Merge pull request #3028 from jkczyz/2024-04-offer-id-followups
[rust-lightning] / lightning / src / ln / peer_channel_encryptor.rs
index 071ef8a9dd6ae12b032928b646a4caf6587bcb1c..51e34bdb96967428e432cba2c8a082e1f6352b72 100644 (file)
@@ -22,10 +22,11 @@ use bitcoin::secp256k1::{PublicKey,SecretKey};
 use bitcoin::secp256k1::ecdh::SharedSecret;
 use bitcoin::secp256k1;
 
-use crate::util::chacha20poly1305rfc::ChaCha20Poly1305RFC;
-use crate::util::crypto::hkdf_extract_expand_twice;
+use hex::DisplayHex;
+
+use crate::crypto::chacha20poly1305rfc::ChaCha20Poly1305RFC;
+use crate::crypto::utils::hkdf_extract_expand_twice;
 use crate::util::ser::VecWriter;
-use bitcoin::hashes::hex::ToHex;
 
 use core::ops::Deref;
 
@@ -34,6 +35,10 @@ use core::ops::Deref;
 /// and [BOLT-1](https://github.com/lightning/bolts/blob/master/01-messaging.md#lightning-message-format):
 pub const LN_MAX_MSG_LEN: usize = ::core::u16::MAX as usize; // Must be equal to 65535
 
+/// The (rough) size buffer to pre-allocate when encoding a message. Messages should reliably be
+/// smaller than this size by at least 32 bytes or so.
+pub const MSG_BUF_ALLOC_SIZE: usize = 2048;
+
 // Sha256("Noise_XK_secp256k1_ChaChaPoly_SHA256")
 const NOISE_CK: [u8; 32] = [0x26, 0x40, 0xf5, 0x2e, 0xeb, 0xcd, 0x9e, 0x88, 0x29, 0x58, 0x95, 0x1c, 0x79, 0x42, 0x50, 0xee, 0xdb, 0x28, 0x00, 0x2c, 0x05, 0xd7, 0xdc, 0x2e, 0xa0, 0xf1, 0x95, 0x40, 0x60, 0x42, 0xca, 0xf1];
 // Sha256(NOISE_CK || "lightning")
@@ -100,7 +105,7 @@ impl PeerChannelEncryptor {
                let mut sha = Sha256::engine();
                sha.input(&NOISE_H);
                sha.input(&their_node_id.serialize()[..]);
-               let h = Sha256::from_engine(sha).into_inner();
+               let h = Sha256::from_engine(sha).to_byte_array();
 
                PeerChannelEncryptor {
                        their_node_id: Some(their_node_id),
@@ -122,7 +127,7 @@ impl PeerChannelEncryptor {
                sha.input(&NOISE_H);
                let our_node_id = node_signer.get_node_id(Recipient::Node).unwrap();
                sha.input(&our_node_id.serialize()[..]);
-               let h = Sha256::from_engine(sha).into_inner();
+               let h = Sha256::from_engine(sha).to_byte_array();
 
                PeerChannelEncryptor {
                        their_node_id: None,
@@ -165,13 +170,25 @@ impl PeerChannelEncryptor {
                res.extend_from_slice(&tag);
        }
 
+       fn decrypt_in_place_with_ad(inout: &mut [u8], n: u64, key: &[u8; 32], h: &[u8]) -> Result<(), LightningError> {
+               let mut nonce = [0; 12];
+               nonce[4..].copy_from_slice(&n.to_le_bytes()[..]);
+
+               let mut chacha = ChaCha20Poly1305RFC::new(key, &nonce, h);
+               let (inout, tag) = inout.split_at_mut(inout.len() - 16);
+               if chacha.check_decrypt_in_place(inout, tag).is_err() {
+                       return Err(LightningError{err: "Bad MAC".to_owned(), action: msgs::ErrorAction::DisconnectPeer{ msg: None }});
+               }
+               Ok(())
+       }
+
        #[inline]
        fn decrypt_with_ad(res: &mut[u8], n: u64, key: &[u8; 32], h: &[u8], cyphertext: &[u8]) -> Result<(), LightningError> {
                let mut nonce = [0; 12];
                nonce[4..].copy_from_slice(&n.to_le_bytes()[..]);
 
                let mut chacha = ChaCha20Poly1305RFC::new(key, &nonce, h);
-               if !chacha.decrypt(&cyphertext[0..cyphertext.len() - 16], res, &cyphertext[cyphertext.len() - 16..]) {
+               if chacha.variable_time_decrypt(&cyphertext[0..cyphertext.len() - 16], res, &cyphertext[cyphertext.len() - 16..]).is_err() {
                        return Err(LightningError{err: "Bad MAC".to_owned(), action: msgs::ErrorAction::DisconnectPeer{ msg: None }});
                }
                Ok(())
@@ -191,7 +208,7 @@ impl PeerChannelEncryptor {
                let mut sha = Sha256::engine();
                sha.input(&state.h);
                sha.input(&our_pub.serialize()[..]);
-               state.h = Sha256::from_engine(sha).into_inner();
+               state.h = Sha256::from_engine(sha).to_byte_array();
 
                let ss = SharedSecret::new(&their_key, &our_key);
                let temp_k = PeerChannelEncryptor::hkdf(state, ss);
@@ -203,7 +220,7 @@ impl PeerChannelEncryptor {
                let mut sha = Sha256::engine();
                sha.input(&state.h);
                sha.input(&res[34..]);
-               state.h = Sha256::from_engine(sha).into_inner();
+               state.h = Sha256::from_engine(sha).to_byte_array();
 
                (res, temp_k)
        }
@@ -219,14 +236,14 @@ impl PeerChannelEncryptor {
                }
 
                let their_pub = match PublicKey::from_slice(&act[1..34]) {
-                       Err(_) => return Err(LightningError{err: format!("Invalid public key {}", &act[1..34].to_hex()), action: msgs::ErrorAction::DisconnectPeer{ msg: None }}),
+                       Err(_) => return Err(LightningError{err: format!("Invalid public key {}", &act[1..34].as_hex()), action: msgs::ErrorAction::DisconnectPeer{ msg: None }}),
                        Ok(key) => key,
                };
 
                let mut sha = Sha256::engine();
                sha.input(&state.h);
                sha.input(&their_pub.serialize()[..]);
-               state.h = Sha256::from_engine(sha).into_inner();
+               state.h = Sha256::from_engine(sha).to_byte_array();
 
                let ss = match secret_key {
                        NoiseSecretKey::InMemory(secret_key) => SharedSecret::new(&their_pub, secret_key),
@@ -245,7 +262,7 @@ impl PeerChannelEncryptor {
                let mut sha = Sha256::engine();
                sha.input(&state.h);
                sha.input(&act[34..]);
-               state.h = Sha256::from_engine(sha).into_inner();
+               state.h = Sha256::from_engine(sha).to_byte_array();
 
                Ok((their_pub, temp_k))
        }
@@ -327,7 +344,7 @@ impl PeerChannelEncryptor {
                                                let mut sha = Sha256::engine();
                                                sha.input(&bidirectional_state.h);
                                                sha.input(&res[1..50]);
-                                               bidirectional_state.h = Sha256::from_engine(sha).into_inner();
+                                               bidirectional_state.h = Sha256::from_engine(sha).to_byte_array();
 
                                                let ss = node_signer.ecdh(Recipient::Node, &re, None).map_err(|_| LightningError {
                                                        err: "Failed to derive shared secret".to_owned(),
@@ -378,13 +395,13 @@ impl PeerChannelEncryptor {
                                                PeerChannelEncryptor::decrypt_with_ad(&mut their_node_id, 1, &temp_k2.unwrap(), &bidirectional_state.h, &act_three[1..50])?;
                                                self.their_node_id = Some(match PublicKey::from_slice(&their_node_id) {
                                                        Ok(key) => key,
-                                                       Err(_) => return Err(LightningError{err: format!("Bad node_id from peer, {}", &their_node_id.to_hex()), action: msgs::ErrorAction::DisconnectPeer{ msg: None }}),
+                                                       Err(_) => return Err(LightningError{err: format!("Bad node_id from peer, {}", &their_node_id.as_hex()), action: msgs::ErrorAction::DisconnectPeer{ msg: None }}),
                                                });
 
                                                let mut sha = Sha256::engine();
                                                sha.input(&bidirectional_state.h);
                                                sha.input(&act_three[1..50]);
-                                               bidirectional_state.h = Sha256::from_engine(sha).into_inner();
+                                               bidirectional_state.h = Sha256::from_engine(sha).to_byte_array();
 
                                                let ss = SharedSecret::new(&self.their_node_id.unwrap(), &re.unwrap());
                                                let temp_k = PeerChannelEncryptor::hkdf(bidirectional_state, ss);
@@ -411,16 +428,20 @@ impl PeerChannelEncryptor {
                Ok(self.their_node_id.unwrap().clone())
        }
 
-       /// Encrypts the given pre-serialized message, returning the encrypted version.
-       /// panics if msg.len() > 65535 or Noise handshake has not finished.
-       pub fn encrypt_buffer(&mut self, msg: &[u8]) -> Vec<u8> {
-               if msg.len() > LN_MAX_MSG_LEN {
+       /// Builds sendable bytes for a message.
+       ///
+       /// `msgbuf` must begin with 16 + 2 dummy/0 bytes, which will be filled with the encrypted
+       /// message length and its MAC. It should then be followed by the message bytes themselves
+       /// (including the two byte message type).
+       ///
+       /// For effeciency, the [`Vec::capacity`] should be at least 16 bytes larger than the
+       /// [`Vec::len`], to avoid reallocating for the message MAC, which will be appended to the vec.
+       fn encrypt_message_with_header_0s(&mut self, msgbuf: &mut Vec<u8>) {
+               let msg_len = msgbuf.len() - 16 - 2;
+               if msg_len > LN_MAX_MSG_LEN {
                        panic!("Attempted to encrypt message longer than 65535 bytes!");
                }
 
-               let mut res = Vec::with_capacity(msg.len() + 16*2 + 2);
-               res.resize(msg.len() + 16*2 + 2, 0);
-
                match self.noise_state {
                        NoiseState::Finished { ref mut sk, ref mut sn, ref mut sck, rk: _, rn: _, rck: _ } => {
                                if *sn >= 1000 {
@@ -430,16 +451,21 @@ impl PeerChannelEncryptor {
                                        *sn = 0;
                                }
 
-                               Self::encrypt_with_ad(&mut res[0..16+2], *sn, sk, &[0; 0], &(msg.len() as u16).to_be_bytes());
+                               Self::encrypt_with_ad(&mut msgbuf[0..16+2], *sn, sk, &[0; 0], &(msg_len as u16).to_be_bytes());
                                *sn += 1;
 
-                               Self::encrypt_with_ad(&mut res[16+2..], *sn, sk, &[0; 0], msg);
+                               Self::encrypt_in_place_with_ad(msgbuf, 16+2, *sn, sk, &[0; 0]);
                                *sn += 1;
                        },
                        _ => panic!("Tried to encrypt a message prior to noise handshake completion"),
                }
+       }
 
-               res
+       /// Encrypts the given pre-serialized message, returning the encrypted version.
+       /// panics if msg.len() > 65535 or Noise handshake has not finished.
+       pub fn encrypt_buffer(&mut self, mut msg: MessageBuf) -> Vec<u8> {
+               self.encrypt_message_with_header_0s(&mut msg.0);
+               msg.0
        }
 
        /// Encrypts the given message, returning the encrypted version.
@@ -448,33 +474,11 @@ impl PeerChannelEncryptor {
        pub fn encrypt_message<M: wire::Type>(&mut self, message: &M) -> Vec<u8> {
                // Allocate a buffer with 2KB, fitting most common messages. Reserve the first 16+2 bytes
                // for the 2-byte message type prefix and its MAC.
-               let mut res = VecWriter(Vec::with_capacity(2048));
+               let mut res = VecWriter(Vec::with_capacity(MSG_BUF_ALLOC_SIZE));
                res.0.resize(16 + 2, 0);
                wire::write(message, &mut res).expect("In-memory messages must never fail to serialize");
 
-               let msg_len = res.0.len() - 16 - 2;
-               if msg_len > LN_MAX_MSG_LEN {
-                       panic!("Attempted to encrypt message longer than 65535 bytes!");
-               }
-
-               match self.noise_state {
-                       NoiseState::Finished { ref mut sk, ref mut sn, ref mut sck, rk: _, rn: _, rck: _ } => {
-                               if *sn >= 1000 {
-                                       let (new_sck, new_sk) = hkdf_extract_expand_twice(sck, sk);
-                                       *sck = new_sck;
-                                       *sk = new_sk;
-                                       *sn = 0;
-                               }
-
-                               Self::encrypt_with_ad(&mut res.0[0..16+2], *sn, sk, &[0; 0], &(msg_len as u16).to_be_bytes());
-                               *sn += 1;
-
-                               Self::encrypt_in_place_with_ad(&mut res.0, 16+2, *sn, sk, &[0; 0]);
-                               *sn += 1;
-                       },
-                       _ => panic!("Tried to encrypt a message prior to noise handshake completion"),
-               }
-
+               self.encrypt_message_with_header_0s(&mut res.0);
                res.0
        }
 
@@ -501,21 +505,20 @@ impl PeerChannelEncryptor {
                }
        }
 
-       /// Decrypts the given message.
+       /// Decrypts the given message up to msg.len() - 16. Bytes after msg.len() - 16 will be left
+       /// undefined (as they contain the Poly1305 tag bytes).
+       ///
        /// panics if msg.len() > 65535 + 16
-       pub fn decrypt_message(&mut self, msg: &[u8]) -> Result<Vec<u8>, LightningError> {
+       pub fn decrypt_message(&mut self, msg: &mut [u8]) -> Result<(), LightningError> {
                if msg.len() > LN_MAX_MSG_LEN + 16 {
                        panic!("Attempted to decrypt message longer than 65535 + 16 bytes!");
                }
 
                match self.noise_state {
                        NoiseState::Finished { sk: _, sn: _, sck: _, ref rk, ref mut rn, rck: _ } => {
-                               let mut res = Vec::with_capacity(msg.len() - 16);
-                               res.resize(msg.len() - 16, 0);
-                               Self::decrypt_with_ad(&mut res[..], *rn, rk, &[0; 0], msg)?;
+                               Self::decrypt_in_place_with_ad(&mut msg[..], *rn, rk, &[0; 0])?;
                                *rn += 1;
-
-                               Ok(res)
+                               Ok(())
                        },
                        _ => panic!("Tried to decrypt a message prior to noise handshake completion"),
                }
@@ -542,52 +545,72 @@ impl PeerChannelEncryptor {
        }
 }
 
+/// A buffer which stores an encoded message (including the two message-type bytes) with some
+/// padding to allow for future encryption/MACing.
+pub struct MessageBuf(Vec<u8>);
+impl MessageBuf {
+       /// Creates a new buffer from an encoded message (i.e. the two message-type bytes followed by
+       /// the message contents).
+       ///
+       /// Panics if the message is longer than 2^16.
+       pub fn from_encoded(encoded_msg: &[u8]) -> Self {
+               if encoded_msg.len() > LN_MAX_MSG_LEN {
+                       panic!("Attempted to encrypt message longer than 65535 bytes!");
+               }
+               // In addition to the message (continaing the two message type bytes), we also have to add
+               // the message length header (and its MAC) and the message MAC.
+               let mut res = Vec::with_capacity(encoded_msg.len() + 16*2 + 2);
+               res.resize(encoded_msg.len() + 16 + 2, 0);
+               res[16 + 2..].copy_from_slice(&encoded_msg);
+               Self(res)
+       }
+}
+
 #[cfg(test)]
 mod tests {
-       use super::LN_MAX_MSG_LEN;
+       use super::{MessageBuf, LN_MAX_MSG_LEN};
 
+       use bitcoin::hashes::hex::FromHex;
        use bitcoin::secp256k1::{PublicKey, SecretKey};
        use bitcoin::secp256k1::Secp256k1;
 
-       use hex;
-
        use crate::ln::peer_channel_encryptor::{PeerChannelEncryptor,NoiseState};
        use crate::util::test_utils::TestNodeSigner;
 
        fn get_outbound_peer_for_initiator_test_vectors() -> PeerChannelEncryptor {
-               let their_node_id = PublicKey::from_slice(&hex::decode("028d7500dd4c12685d1f568b4c2b5048e8534b873319f3a8daa612b469132ec7f7").unwrap()[..]).unwrap();
+               let their_node_id = PublicKey::from_slice(&<Vec<u8>>::from_hex("028d7500dd4c12685d1f568b4c2b5048e8534b873319f3a8daa612b469132ec7f7").unwrap()[..]).unwrap();
                let secp_ctx = Secp256k1::signing_only();
 
-               let mut outbound_peer = PeerChannelEncryptor::new_outbound(their_node_id, SecretKey::from_slice(&hex::decode("1212121212121212121212121212121212121212121212121212121212121212").unwrap()[..]).unwrap());
-               assert_eq!(outbound_peer.get_act_one(&secp_ctx)[..], hex::decode("00036360e856310ce5d294e8be33fc807077dc56ac80d95d9cd4ddbd21325eff73f70df6086551151f58b8afe6c195782c6a").unwrap()[..]);
+               let mut outbound_peer = PeerChannelEncryptor::new_outbound(their_node_id, SecretKey::from_slice(&<Vec<u8>>::from_hex("1212121212121212121212121212121212121212121212121212121212121212").unwrap()[..]).unwrap());
+               assert_eq!(outbound_peer.get_act_one(&secp_ctx)[..], <Vec<u8>>::from_hex("00036360e856310ce5d294e8be33fc807077dc56ac80d95d9cd4ddbd21325eff73f70df6086551151f58b8afe6c195782c6a").unwrap()[..]);
                outbound_peer
        }
 
        fn get_inbound_peer_for_test_vectors() -> PeerChannelEncryptor {
                // transport-responder successful handshake
-               let our_node_id = SecretKey::from_slice(&hex::decode("2121212121212121212121212121212121212121212121212121212121212121").unwrap()[..]).unwrap();
-               let our_ephemeral = SecretKey::from_slice(&hex::decode("2222222222222222222222222222222222222222222222222222222222222222").unwrap()[..]).unwrap();
+               let our_node_id = SecretKey::from_slice(&<Vec<u8>>::from_hex("2121212121212121212121212121212121212121212121212121212121212121").unwrap()[..]).unwrap();
+               let our_ephemeral = SecretKey::from_slice(&<Vec<u8>>::from_hex("2222222222222222222222222222222222222222222222222222222222222222").unwrap()[..]).unwrap();
                let secp_ctx = Secp256k1::new();
                let node_signer = TestNodeSigner::new(our_node_id);
 
                let mut inbound_peer = PeerChannelEncryptor::new_inbound(&&node_signer);
 
-               let act_one = hex::decode("00036360e856310ce5d294e8be33fc807077dc56ac80d95d9cd4ddbd21325eff73f70df6086551151f58b8afe6c195782c6a").unwrap().to_vec();
-               assert_eq!(inbound_peer.process_act_one_with_keys(&act_one[..], &&node_signer, our_ephemeral.clone(), &secp_ctx).unwrap()[..], hex::decode("0002466d7fcae563e5cb09a0d1870bb580344804617879a14949cf22285f1bae3f276e2470b93aac583c9ef6eafca3f730ae").unwrap()[..]);
+               let act_one = <Vec<u8>>::from_hex("00036360e856310ce5d294e8be33fc807077dc56ac80d95d9cd4ddbd21325eff73f70df6086551151f58b8afe6c195782c6a").unwrap().to_vec();
+               assert_eq!(inbound_peer.process_act_one_with_keys(&act_one[..], &&node_signer, our_ephemeral.clone(), &secp_ctx).unwrap()[..], <Vec<u8>>::from_hex("0002466d7fcae563e5cb09a0d1870bb580344804617879a14949cf22285f1bae3f276e2470b93aac583c9ef6eafca3f730ae").unwrap()[..]);
 
-               let act_three = hex::decode("00b9e3a702e93e3a9948c2ed6e5fd7590a6e1c3a0344cfc9d5b57357049aa22355361aa02e55a8fc28fef5bd6d71ad0c38228dc68b1c466263b47fdf31e560e139ba").unwrap().to_vec();
+               let act_three = <Vec<u8>>::from_hex("00b9e3a702e93e3a9948c2ed6e5fd7590a6e1c3a0344cfc9d5b57357049aa22355361aa02e55a8fc28fef5bd6d71ad0c38228dc68b1c466263b47fdf31e560e139ba").unwrap().to_vec();
                // test vector doesn't specify the initiator static key, but it's the same as the one
                // from transport-initiator successful handshake
-               assert_eq!(inbound_peer.process_act_three(&act_three[..]).unwrap().serialize()[..], hex::decode("034f355bdcb7cc0af728ef3cceb9615d90684bb5b2ca5f859ab0f0b704075871aa").unwrap()[..]);
+               assert_eq!(inbound_peer.process_act_three(&act_three[..]).unwrap().serialize()[..], <Vec<u8>>::from_hex("034f355bdcb7cc0af728ef3cceb9615d90684bb5b2ca5f859ab0f0b704075871aa").unwrap()[..]);
 
                match inbound_peer.noise_state {
                        NoiseState::Finished { sk, sn, sck, rk, rn, rck } => {
-                               assert_eq!(sk, hex::decode("bb9020b8965f4df047e07f955f3c4b88418984aadc5cdb35096b9ea8fa5c3442").unwrap()[..]);
+                               assert_eq!(sk, <Vec<u8>>::from_hex("bb9020b8965f4df047e07f955f3c4b88418984aadc5cdb35096b9ea8fa5c3442").unwrap()[..]);
                                assert_eq!(sn, 0);
-                               assert_eq!(sck, hex::decode("919219dbb2920afa8db80f9a51787a840bcf111ed8d588caf9ab4be716e42b01").unwrap()[..]);
-                               assert_eq!(rk, hex::decode("969ab31b4d288cedf6218839b27a3e2140827047f2c0f01bf5c04435d43511a9").unwrap()[..]);
+                               assert_eq!(sck, <Vec<u8>>::from_hex("919219dbb2920afa8db80f9a51787a840bcf111ed8d588caf9ab4be716e42b01").unwrap()[..]);
+                               assert_eq!(rk, <Vec<u8>>::from_hex("969ab31b4d288cedf6218839b27a3e2140827047f2c0f01bf5c04435d43511a9").unwrap()[..]);
                                assert_eq!(rn, 0);
-                               assert_eq!(rck, hex::decode("919219dbb2920afa8db80f9a51787a840bcf111ed8d588caf9ab4be716e42b01").unwrap()[..]);
+                               assert_eq!(rck, <Vec<u8>>::from_hex("919219dbb2920afa8db80f9a51787a840bcf111ed8d588caf9ab4be716e42b01").unwrap()[..]);
                        },
                        _ => panic!()
                }
@@ -597,24 +620,24 @@ mod tests {
 
        #[test]
        fn noise_initiator_test_vectors() {
-               let our_node_id = SecretKey::from_slice(&hex::decode("1111111111111111111111111111111111111111111111111111111111111111").unwrap()[..]).unwrap();
+               let our_node_id = SecretKey::from_slice(&<Vec<u8>>::from_hex("1111111111111111111111111111111111111111111111111111111111111111").unwrap()[..]).unwrap();
                let node_signer = TestNodeSigner::new(our_node_id);
 
                {
                        // transport-initiator successful handshake
                        let mut outbound_peer = get_outbound_peer_for_initiator_test_vectors();
 
-                       let act_two = hex::decode("0002466d7fcae563e5cb09a0d1870bb580344804617879a14949cf22285f1bae3f276e2470b93aac583c9ef6eafca3f730ae").unwrap().to_vec();
-                       assert_eq!(outbound_peer.process_act_two(&act_two[..], &&node_signer).unwrap().0[..], hex::decode("00b9e3a702e93e3a9948c2ed6e5fd7590a6e1c3a0344cfc9d5b57357049aa22355361aa02e55a8fc28fef5bd6d71ad0c38228dc68b1c466263b47fdf31e560e139ba").unwrap()[..]);
+                       let act_two = <Vec<u8>>::from_hex("0002466d7fcae563e5cb09a0d1870bb580344804617879a14949cf22285f1bae3f276e2470b93aac583c9ef6eafca3f730ae").unwrap().to_vec();
+                       assert_eq!(outbound_peer.process_act_two(&act_two[..], &&node_signer).unwrap().0[..], <Vec<u8>>::from_hex("00b9e3a702e93e3a9948c2ed6e5fd7590a6e1c3a0344cfc9d5b57357049aa22355361aa02e55a8fc28fef5bd6d71ad0c38228dc68b1c466263b47fdf31e560e139ba").unwrap()[..]);
 
                        match outbound_peer.noise_state {
                                NoiseState::Finished { sk, sn, sck, rk, rn, rck } => {
-                                       assert_eq!(sk, hex::decode("969ab31b4d288cedf6218839b27a3e2140827047f2c0f01bf5c04435d43511a9").unwrap()[..]);
+                                       assert_eq!(sk, <Vec<u8>>::from_hex("969ab31b4d288cedf6218839b27a3e2140827047f2c0f01bf5c04435d43511a9").unwrap()[..]);
                                        assert_eq!(sn, 0);
-                                       assert_eq!(sck, hex::decode("919219dbb2920afa8db80f9a51787a840bcf111ed8d588caf9ab4be716e42b01").unwrap()[..]);
-                                       assert_eq!(rk, hex::decode("bb9020b8965f4df047e07f955f3c4b88418984aadc5cdb35096b9ea8fa5c3442").unwrap()[..]);
+                                       assert_eq!(sck, <Vec<u8>>::from_hex("919219dbb2920afa8db80f9a51787a840bcf111ed8d588caf9ab4be716e42b01").unwrap()[..]);
+                                       assert_eq!(rk, <Vec<u8>>::from_hex("bb9020b8965f4df047e07f955f3c4b88418984aadc5cdb35096b9ea8fa5c3442").unwrap()[..]);
                                        assert_eq!(rn, 0);
-                                       assert_eq!(rck, hex::decode("919219dbb2920afa8db80f9a51787a840bcf111ed8d588caf9ab4be716e42b01").unwrap()[..]);
+                                       assert_eq!(rck, <Vec<u8>>::from_hex("919219dbb2920afa8db80f9a51787a840bcf111ed8d588caf9ab4be716e42b01").unwrap()[..]);
                                },
                                _ => panic!()
                        }
@@ -627,7 +650,7 @@ mod tests {
                        // transport-initiator act2 bad version test
                        let mut outbound_peer = get_outbound_peer_for_initiator_test_vectors();
 
-                       let act_two = hex::decode("0102466d7fcae563e5cb09a0d1870bb580344804617879a14949cf22285f1bae3f276e2470b93aac583c9ef6eafca3f730ae").unwrap().to_vec();
+                       let act_two = <Vec<u8>>::from_hex("0102466d7fcae563e5cb09a0d1870bb580344804617879a14949cf22285f1bae3f276e2470b93aac583c9ef6eafca3f730ae").unwrap().to_vec();
                        assert!(outbound_peer.process_act_two(&act_two[..], &&node_signer).is_err());
                }
 
@@ -635,7 +658,7 @@ mod tests {
                        // transport-initiator act2 bad key serialization test
                        let mut outbound_peer = get_outbound_peer_for_initiator_test_vectors();
 
-                       let act_two = hex::decode("0004466d7fcae563e5cb09a0d1870bb580344804617879a14949cf22285f1bae3f276e2470b93aac583c9ef6eafca3f730ae").unwrap().to_vec();
+                       let act_two = <Vec<u8>>::from_hex("0004466d7fcae563e5cb09a0d1870bb580344804617879a14949cf22285f1bae3f276e2470b93aac583c9ef6eafca3f730ae").unwrap().to_vec();
                        assert!(outbound_peer.process_act_two(&act_two[..], &&node_signer).is_err());
                }
 
@@ -643,15 +666,15 @@ mod tests {
                        // transport-initiator act2 bad MAC test
                        let mut outbound_peer = get_outbound_peer_for_initiator_test_vectors();
 
-                       let act_two = hex::decode("0002466d7fcae563e5cb09a0d1870bb580344804617879a14949cf22285f1bae3f276e2470b93aac583c9ef6eafca3f730af").unwrap().to_vec();
+                       let act_two = <Vec<u8>>::from_hex("0002466d7fcae563e5cb09a0d1870bb580344804617879a14949cf22285f1bae3f276e2470b93aac583c9ef6eafca3f730af").unwrap().to_vec();
                        assert!(outbound_peer.process_act_two(&act_two[..], &&node_signer).is_err());
                }
        }
 
        #[test]
        fn noise_responder_test_vectors() {
-               let our_node_id = SecretKey::from_slice(&hex::decode("2121212121212121212121212121212121212121212121212121212121212121").unwrap()[..]).unwrap();
-               let our_ephemeral = SecretKey::from_slice(&hex::decode("2222222222222222222222222222222222222222222222222222222222222222").unwrap()[..]).unwrap();
+               let our_node_id = SecretKey::from_slice(&<Vec<u8>>::from_hex("2121212121212121212121212121212121212121212121212121212121212121").unwrap()[..]).unwrap();
+               let our_ephemeral = SecretKey::from_slice(&<Vec<u8>>::from_hex("2222222222222222222222222222222222222222222222222222222222222222").unwrap()[..]).unwrap();
                let secp_ctx = Secp256k1::new();
                let node_signer = TestNodeSigner::new(our_node_id);
 
@@ -666,31 +689,31 @@ mod tests {
                        // transport-responder act1 bad version test
                        let mut inbound_peer = PeerChannelEncryptor::new_inbound(&&node_signer);
 
-                       let act_one = hex::decode("01036360e856310ce5d294e8be33fc807077dc56ac80d95d9cd4ddbd21325eff73f70df6086551151f58b8afe6c195782c6a").unwrap().to_vec();
+                       let act_one = <Vec<u8>>::from_hex("01036360e856310ce5d294e8be33fc807077dc56ac80d95d9cd4ddbd21325eff73f70df6086551151f58b8afe6c195782c6a").unwrap().to_vec();
                        assert!(inbound_peer.process_act_one_with_keys(&act_one[..], &&node_signer, our_ephemeral.clone(), &secp_ctx).is_err());
                }
                {
                        // transport-responder act1 bad key serialization test
                        let mut inbound_peer = PeerChannelEncryptor::new_inbound(&&node_signer);
 
-                       let act_one =hex::decode("00046360e856310ce5d294e8be33fc807077dc56ac80d95d9cd4ddbd21325eff73f70df6086551151f58b8afe6c195782c6a").unwrap().to_vec();
+                       let act_one =<Vec<u8>>::from_hex("00046360e856310ce5d294e8be33fc807077dc56ac80d95d9cd4ddbd21325eff73f70df6086551151f58b8afe6c195782c6a").unwrap().to_vec();
                        assert!(inbound_peer.process_act_one_with_keys(&act_one[..], &&node_signer, our_ephemeral.clone(), &secp_ctx).is_err());
                }
                {
                        // transport-responder act1 bad MAC test
                        let mut inbound_peer = PeerChannelEncryptor::new_inbound(&&node_signer);
 
-                       let act_one = hex::decode("00036360e856310ce5d294e8be33fc807077dc56ac80d95d9cd4ddbd21325eff73f70df6086551151f58b8afe6c195782c6b").unwrap().to_vec();
+                       let act_one = <Vec<u8>>::from_hex("00036360e856310ce5d294e8be33fc807077dc56ac80d95d9cd4ddbd21325eff73f70df6086551151f58b8afe6c195782c6b").unwrap().to_vec();
                        assert!(inbound_peer.process_act_one_with_keys(&act_one[..], &&node_signer, our_ephemeral.clone(), &secp_ctx).is_err());
                }
                {
                        // transport-responder act3 bad version test
                        let mut inbound_peer = PeerChannelEncryptor::new_inbound(&&node_signer);
 
-                       let act_one = hex::decode("00036360e856310ce5d294e8be33fc807077dc56ac80d95d9cd4ddbd21325eff73f70df6086551151f58b8afe6c195782c6a").unwrap().to_vec();
-                       assert_eq!(inbound_peer.process_act_one_with_keys(&act_one[..], &&node_signer, our_ephemeral.clone(), &secp_ctx).unwrap()[..], hex::decode("0002466d7fcae563e5cb09a0d1870bb580344804617879a14949cf22285f1bae3f276e2470b93aac583c9ef6eafca3f730ae").unwrap()[..]);
+                       let act_one = <Vec<u8>>::from_hex("00036360e856310ce5d294e8be33fc807077dc56ac80d95d9cd4ddbd21325eff73f70df6086551151f58b8afe6c195782c6a").unwrap().to_vec();
+                       assert_eq!(inbound_peer.process_act_one_with_keys(&act_one[..], &&node_signer, our_ephemeral.clone(), &secp_ctx).unwrap()[..], <Vec<u8>>::from_hex("0002466d7fcae563e5cb09a0d1870bb580344804617879a14949cf22285f1bae3f276e2470b93aac583c9ef6eafca3f730ae").unwrap()[..]);
 
-                       let act_three = hex::decode("01b9e3a702e93e3a9948c2ed6e5fd7590a6e1c3a0344cfc9d5b57357049aa22355361aa02e55a8fc28fef5bd6d71ad0c38228dc68b1c466263b47fdf31e560e139ba").unwrap().to_vec();
+                       let act_three = <Vec<u8>>::from_hex("01b9e3a702e93e3a9948c2ed6e5fd7590a6e1c3a0344cfc9d5b57357049aa22355361aa02e55a8fc28fef5bd6d71ad0c38228dc68b1c466263b47fdf31e560e139ba").unwrap().to_vec();
                        assert!(inbound_peer.process_act_three(&act_three[..]).is_err());
                }
                {
@@ -701,30 +724,30 @@ mod tests {
                        // transport-responder act3 bad MAC for ciphertext test
                        let mut inbound_peer = PeerChannelEncryptor::new_inbound(&&node_signer);
 
-                       let act_one = hex::decode("00036360e856310ce5d294e8be33fc807077dc56ac80d95d9cd4ddbd21325eff73f70df6086551151f58b8afe6c195782c6a").unwrap().to_vec();
-                       assert_eq!(inbound_peer.process_act_one_with_keys(&act_one[..], &&node_signer, our_ephemeral.clone(), &secp_ctx).unwrap()[..], hex::decode("0002466d7fcae563e5cb09a0d1870bb580344804617879a14949cf22285f1bae3f276e2470b93aac583c9ef6eafca3f730ae").unwrap()[..]);
+                       let act_one = <Vec<u8>>::from_hex("00036360e856310ce5d294e8be33fc807077dc56ac80d95d9cd4ddbd21325eff73f70df6086551151f58b8afe6c195782c6a").unwrap().to_vec();
+                       assert_eq!(inbound_peer.process_act_one_with_keys(&act_one[..], &&node_signer, our_ephemeral.clone(), &secp_ctx).unwrap()[..], <Vec<u8>>::from_hex("0002466d7fcae563e5cb09a0d1870bb580344804617879a14949cf22285f1bae3f276e2470b93aac583c9ef6eafca3f730ae").unwrap()[..]);
 
-                       let act_three = hex::decode("00c9e3a702e93e3a9948c2ed6e5fd7590a6e1c3a0344cfc9d5b57357049aa22355361aa02e55a8fc28fef5bd6d71ad0c38228dc68b1c466263b47fdf31e560e139ba").unwrap().to_vec();
+                       let act_three = <Vec<u8>>::from_hex("00c9e3a702e93e3a9948c2ed6e5fd7590a6e1c3a0344cfc9d5b57357049aa22355361aa02e55a8fc28fef5bd6d71ad0c38228dc68b1c466263b47fdf31e560e139ba").unwrap().to_vec();
                        assert!(inbound_peer.process_act_three(&act_three[..]).is_err());
                }
                {
                        // transport-responder act3 bad rs test
                        let mut inbound_peer = PeerChannelEncryptor::new_inbound(&&node_signer);
 
-                       let act_one = hex::decode("00036360e856310ce5d294e8be33fc807077dc56ac80d95d9cd4ddbd21325eff73f70df6086551151f58b8afe6c195782c6a").unwrap().to_vec();
-                       assert_eq!(inbound_peer.process_act_one_with_keys(&act_one[..], &&node_signer, our_ephemeral.clone(), &secp_ctx).unwrap()[..], hex::decode("0002466d7fcae563e5cb09a0d1870bb580344804617879a14949cf22285f1bae3f276e2470b93aac583c9ef6eafca3f730ae").unwrap()[..]);
+                       let act_one = <Vec<u8>>::from_hex("00036360e856310ce5d294e8be33fc807077dc56ac80d95d9cd4ddbd21325eff73f70df6086551151f58b8afe6c195782c6a").unwrap().to_vec();
+                       assert_eq!(inbound_peer.process_act_one_with_keys(&act_one[..], &&node_signer, our_ephemeral.clone(), &secp_ctx).unwrap()[..], <Vec<u8>>::from_hex("0002466d7fcae563e5cb09a0d1870bb580344804617879a14949cf22285f1bae3f276e2470b93aac583c9ef6eafca3f730ae").unwrap()[..]);
 
-                       let act_three = hex::decode("00bfe3a702e93e3a9948c2ed6e5fd7590a6e1c3a0344cfc9d5b57357049aa2235536ad09a8ee351870c2bb7f78b754a26c6cef79a98d25139c856d7efd252c2ae73c").unwrap().to_vec();
+                       let act_three = <Vec<u8>>::from_hex("00bfe3a702e93e3a9948c2ed6e5fd7590a6e1c3a0344cfc9d5b57357049aa2235536ad09a8ee351870c2bb7f78b754a26c6cef79a98d25139c856d7efd252c2ae73c").unwrap().to_vec();
                        assert!(inbound_peer.process_act_three(&act_three[..]).is_err());
                }
                {
                        // transport-responder act3 bad MAC test
                        let mut inbound_peer = PeerChannelEncryptor::new_inbound(&&node_signer);
 
-                       let act_one = hex::decode("00036360e856310ce5d294e8be33fc807077dc56ac80d95d9cd4ddbd21325eff73f70df6086551151f58b8afe6c195782c6a").unwrap().to_vec();
-                       assert_eq!(inbound_peer.process_act_one_with_keys(&act_one[..], &&node_signer, our_ephemeral.clone(), &secp_ctx).unwrap()[..], hex::decode("0002466d7fcae563e5cb09a0d1870bb580344804617879a14949cf22285f1bae3f276e2470b93aac583c9ef6eafca3f730ae").unwrap()[..]);
+                       let act_one = <Vec<u8>>::from_hex("00036360e856310ce5d294e8be33fc807077dc56ac80d95d9cd4ddbd21325eff73f70df6086551151f58b8afe6c195782c6a").unwrap().to_vec();
+                       assert_eq!(inbound_peer.process_act_one_with_keys(&act_one[..], &&node_signer, our_ephemeral.clone(), &secp_ctx).unwrap()[..], <Vec<u8>>::from_hex("0002466d7fcae563e5cb09a0d1870bb580344804617879a14949cf22285f1bae3f276e2470b93aac583c9ef6eafca3f730ae").unwrap()[..]);
 
-                       let act_three = hex::decode("00b9e3a702e93e3a9948c2ed6e5fd7590a6e1c3a0344cfc9d5b57357049aa22355361aa02e55a8fc28fef5bd6d71ad0c38228dc68b1c466263b47fdf31e560e139bb").unwrap().to_vec();
+                       let act_three = <Vec<u8>>::from_hex("00b9e3a702e93e3a9948c2ed6e5fd7590a6e1c3a0344cfc9d5b57357049aa22355361aa02e55a8fc28fef5bd6d71ad0c38228dc68b1c466263b47fdf31e560e139bb").unwrap().to_vec();
                        assert!(inbound_peer.process_act_three(&act_three[..]).is_err());
                }
        }
@@ -737,20 +760,20 @@ mod tests {
                let mut outbound_peer = get_outbound_peer_for_initiator_test_vectors();
 
                {
-                       let our_node_id = SecretKey::from_slice(&hex::decode("1111111111111111111111111111111111111111111111111111111111111111").unwrap()[..]).unwrap();
+                       let our_node_id = SecretKey::from_slice(&<Vec<u8>>::from_hex("1111111111111111111111111111111111111111111111111111111111111111").unwrap()[..]).unwrap();
                        let node_signer = TestNodeSigner::new(our_node_id);
 
-                       let act_two = hex::decode("0002466d7fcae563e5cb09a0d1870bb580344804617879a14949cf22285f1bae3f276e2470b93aac583c9ef6eafca3f730ae").unwrap().to_vec();
-                       assert_eq!(outbound_peer.process_act_two(&act_two[..], &&node_signer).unwrap().0[..], hex::decode("00b9e3a702e93e3a9948c2ed6e5fd7590a6e1c3a0344cfc9d5b57357049aa22355361aa02e55a8fc28fef5bd6d71ad0c38228dc68b1c466263b47fdf31e560e139ba").unwrap()[..]);
+                       let act_two = <Vec<u8>>::from_hex("0002466d7fcae563e5cb09a0d1870bb580344804617879a14949cf22285f1bae3f276e2470b93aac583c9ef6eafca3f730ae").unwrap().to_vec();
+                       assert_eq!(outbound_peer.process_act_two(&act_two[..], &&node_signer).unwrap().0[..], <Vec<u8>>::from_hex("00b9e3a702e93e3a9948c2ed6e5fd7590a6e1c3a0344cfc9d5b57357049aa22355361aa02e55a8fc28fef5bd6d71ad0c38228dc68b1c466263b47fdf31e560e139ba").unwrap()[..]);
 
                        match outbound_peer.noise_state {
                                NoiseState::Finished { sk, sn, sck, rk, rn, rck } => {
-                                       assert_eq!(sk, hex::decode("969ab31b4d288cedf6218839b27a3e2140827047f2c0f01bf5c04435d43511a9").unwrap()[..]);
+                                       assert_eq!(sk, <Vec<u8>>::from_hex("969ab31b4d288cedf6218839b27a3e2140827047f2c0f01bf5c04435d43511a9").unwrap()[..]);
                                        assert_eq!(sn, 0);
-                                       assert_eq!(sck, hex::decode("919219dbb2920afa8db80f9a51787a840bcf111ed8d588caf9ab4be716e42b01").unwrap()[..]);
-                                       assert_eq!(rk, hex::decode("bb9020b8965f4df047e07f955f3c4b88418984aadc5cdb35096b9ea8fa5c3442").unwrap()[..]);
+                                       assert_eq!(sck, <Vec<u8>>::from_hex("919219dbb2920afa8db80f9a51787a840bcf111ed8d588caf9ab4be716e42b01").unwrap()[..]);
+                                       assert_eq!(rk, <Vec<u8>>::from_hex("bb9020b8965f4df047e07f955f3c4b88418984aadc5cdb35096b9ea8fa5c3442").unwrap()[..]);
                                        assert_eq!(rn, 0);
-                                       assert_eq!(rck, hex::decode("919219dbb2920afa8db80f9a51787a840bcf111ed8d588caf9ab4be716e42b01").unwrap()[..]);
+                                       assert_eq!(rck, <Vec<u8>>::from_hex("919219dbb2920afa8db80f9a51787a840bcf111ed8d588caf9ab4be716e42b01").unwrap()[..]);
                                },
                                _ => panic!()
                        }
@@ -760,26 +783,28 @@ mod tests {
 
                for i in 0..1005 {
                        let msg = [0x68, 0x65, 0x6c, 0x6c, 0x6f];
-                       let res = outbound_peer.encrypt_buffer(&msg);
+                       let mut res = outbound_peer.encrypt_buffer(MessageBuf::from_encoded(&msg));
                        assert_eq!(res.len(), 5 + 2*16 + 2);
 
                        let len_header = res[0..2+16].to_vec();
                        assert_eq!(inbound_peer.decrypt_length_header(&len_header[..]).unwrap() as usize, msg.len());
-                       assert_eq!(inbound_peer.decrypt_message(&res[2+16..]).unwrap()[..], msg[..]);
 
                        if i == 0 {
-                               assert_eq!(res, hex::decode("cf2b30ddf0cf3f80e7c35a6e6730b59fe802473180f396d88a8fb0db8cbcf25d2f214cf9ea1d95").unwrap());
+                               assert_eq!(res, <Vec<u8>>::from_hex("cf2b30ddf0cf3f80e7c35a6e6730b59fe802473180f396d88a8fb0db8cbcf25d2f214cf9ea1d95").unwrap());
                        } else if i == 1 {
-                               assert_eq!(res, hex::decode("72887022101f0b6753e0c7de21657d35a4cb2a1f5cde2650528bbc8f837d0f0d7ad833b1a256a1").unwrap());
+                               assert_eq!(res, <Vec<u8>>::from_hex("72887022101f0b6753e0c7de21657d35a4cb2a1f5cde2650528bbc8f837d0f0d7ad833b1a256a1").unwrap());
                        } else if i == 500 {
-                               assert_eq!(res, hex::decode("178cb9d7387190fa34db9c2d50027d21793c9bc2d40b1e14dcf30ebeeeb220f48364f7a4c68bf8").unwrap());
+                               assert_eq!(res, <Vec<u8>>::from_hex("178cb9d7387190fa34db9c2d50027d21793c9bc2d40b1e14dcf30ebeeeb220f48364f7a4c68bf8").unwrap());
                        } else if i == 501 {
-                               assert_eq!(res, hex::decode("1b186c57d44eb6de4c057c49940d79bb838a145cb528d6e8fd26dbe50a60ca2c104b56b60e45bd").unwrap());
+                               assert_eq!(res, <Vec<u8>>::from_hex("1b186c57d44eb6de4c057c49940d79bb838a145cb528d6e8fd26dbe50a60ca2c104b56b60e45bd").unwrap());
                        } else if i == 1000 {
-                               assert_eq!(res, hex::decode("4a2f3cc3b5e78ddb83dcb426d9863d9d9a723b0337c89dd0b005d89f8d3c05c52b76b29b740f09").unwrap());
+                               assert_eq!(res, <Vec<u8>>::from_hex("4a2f3cc3b5e78ddb83dcb426d9863d9d9a723b0337c89dd0b005d89f8d3c05c52b76b29b740f09").unwrap());
                        } else if i == 1001 {
-                               assert_eq!(res, hex::decode("2ecd8c8a5629d0d02ab457a0fdd0f7b90a192cd46be5ecb6ca570bfc5e268338b1a16cf4ef2d36").unwrap());
+                               assert_eq!(res, <Vec<u8>>::from_hex("2ecd8c8a5629d0d02ab457a0fdd0f7b90a192cd46be5ecb6ca570bfc5e268338b1a16cf4ef2d36").unwrap());
                        }
+
+                       inbound_peer.decrypt_message(&mut res[2+16..]).unwrap();
+                       assert_eq!(res[2 + 16..res.len() - 16], msg[..]);
                }
        }
 
@@ -794,7 +819,7 @@ mod tests {
        fn max_message_len_encryption() {
                let mut outbound_peer = get_outbound_peer_for_initiator_test_vectors();
                let msg = [4u8; LN_MAX_MSG_LEN + 1];
-               outbound_peer.encrypt_buffer(&msg);
+               outbound_peer.encrypt_buffer(MessageBuf::from_encoded(&msg));
        }
 
        #[test]
@@ -803,7 +828,7 @@ mod tests {
                let mut inbound_peer = get_inbound_peer_for_test_vectors();
 
                // MSG should not exceed LN_MAX_MSG_LEN + 16
-               let msg = [4u8; LN_MAX_MSG_LEN + 17];
-               inbound_peer.decrypt_message(&msg).unwrap();
+               let mut msg = [4u8; LN_MAX_MSG_LEN + 17];
+               inbound_peer.decrypt_message(&mut msg).unwrap();
        }
 }