Add support for XX noise pattern

src/crypto.rs

@@ -13,6 +13,16 @@ use snow::{
 };
 use std::convert::TryInto;
 
+/// Create a [`snow::Keypair`] from secret and public key bytes.
+/// Note: `snow::Keypair` just holds `Vec<u8>`s. So we don't check the size. But giving it the
+/// wrong size is bad.
+pub fn snow_keypair_from_secret_and_public(secret: [u8; 32], public: [u8; 32]) -> snow::Keypair {
+    snow::Keypair {
+        private: secret.to_vec(),
+        public: public.to_vec(),
+    }
+}
+
 // NB: These values come from Javascript-side
 //
 // const [NS_INITIATOR, NS_RESPONDER] = crypto.namespace('hyperswarm/secret-stream', 2)

src/error.rs

@@ -13,6 +13,12 @@ pub enum Error {
     /// Error from [`std::io`]
     #[error("{0}")]
     StdIoError(#[from] std::io::Error),
+    /// Remote public key required for IK pattern
+    #[error("IK pattern requires remote public key")]
+    MissingRemoteKey,
+    /// Remote public key not expected for XX pattern
+    #[error("XX pattern does not use remote public key at initialization")]
+    UnexpectedRemoteKey,
 }
 
 impl From<crypto_secretstream::aead::Error> for Error {

src/lib.rs

@@ -15,5 +15,7 @@ mod crypto;
 mod error;
 pub mod state_machine;
 
-pub use cipher::{Cipher, CipherIo, Event as CipherEvent};
+pub use cipher::{Cipher, CipherIo, CipherTrait, Event as CipherEvent};
+pub use crypto::snow_keypair_from_secret_and_public;
 pub use error::Error;
+pub use state_machine::{HandshakePattern, IK, XX};