Move OPAQUE into Iota and harden password authentication

iota-opaque/src/credential/aad.rs

@@ -0,0 +1,23 @@
+use super::CredentialError;
+use crate::opaque::CURRENT_OPAQUE_PROFILE;
+
+#[derive(Clone, Copy)]
+pub struct CredentialBindingV1<'a> {
+    pub principal: &'a str,
+    pub iota_id: i64,
+    pub account_public_key_sha256: &'a [u8; 32],
+}
+
+pub(crate) fn associated_data(
+    binding: &CredentialBindingV1<'_>,
+) -> Result<Vec<u8>, CredentialError> {
+    let principal = binding.principal.as_bytes();
+    let length = u32::try_from(principal.len()).map_err(|_| CredentialError::FieldTooLarge)?;
+    let mut output = b"tensamin:opaque-credential-aad:v1\0".to_vec();
+    output.extend_from_slice(&CURRENT_OPAQUE_PROFILE.to_be_bytes());
+    output.extend_from_slice(&length.to_be_bytes());
+    output.extend_from_slice(principal);
+    output.extend_from_slice(&binding.iota_id.to_be_bytes());
+    output.extend_from_slice(binding.account_public_key_sha256);
+    Ok(output)
+}