTypeId,
+    response: &[u8],
+    parsed: &CommunicationValue,
+) -> JsValue {
+    js_error(&format!(
+        "unexpected response type during {context}: expected {:?}, got {:?}; raw {}; parsed {}",
+        expected_type,
+        response_type,
+        raw_frame_preview(response),
+        parsed
+    ))
+}
+
+/// Verify the host's authentication signature over the handshake response,
+/// mirroring the native client (`client/src/lib.rs`). The signed payload is
+/// `0x01 || id.to_be_bytes() || client_nonce.to_be_bytes() || host_nonce.to_be_bytes()`,
+/// where `id` is the client id for login and the host-assigned id for register.
+/// The Ed25519 signature is mandatory; the ML-DSA signature is verified only
+/// when the host included one.
+fn verify_host_signature(
+    resp: &CommunicationValue,
+    tm: &mtp_codec::TypeMap,
+    host_pk: &mtp_crypto::PublicKeyBundle,
+    id: u64,
+    client_nonce: u128,
+) -> Result<(), JsValue> {
+    let host_new_nonce = match resp.get_data(DataType::Timestamp.to_id(tm)) {
+        DataValue::UnsignedNumber(n) => *n,
+        _ => return Err(js_error("missing host nonce")),
+    };
+    let host_sig = match resp.get_data(DataType::Signature.to_id(tm)) {
+        DataValue::Bytes(b) => b.clone(),
+        _ => return Err(js_error("missing host signature")),
+    };
+    let host_pq_sig = match resp.get_data(DataType::PqSignature.to_id(tm)) {
+        DataValue::Bytes(b) => b.clone(),
+        _ => vec![],
+    };
+
+    let mut payload = Vec::new();
+    payload.push(0x01);
+    payload.extend_from_slice(&id.to_be_bytes());
+    payload.extend_from_slice(&client_nonce.to_be_bytes());
+    payload.extend_from_slice(&host_new_nonce.to_be_bytes());
+
+    mtp_crypto::verify_ed25519(&host_pk.sig_cl_public_key, &payload, &host_sig)
+        .map_err(|_| js_error("host signature invalid"))?;
+    if !host_pq_sig.is_empty() {
+        mtp_crypto::verify_ml_dsa(&host_pk.sig_pq_public_key, &payload, &host_pq_sig)
+            .map_err(|_| js_error("host PQ signature invalid"))?;
+    }
+    Ok(())
+}
+
 #[wasm_bindgen]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub enum ConnectionState {
@@ -33,17 +97,27 @@ pub struct ConnectionConfig {
 impl ConnectionConfig {
     #[wasm_bindgen(constructor)]
     pub fn new(url: String) -> Self {
-        Self { url, server_certificate_hashes: None, client_id: 0 }
+        Self {
+            url,
+            server_certificate_hashes: None,
+            client_id: 0,
+        }
     }
 
     #[wasm_bindgen(getter)]
-    pub fn url(&self) -> String { self.url.clone() }
+    pub fn url(&self) -> String {
+        self.url.clone()
+    }
 
     #[wasm_bindgen(setter)]
-    pub fn set_client_id(&mut self, id: u64) { self.client_id = id; }
+    pub fn set_client_id(&mut self, id: u64) {
+        self.client_id = id;
+    }
 
     #[wasm_bindgen(getter)]
-    pub fn client_id(&self) -> u64 { self.client_id }
+    pub fn client_id(&self) -> u64 {
+        self.client_id
+    }
 
     #[wasm_bindgen(setter)]
     pub fn set_server_certificate_hashes(&mut self, hashes: Vec<String>) {
@@ -79,24 +153,29 @@ impl WasmClient {
 
     #[wasm_bindgen]
     pub fn is_supported() -> bool {
-        js_sys::Reflect::has(&js_sys::global(), &JsValue::from_str("WebTransport"))
+        js_sys::Reflect::has(&js_sys::global(), &JsValue::from_str("WebTransport")).unwrap_or(false)
-            .unwrap_or(false)
     }
 
     #[wasm_bindgen(getter)]
-    pub fn state(&self) -> u8 { self.state.get() as u8 }
+    pub fn state(&self) -> u8 {
+        self.state.get() as u8
+    }
 
     /// Unauthenticated connect (sends basic Identification, enables receive loop).
     #[wasm_bindgen]
     pub async fn connect(&mut self, config: &ConnectionConfig) -> Result<(), JsValue> {
         self.set_state(ConnectionState::Connecting);
-        let transport = WasmTransport::connect(&config.url, config.server_certificate_hashes.clone()).await?;
+        let transport =
+            WasmTransport::connect(&config.url, config.server_certificate_hashes.clone()).await?;
         let inner = transport.inner().clone();
 
         let version_str = format!("{}", PROTOCOL_VERSION);
         let ident = CommunicationValue::new(CommunicationType::Identification)
             .add_typed_default(DataType::Version, DataValue::Str(version_str))
-            .add_typed_default(DataType::Id, DataValue::UnsignedNumber(config.client_id as u128));
+            .add_typed_default(
+                DataType::Id,
+                DataValue::UnsignedNumber(config.client_id as u128),
+            );
         let ident_bytes = ident
             .to_bytes()
             .map_err(|e| js_error(&format!("encode failed: {}", e)))?;
@@ -109,7 +188,9 @@ impl WasmClient {
         let on_msg = self.on_message.clone();
         let on_err = self.on_error.clone();
         wasm_bindgen_futures::spawn_local(async move {
-            WasmTransport::from_inner(inner).receive_loop(on_msg, on_err).await;
+            WasmTransport::from_inner(inner)
+                .receive_loop(on_msg, on_err)
+                .await;
             state.set(ConnectionState::Disconnected);
         });
         Ok(())
@@ -127,19 +208,20 @@ impl WasmClient {
     pub async fn auth_connect(
         &mut self,
         config: &ConnectionConfig,
-        _host_public_key_bytes: &[u8],
+        host_public_key_bytes: &[u8],
         keyring_bytes: &[u8],
         client_id: u64,
     ) -> Result<u64, JsValue> {
         self.set_state(ConnectionState::Connecting);
 
+        let host_pk = mtp_crypto::PublicKeyBundle::from_bytes(host_public_key_bytes)
+            .map_err(|e| js_error(&format!("invalid host public key: {}", e)))?;
         let keyring = mtp_crypto::Keyring::from_bytes(keyring_bytes)
             .map_err(|e| js_error(&format!("invalid keyring: {}", e)))?;
 
         let version_str = format!("{}", PROTOCOL_VERSION);
         let mut nonce_bytes = [0u8; 16];
-        getrandom::fill(&mut nonce_bytes)
+        getrandom::fill(&mut nonce_bytes).map_err(|_| js_error("rng failed"))?;
-            .map_err(|_| js_error("rng failed"))?;
         let client_nonce = u128::from_be_bytes(nonce_bytes);
 
         // Build signature payload: version || client_id || client_nonce
@@ -150,18 +232,23 @@ impl WasmClient {
 
         let signer = mtp_crypto::Ed25519Signer::new(&keyring.sig_cl_secret_key)
             .map_err(|e| js_error(&format!("signer creation failed: {}", e)))?;
-        let signature = signer.sign(&sig_payload)
+        let signature = signer
+            .sign(&sig_payload)
             .map_err(|e| js_error(&format!("signature failed: {}", e)))?;
 
         let frame = CommunicationValue::new(CommunicationType::Identification)
             .add_typed_default(DataType::Version, DataValue::Str(version_str))
             .add_typed_default(DataType::Id, DataValue::UnsignedNumber(client_id as u128))
-            .add_typed_default(DataType::ClientNonce, DataValue::UnsignedNumber(client_nonce))
+            .add_typed_default(
+                DataType::ClientNonce,
+                DataValue::UnsignedNumber(client_nonce),
+            )
             .add_typed_default(DataType::Signature, DataValue::Bytes(signature))
             .to_bytes()
             .map_err(|e| js_error(&format!("encode failed: {}", e)))?;
 
-        let transport = WasmTransport::connect(&config.url, config.server_certificate_hashes.clone()).await?;
+        let transport =
+            WasmTransport::connect(&config.url, config.server_certificate_hashes.clone()).await?;
         let inner = transport.inner().clone();
         transport.send_frame(&frame).await?;
 
@@ -170,26 +257,45 @@ impl WasmClient {
         let resp_comm = CommunicationValue::from_bytes(&response)
             .map_err(|e| js_error(&format!("parse response: {}", e)))?;
 
+        let tm = mtp_codec::TypeMap::latest();
         let resp_type = resp_comm.get_type();
-        let expected_type = CommunicationTypeId(16); // IdentificationResponse
+        let expected_type = CommunicationType::IdentificationResponse.to_id(&tm);
         if resp_type != expected_type {
-            return Err(js_error("unexpected response type"));
+            self.set_state(ConnectionState::Disconnected);
+            return Err(unexpected_response_type_error(
+                "auth_connect",
+                expected_type,
+                resp_type,
+                &response,
+                &resp_comm,
+            ));
         }
 
-        if resp_comm.get_data(DataTypeId(11)) != &DataValue::BoolTrue {
+        if resp_comm.get_data(DataType::Connected.to_id(&tm)) != &DataValue::BoolTrue {
+            self.set_state(ConnectionState::Disconnected);
             return Err(js_error("host rejected authentication"));
         }
 
         // Verify echoed nonce
-        let echo_nonce = resp_comm.get_data(DataTypeId(7));
+        let echo_nonce = resp_comm.get_data(DataType::ClientNonce.to_id(&tm));
         if *echo_nonce != DataValue::UnsignedNumber(client_nonce) {
+            self.set_state(ConnectionState::Disconnected);
             return Err(js_error("nonce mismatch"));
         }
 
+        // Verify the host's signature over the handshake (login: id is client_id).
+        if let Err(e) = verify_host_signature(&resp_comm, &tm, &host_pk, client_id, client_nonce) {
+            self.set_state(ConnectionState::Disconnected);
+            return Err(e);
+        }
+
         // Extract assigned ID
-        let assigned_id = match resp_comm.get_data(DataTypeId(6)) {
+        let assigned_id = match resp_comm.get_data(DataType::Id.to_id(&tm)) {
             DataValue::UnsignedNumber(n) => *n as u64,
-            _ => return Err(js_error("missing assigned ID")),
+            _ => {
+                self.set_state(ConnectionState::Disconnected);
+                return Err(js_error("missing assigned ID"));
+            }
         };
 
         self.transport = Some(transport);
@@ -199,7 +305,9 @@ impl WasmClient {
         let on_msg = self.on_message.clone();
         let on_err = self.on_error.clone();
         wasm_bindgen_futures::spawn_local(async move {
-            WasmTransport::from_inner(inner).receive_loop(on_msg, on_err).await;
+            WasmTransport::from_inner(inner)
+                .receive_loop(on_msg, on_err)
+                .await;
             state.set(ConnectionState::Disconnected);
         });
 
@@ -222,15 +330,14 @@ impl WasmClient {
     ) -> Result<u64, JsValue> {
         self.set_state(ConnectionState::Connecting);
 
-        let _host_pk = mtp_crypto::PublicKeyBundle::from_bytes(host_public_key_bytes)
+        let host_pk = mtp_crypto::PublicKeyBundle::from_bytes(host_public_key_bytes)
             .map_err(|e| js_error(&format!("invalid host public key: {}", e)))?;
         let keyring = mtp_crypto::Keyring::from_bytes(keyring_bytes)
             .map_err(|e| js_error(&format!("invalid keyring: {}", e)))?;
 
         let version_str = format!("{}", PROTOCOL_VERSION);
         let mut nonce_bytes = [0u8; 16];
-        getrandom::fill(&mut nonce_bytes)
+        getrandom::fill(&mut nonce_bytes).map_err(|_| js_error("rng failed"))?;
-            .map_err(|_| js_error("rng failed"))?;
         let client_nonce = u128::from_be_bytes(nonce_bytes);
 
         let pk_bytes = keyring.public_key_bundle().as_bytes();
@@ -243,18 +350,23 @@ impl WasmClient {
 
         let signer = mtp_crypto::Ed25519Signer::new(&keyring.sig_cl_secret_key)
             .map_err(|e| js_error(&format!("signer creation failed: {}", e)))?;
-        let signature = signer.sign(&sig_payload)
+        let signature = signer
+            .sign(&sig_payload)
             .map_err(|e| js_error(&format!("signature failed: {}", e)))?;
 
         let frame = CommunicationValue::new(CommunicationType::Register)
             .add_typed_default(DataType::Version, DataValue::Str(version_str))
-            .add_typed_default(DataType::ClientNonce, DataValue::UnsignedNumber(client_nonce))
+            .add_typed_default(
+                DataType::ClientNonce,
+                DataValue::UnsignedNumber(client_nonce),
+            )
             .add_typed_default(DataType::PublicKeys, DataValue::Bytes(pk_bytes))
             .add_typed_default(DataType::Signature, DataValue::Bytes(signature))
             .to_bytes()
             .map_err(|e| js_error(&format!("encode failed: {}", e)))?;
 
-        let transport = WasmTransport::connect(&config.url, config.server_certificate_hashes.clone()).await?;
+        let transport =
+            WasmTransport::connect(&config.url, config.server_certificate_hashes.clone()).await?;
         let inner = transport.inner().clone();
         transport.send_frame(&frame).await?;
 
@@ -262,26 +374,47 @@ impl WasmClient {
         let resp_comm = CommunicationValue::from_bytes(&response)
             .map_err(|e| js_error(&format!("parse response: {}", e)))?;
 
+        let tm = mtp_codec::TypeMap::latest();
         let resp_type = resp_comm.get_type();
-        let expected_type = CommunicationTypeId(18); // RegisterResponse
+        let expected_type = CommunicationType::RegisterResponse.to_id(&tm);
         if resp_type != expected_type {
-            return Err(js_error("unexpected response type"));
+            self.set_state(ConnectionState::Disconnected);
+            return Err(unexpected_response_type_error(
+                "auth_register",
+                expected_type,
+                resp_type,
+                &response,
+                &resp_comm,
+            ));
         }
 
-        if resp_comm.get_data(DataTypeId(11)) != &DataValue::BoolTrue {
+        if resp_comm.get_data(DataType::Connected.to_id(&tm)) != &DataValue::BoolTrue {
+            self.set_state(ConnectionState::Disconnected);
             return Err(js_error("host rejected registration"));
         }
 
-        let echo = resp_comm.get_data(DataTypeId(7));
+        let echo = resp_comm.get_data(DataType::ClientNonce.to_id(&tm));
         if *echo != DataValue::UnsignedNumber(client_nonce) {
+            self.set_state(ConnectionState::Disconnected);
             return Err(js_error("nonce mismatch"));
         }
 
-        let assigned_id = match resp_comm.get_data(DataTypeId(6)) {
+        let assigned_id = match resp_comm.get_data(DataType::Id.to_id(&tm)) {
             DataValue::UnsignedNumber(n) => *n as u64,
-            _ => return Err(js_error("missing assigned ID")),
+            _ => {
+                self.set_state(ConnectionState::Disconnected);
+                return Err(js_error("missing assigned ID"));
+            }
         };
 
+        // Verify the host's signature over the handshake (register: id is the
+        // host-assigned id).
+        if let Err(e) = verify_host_signature(&resp_comm, &tm, &host_pk, assigned_id, client_nonce)
+        {
+            self.set_state(ConnectionState::Disconnected);
+            return Err(e);
+        }
+
         self.transport = Some(transport);
         self.set_state(ConnectionState::Connected);
 
@@ -289,7 +422,9 @@ impl WasmClient {
         let on_msg = self.on_message.clone();
         let on_err = self.on_error.clone();
         wasm_bindgen_futures::spawn_local(async move {
-            WasmTransport::from_inner(inner).receive_loop(on_msg, on_err).await;
+            WasmTransport::from_inner(inner)
+                .receive_loop(on_msg, on_err)
+                .await;
             state.set(ConnectionState::Disconnected);
         });
 
@@ -306,16 +441,17 @@ impl WasmClient {
 
     #[wasm_bindgen]
     pub fn disconnect(&mut self) {
-        if let Some(t) = &self.transport { t.close(); }
+        if let Some(t) = &self.transport {
+            t.close();
+        }
         self.transport = None;
         self.set_state(ConnectionState::Disconnected);
     }
 
     fn set_state(&self, new_state: ConnectionState) {
         self.state.set(new_state);
-        let _ = self.on_state_change.call1(
+        let _ = self
-            &JsValue::NULL,
+            .on_state_change
-            &JsValue::from(new_state as u8),
+            .call1(&JsValue::NULL, &JsValue::from(new_state as u8));
-        );
     }
 }

wasm/src/crypto.rs

@@ -1,9 +1,9 @@
 use wasm_bindgen::prelude::*;
 
 use mtp_crypto::{
-    AeadDecrypt, AeadEncrypt, Ed25519Signer, KemPrivateKey, KemPublicKey, Keyring,
+    AeadDecrypt, AeadEncrypt, ChaCha20Poly1305, Ed25519Signer, KemPrivateKey, KemPublicKey,
-    PublicKeyBundle, SignaturePqPrivateKey, SignaturePqPublicKey, SignaturePrivateKey,
+    Keyring, PublicKeyBundle, SignaturePqPrivateKey, SignaturePqPublicKey, SignaturePrivateKey,
-    SignaturePublicKey, SignatureScheme, ChaCha20Poly1305, sha256, sha256_double,
+    SignaturePublicKey, SignatureScheme, sha256, sha256_double,
 };
 
 use crate::error::js_error;
@@ -28,8 +28,8 @@ impl WasmKeyring {
     /// Deserialise a keyring from bytes.
     #[wasm_bindgen]
     pub fn from_bytes(bytes: &[u8]) -> Result<WasmKeyring, JsValue> {
-        let inner =
+        let inner = Keyring::from_bytes(bytes)
-            Keyring::from_bytes(bytes).map_err(|e| js_error(&format!("Keyring::from_bytes: {}", e)))?;
+            .map_err(|e| js_error(&format!("Keyring::from_bytes: {}", e)))?;
         Ok(Self { inner })
     }
 
@@ -217,7 +217,11 @@ pub fn ed25519_generate() -> Result<JsValue, JsValue> {
 
 /// Standalone Ed25519 signature verification.
 #[wasm_bindgen]
-pub fn ed25519_verify(public_key: Vec<u8>, message: &[u8], signature: &[u8]) -> Result<(), JsValue> {
+pub fn ed25519_verify(
+    public_key: Vec<u8>,
+    message: &[u8],
+    signature: &[u8],
+) -> Result<(), JsValue> {
     let pk = SignaturePublicKey::new(public_key);
     mtp_crypto::verify_ed25519(&pk, message, signature)
         .map_err(|e| js_error(&format!("verify_ed25519 failed: {}", e)))
@@ -245,7 +249,12 @@ pub fn wasm_sha256_double(data: &[u8]) -> Vec<u8> {
 
 /// HKDF-expand: derive `len` bytes from `ikm` with `salt` and `info`.
 #[wasm_bindgen]
-pub fn wasm_hkdf_expand(ikm: &[u8], salt: &[u8], info: &[u8], len: usize) -> Result<Vec<u8>, JsValue> {
+pub fn wasm_hkdf_expand(
+    ikm: &[u8],
+    salt: &[u8],
+    info: &[u8],
+    len: usize,
+) -> Result<Vec<u8>, JsValue> {
     mtp_crypto::hkdf_expand(ikm, salt, info, len)
         .map_err(|e| js_error(&format!("hkdf_expand failed: {}", e)))
 }
@@ -416,7 +425,8 @@ mod tests {
     fn sha256_empty() {
         let result = wasm_sha256(b"");
         // SHA-256 of empty string
-        let expected = hex::decode("e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855")
+        let expected =
+            hex::decode("e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855")
                 .expect("hex decode");
         assert_eq!(result, expected);
     }
@@ -424,7 +434,8 @@ mod tests {
     #[wasm_bindgen_test]
     fn sha256_hello() {
         let result = wasm_sha256(b"hello");
-        let expected = hex::decode("2cf24dba5fb0a30e26e83b2ac5b9e29e1b161e5c1fa7425e73043362938b9824")
+        let expected =
+            hex::decode("2cf24dba5fb0a30e26e83b2ac5b9e29e1b161e5c1fa7425e73043362938b9824")
                 .expect("hex decode");
         assert_eq!(result, expected);
     }
@@ -443,8 +454,7 @@ mod tests {
 
     #[wasm_bindgen_test]
     fn hkdf_expand_produces_correct_length() {
-        let result = wasm_hkdf_expand(b"ikm", b"salt", b"info", 32)
+        let result = wasm_hkdf_expand(b"ikm", b"salt", b"info", 32).expect("hkdf_expand failed");
-            .expect("hkdf_expand failed");
         assert_eq!(result.len(), 32);
     }
 
@@ -457,22 +467,21 @@ mod tests {
 
     #[wasm_bindgen_test]
     fn derive_encryption_key_roundtrip() {
-        let key = wasm_derive_encryption_key(b"password", b"salt", b"context")
+        let key =
-            .expect("derive failed");
+            wasm_derive_encryption_key(b"password", b"salt", b"context").expect("derive failed");
         assert_eq!(key.len(), 32);
 
         // Deterministic: same inputs = same key
-        let key2 = wasm_derive_encryption_key(b"password", b"salt", b"context")
+        let key2 =
-            .expect("derive failed");
+            wasm_derive_encryption_key(b"password", b"salt", b"context").expect("derive failed");
         assert_eq!(key, key2);
     }
 
     #[wasm_bindgen_test]
     fn derive_encryption_key_different_inputs_different_key() {
-        let key = wasm_derive_encryption_key(b"pass1", b"salt", b"context")
+        let key = wasm_derive_encryption_key(b"pass1", b"salt", b"context").expect("derive failed");
-            .expect("derive failed");
+        let key2 =
-        let key2 = wasm_derive_encryption_key(b"pass2", b"salt", b"context")
+            wasm_derive_encryption_key(b"pass2", b"salt", b"context").expect("derive failed");
-            .expect("derive failed");
         assert_ne!(key, key2);
     }
 }

wasm/src/message.rs

@@ -1,10 +1,8 @@
 use wasm_bindgen::prelude::*;
 
-use mtp_codec::{
+use mtp_codec::{CommunicationType, CommunicationValue, DataType, DataTypeId, DataValue};
-    CommunicationType, CommunicationTypeId, CommunicationValue, DataType, DataTypeId, DataValue,
+use mtp_crypto::{Ed25519Signer, EncryptionType, Keyring, PublicKeyBundle, SigAlgorithm};
-};
 use mtp_type_map::communication_type_name;
-use mtp_crypto::{Ed25519Signer, EncryptionType, Keyring, SigAlgorithm};
 
 use crate::error::js_error;
 
@@ -17,8 +15,14 @@ pub fn build_ping_frame(
     data: &[u8],
 ) -> Result<Vec<u8>, JsValue> {
     let mut msg = CommunicationValue::new(CommunicationType::Ping)
-        .add_typed_default(DataType::Description, DataValue::Str(description.to_string()))
+        .add_typed_default(
-        .add_typed_default(DataType::Timestamp, DataValue::UnsignedNumber(timestamp as u128))
+            DataType::Description,
+            DataValue::Str(description.to_string()),
+        )
+        .add_typed_default(
+            DataType::Timestamp,
+            DataValue::UnsignedNumber(timestamp as u128),
+        )
         .with_sender(client_id);
 
     if !data.is_empty() {
@@ -32,13 +36,18 @@ pub fn build_ping_frame(
 /// Build a demo Ping frame with encrypted and signed containers
 /// (mirrors the Rust client example but uses only reserved data types).
 #[wasm_bindgen]
-pub fn build_demo_message(client_id: u64, keyring_bytes: &[u8]) -> Result<Vec<u8>, JsValue> {
+pub fn build_demo_message(
+    client_id: u64,
+    keyring_bytes: &[u8],
+    host_bundle_bytes: &[u8],
+) -> Result<Vec<u8>, JsValue> {
     let keyring = Keyring::from_bytes(keyring_bytes)
         .map_err(|e| js_error(&format!("invalid keyring: {}", e)))?;
 
-    // Demo encrypts to its own KEM public key (encrypt-to-self) so the roundtrip
+    // Encrypt to the server's KEM public key; the server decrypts with its keyring.
-    // is self-contained; a real client would encrypt to the server's bundle.
+    // (The client keyring only needs the Ed25519 signing key for this demo.)
-    let recipient = keyring.public_key_bundle();
+    let recipient = PublicKeyBundle::from_bytes(host_bundle_bytes)
+        .map_err(|e| js_error(&format!("invalid host bundle: {}", e)))?;
     let enc_type = EncryptionType::MlKemChaCha20Poly1305;
     let signer = Ed25519Signer::new(&keyring.sig_cl_secret_key)
         .map_err(|e| js_error(&format!("signer creation failed: {}", e)))?;
@@ -49,7 +58,8 @@ pub fn build_demo_message(client_id: u64, keyring_bytes: &[u8]) -> Result<Vec<u8
         (DataTypeId(2), DataValue::UnsignedNumber(42)),
     ]);
     let mut dv_enc = inner_enc;
-    dv_enc.encrypt_container(enc_type, &recipient, b"demo-aad")
+    dv_enc
+        .encrypt_container(enc_type, &recipient, b"demo-aad")
         .ok_or_else(|| js_error("encryption failed"))?;
 
     // Signed container
@@ -58,23 +68,40 @@ pub fn build_demo_message(client_id: u64, keyring_bytes: &[u8]) -> Result<Vec<u8
         (DataTypeId(2), DataValue::UnsignedNumber(99)),
     ]);
     let mut dv_sig = inner_sig;
-    dv_sig.sign_container(SigAlgorithm::ED25519, &signer)
+    dv_sig
+        .sign_container(SigAlgorithm::ED25519, &signer)
         .ok_or_else(|| js_error("signing failed"))?;
 
     // Signed + encrypted container
     let inner_sec = DataValue::Container(vec![
-        (DataTypeId(1), DataValue::Str("signed+encrypted payload".into())),
+        (
+            DataTypeId(1),
+            DataValue::Str("signed+encrypted payload".into()),
+        ),
         (DataTypeId(2), DataValue::UnsignedNumber(7)),
     ]);
     let mut dv_sec = inner_sec;
-    dv_sec.sign_and_encrypt_container(SigAlgorithm::ED25519, &signer, enc_type, &recipient, b"demo-aad")
+    dv_sec
+        .sign_and_encrypt_container(
+            SigAlgorithm::ED25519,
+            &signer,
+            enc_type,
+            &recipient,
+            b"demo-aad",
+        )
         .ok_or_else(|| js_error("sign+encrypt failed"))?;
 
     let timestamp = js_sys::Date::now() as u64;
 
     let msg = CommunicationValue::new(CommunicationType::Ping)
-        .add_typed_default(DataType::Description, DataValue::Str("MTP WASM Demo".into()))
+        .add_typed_default(
-        .add_typed_default(DataType::Timestamp, DataValue::UnsignedNumber(timestamp as u128))
+            DataType::Description,
+            DataValue::Str("MTP WASM Demo".into()),
+        )
+        .add_typed_default(
+            DataType::Timestamp,
+            DataValue::UnsignedNumber(timestamp as u128),
+        )
         .add_typed_default(DataType::Version, DataValue::Str("demo-wasm".into()))
         .with_sender(client_id);
 
@@ -170,7 +197,11 @@ pub fn parse_response_frame(frame: &[u8]) -> Result<String, JsValue> {
 
     let obj = js_sys::Object::new();
 
-    let _ = js_sys::Reflect::set(&obj, &JsValue::from_str("_id"), &JsValue::from(comm.get_id()));
+    let _ = js_sys::Reflect::set(
+        &obj,
+        &JsValue::from_str("_id"),
+        &JsValue::from(comm.get_id()),
+    );
 
     let type_name = communication_type_name(comm.get_type().0).unwrap_or("Unknown");
     let _ = js_sys::Reflect::set(
@@ -196,12 +227,21 @@ pub fn parse_response_frame(frame: &[u8]) -> Result<String, JsValue> {
         }
     }
 
-    let stringified = js_sys::JSON::stringify(&obj)
+    let stringified =
-        .map_err(|_| js_error("JSON stringify failed"))?;
+        js_sys::JSON::stringify(&obj).map_err(|_| js_error("JSON stringify failed"))?;
-    stringified.as_string()
+    stringified
+        .as_string()
         .ok_or_else(|| js_error("JSON stringify result not a string"))
 }
 
+/// Parse any MTP frame into the human-readable CommunicationValue display form.
+#[wasm_bindgen]
+pub fn format_frame(frame: &[u8]) -> Result<String, JsValue> {
+    let comm = CommunicationValue::from_bytes(frame)
+        .map_err(|e| js_error(&format!("parse failed: {}", e)))?;
+    Ok(comm.to_string())
+}
+
 #[cfg(test)]
 #[cfg(target_arch = "wasm32")]
 mod tests {
@@ -215,8 +255,14 @@ mod tests {
 
         assert_eq!(cv.get_type(), CommunicationTypeId(19)); // Ping
         assert_eq!(cv.get_sender(), 42);
-        assert_eq!(cv.get_data(DataTypeId(4)), &DataValue::Str("test-ping".into()));
+        assert_eq!(
-        assert_eq!(cv.get_data(DataTypeId(5)), &DataValue::UnsignedNumber(1234567890));
+            cv.get_data(DataTypeId(4)),
+            &DataValue::Str("test-ping".into())
+        );
+        assert_eq!(
+            cv.get_data(DataTypeId(5)),
+            &DataValue::UnsignedNumber(1234567890)
+        );
     }
 
     #[wasm_bindgen_test]
@@ -227,9 +273,15 @@ mod tests {
 
         assert_eq!(cv.get_type(), CommunicationTypeId(19));
         assert_eq!(cv.get_sender(), 99);
-        assert_eq!(cv.get_data(DataTypeId(4)), &DataValue::Str("with-data".into()));
+        assert_eq!(
+            cv.get_data(DataTypeId(4)),
+            &DataValue::Str("with-data".into())
+        );
         assert_eq!(cv.get_data(DataTypeId(5)), &DataValue::UnsignedNumber(555));
-        assert_eq!(cv.get_data(DataTypeId(6)), &DataValue::Bytes(payload.to_vec()));
+        assert_eq!(
+            cv.get_data(DataTypeId(6)),
+            &DataValue::Bytes(payload.to_vec())
+        );
     }
 
     #[wasm_bindgen_test]
@@ -241,12 +293,13 @@ mod tests {
 
     #[wasm_bindgen_test]
     fn build_demo_message_roundtrip() {
-        // A full keyring is required: the demo now KEM-encrypts to its own
+        // The demo KEM-encrypts to the host's bundle, so a real host keypair is
-        // public key, so the KEM keypair must be real.
+        // required; the client keyring only needs its Ed25519 signing key.
         let keyring = Keyring::generate();
         let keyring_bytes = keyring.to_bytes();
+        let host_bundle = Keyring::generate().public_key_bundle().as_bytes();
 
-        let result = build_demo_message(7, &keyring_bytes);
+        let result = build_demo_message(7, &keyring_bytes, &host_bundle);
         assert!(result.is_ok());
 
         let bytes = result.unwrap();
@@ -254,12 +307,16 @@ mod tests {
 
         assert_eq!(cv.get_type(), CommunicationTypeId(19)); // Ping
         assert_eq!(cv.get_sender(), 7);
-        assert_eq!(cv.get_data(DataTypeId(4)), &DataValue::Str("MTP WASM Demo".into()));
+        assert_eq!(
+            cv.get_data(DataTypeId(4)),
+            &DataValue::Str("MTP WASM Demo".into())
+        );
     }
 
     #[wasm_bindgen_test]
     fn build_demo_message_invalid_keyring() {
-        let result = build_demo_message(1, b"not-a-valid-keyring");
+        let host_bundle = Keyring::generate().public_key_bundle().as_bytes();
+        let result = build_demo_message(1, b"not-a-valid-keyring", &host_bundle);
         assert!(result.is_err());
         let err = result.unwrap_err();
         assert!(err.as_string().unwrap().contains("invalid keyring"));
@@ -278,11 +335,13 @@ mod tests {
         let result = parse_auth_response(&resp).expect("parse failed");
 
         let connected = js_sys::Reflect::get(&result, &"connected".into())
-            .ok().and_then(|v| v.as_bool());
+            .ok()
+            .and_then(|v| v.as_bool());
         assert_eq!(connected, Some(true));
 
         let id = js_sys::Reflect::get(&result, &"assignedId".into())
-            .ok().and_then(|v| v.as_f64());
+            .ok()
+            .and_then(|v| v.as_f64());
         assert_eq!(id, Some(42.0));
     }
 
@@ -296,7 +355,8 @@ mod tests {
         let result = parse_auth_response(&resp).expect("parse failed");
 
         let connected = js_sys::Reflect::get(&result, &"connected".into())
-            .ok().and_then(|v| v.as_bool());
+            .ok()
+            .and_then(|v| v.as_bool());
         assert_eq!(connected, Some(false));
 
         // rejected should have no assignedId

wasm/src/transport.rs

@@ -5,6 +5,8 @@ use web_sys::{WebTransport, WebTransportHash, WebTransportOptions};
 
 use crate::error::js_error;
 
+const CLOSE_FRAME_LEN: u32 = u32::MAX;
+
 /// Given a `SendStream` (old API with `.writable` or new API where stream IS a WritableStream),
 /// return the object to call `.getWriter()` on.
 fn resolve_stream_writable(send_stream: &JsValue) -> Result<JsValue, JsValue> {
@@ -199,10 +201,17 @@ impl WasmTransport {
             }
 
             if buffer.len() >= 4 {
-                let frame_len =
+                let frame_len = u32::from_be_bytes([buffer[0], buffer[1], buffer[2], buffer[3]]);
-                    u32::from_le_bytes([buffer[0], buffer[1], buffer[2], buffer[3]]) as usize;
+                if frame_len == CLOSE_FRAME_LEN {
-                if 4 + frame_len <= buffer.len() {
+                    return Err(js_error("connection closed before frame"));
-                    return Ok(buffer[4..4 + frame_len].to_vec());
+                }
+
+                let frame_len = frame_len as usize;
+                let Some(frame_end) = 4usize.checked_add(frame_len) else {
+                    return Err(js_error("invalid frame length"));
+                };
+                if frame_end <= buffer.len() {
+                    return Ok(buffer[4..frame_end].to_vec());
                 }
             }
         }
@@ -230,13 +239,7 @@ impl WasmTransport {
             let result = match read_fn.call0(&reader_val) {
                 Ok(p) => match JsFuture::from(p.unchecked_into::<js_sys::Promise>()).await {
                     Ok(v) => v,
-                    Err(e) => {
+                    Err(_) => break,
-                        let _ = on_error.call1(
-                            &JsValue::NULL,
-                            &JsValue::from_str(&format!("read stream failed: {:?}", e)),
-                        );
-                        break;
-                    }
                 },
                 Err(_) => break,
             };
@@ -302,29 +305,43 @@ impl WasmTransport {
 
             // Extract all complete frames from the buffer
             while buffer.len() >= 4 {
-                let frame_len =
+                let frame_len = u32::from_be_bytes([buffer[0], buffer[1], buffer[2], buffer[3]]);
-                    u32::from_le_bytes([buffer[0], buffer[1], buffer[2], buffer[3]]) as usize;
+                if frame_len == CLOSE_FRAME_LEN {
-                if 4 + frame_len > buffer.len() {
+                    return Ok(());
+                }
+
+                let frame_len = frame_len as usize;
+                let Some(frame_end) = 4usize.checked_add(frame_len) else {
+                    return Err(js_error("invalid frame length"));
+                };
+                if frame_end > buffer.len() {
                     break;
                 }
-                let frame = buffer[4..4 + frame_len].to_vec();
+                let frame = buffer[4..frame_end].to_vec();
                 let arr = js_sys::Uint8Array::from(&frame[..]);
                 let _ = on_message.call1(&JsValue::NULL, &arr);
-                buffer.drain(..4 + frame_len);
+                buffer.drain(..frame_end);
             }
         }
 
         // Process any remaining complete frames after stream closes
         while buffer.len() >= 4 {
-            let frame_len =
+            let frame_len = u32::from_be_bytes([buffer[0], buffer[1], buffer[2], buffer[3]]);
-                u32::from_le_bytes([buffer[0], buffer[1], buffer[2], buffer[3]]) as usize;
+            if frame_len == CLOSE_FRAME_LEN {
-            if 4 + frame_len > buffer.len() {
+                return Ok(());
+            }
+
+            let frame_len = frame_len as usize;
+            let Some(frame_end) = 4usize.checked_add(frame_len) else {
+                return Err(js_error("invalid frame length"));
+            };
+            if frame_end > buffer.len() {
                 break;
             }
-            let frame = buffer[4..4 + frame_len].to_vec();
+            let frame = buffer[4..frame_end].to_vec();
             let arr = js_sys::Uint8Array::from(&frame[..]);
             let _ = on_message.call1(&JsValue::NULL, &arr);
-            buffer.drain(..4 + frame_len);
+            buffer.drain(..frame_end);
         }
 
         Ok(())