General & Crypto

crypto/src/aead.rs

@@ -0,0 +1,171 @@
+use crate::error::CryptoError;
+
+#[cfg(any(feature = "chacha20poly1305", feature = "aes-gcm"))]
+use rand_core::OsRng;
+
+#[cfg(any(feature = "chacha20poly1305", feature = "aes-gcm"))]
+use rand_core::RngCore;
+
+pub trait AeadEncrypt {
+    fn encrypt(&self, plaintext: &[u8], aad: &[u8]) -> Result<Vec<u8>, CryptoError>;
+}
+
+pub trait AeadDecrypt {
+    fn decrypt(&self, ciphertext: &[u8], aad: &[u8]) -> Result<Vec<u8>, CryptoError>;
+}
+
+pub trait AeadCipher: AeadEncrypt + AeadDecrypt {
+    fn key_size() -> usize;
+}
+
+#[cfg(feature = "chacha20poly1305")]
+pub struct ChaCha20Poly1305 {
+    key: [u8; 32],
+}
+
+#[cfg(feature = "chacha20poly1305")]
+impl ChaCha20Poly1305 {
+    pub fn new(key: [u8; 32]) -> Self {
+        Self { key }
+    }
+}
+
+#[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;
+
+        let key = chacha20poly1305::Key::from_slice(&self.key);
+        let cipher = XChaCha20Poly1305::new(key);
+
+        let mut nonce = [0u8; 24];
+        OsRng.fill_bytes(&mut nonce);
+        let nonce_ref = XNonce::from_slice(&nonce);
+
+        let payload = Payload {
+            msg: plaintext,
+            aad,
+        };
+
+        let mut ciphertext = cipher
+            .encrypt(nonce_ref, payload)
+            .map_err(|_| CryptoError::EncryptionFailed)?;
+
+        let mut out = Vec::with_capacity(nonce.len() + ciphertext.len());
+        out.extend_from_slice(&nonce);
+        out.append(&mut ciphertext);
+        Ok(out)
+    }
+}
+
+#[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;
+
+        if ciphertext.len() < 24 {
+            return Err(CryptoError::InvalidNonceLength);
+        }
+
+        let (nonce, ct) = ciphertext.split_at(24);
+        let key = chacha20poly1305::Key::from_slice(&self.key);
+        let cipher = XChaCha20Poly1305::new(key);
+        let nonce_ref = XNonce::from_slice(nonce);
+
+        let payload = Payload {
+            msg: ct,
+            aad,
+        };
+
+        cipher
+            .decrypt(nonce_ref, payload)
+            .map_err(|_| CryptoError::DecryptionFailed)
+    }
+}
+
+#[cfg(feature = "chacha20poly1305")]
+impl AeadCipher for ChaCha20Poly1305 {
+    fn key_size() -> usize {
+        32
+    }
+}
+
+#[cfg(feature = "aes-gcm")]
+pub struct Aes256Gcm {
+    key: [u8; 32],
+}
+
+#[cfg(feature = "aes-gcm")]
+impl Aes256Gcm {
+    pub fn new(key: [u8; 32]) -> Self {
+        Self { key }
+    }
+}
+
+#[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;
+
+        let key = aes_gcm::Key::<AesGcmInner>::from_slice(&self.key);
+        let cipher = AesGcmInner::new(key);
+
+        let mut nonce = [0u8; 12];
+        OsRng.fill_bytes(&mut nonce);
+        let nonce_ref = Nonce::from_slice(&nonce);
+
+        let payload = Payload {
+            msg: plaintext,
+            aad,
+        };
+
+        let mut ciphertext = cipher
+            .encrypt(nonce_ref, payload)
+            .map_err(|_| CryptoError::EncryptionFailed)?;
+
+        let mut out = Vec::with_capacity(nonce.len() + ciphertext.len());
+        out.extend_from_slice(&nonce);
+        out.append(&mut ciphertext);
+        Ok(out)
+    }
+}
+
+#[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;
+
+        if ciphertext.len() < 12 {
+            return Err(CryptoError::InvalidNonceLength);
+        }
+
+        let (nonce, ct) = ciphertext.split_at(12);
+        let key = aes_gcm::Key::<AesGcmInner>::from_slice(&self.key);
+        let cipher = AesGcmInner::new(key);
+        let nonce_ref = Nonce::from_slice(nonce);
+
+        let payload = Payload {
+            msg: ct,
+            aad,
+        };
+
+        cipher
+            .decrypt(nonce_ref, payload)
+            .map_err(|_| CryptoError::DecryptionFailed)
+    }
+}
+
+#[cfg(feature = "aes-gcm")]
+impl AeadCipher for Aes256Gcm {
+    fn key_size() -> usize {
+        32
+    }
+}