_ Git - rust-lightning/blob - lightning/src/ln/peer_channel_encryptor.rs

   1 // This file is Copyright its original authors, visible in version control
   2 // history.
   3 //
   4 // This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
   5 // or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   6 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
   7 // You may not use this file except in accordance with one or both of these
   8 // licenses.
   9
  10 use crate::prelude::*;
  11
  12 use crate::sign::{NodeSigner, Recipient};
  13 use crate::ln::msgs::LightningError;
  14 use crate::ln::msgs;
  15 use crate::ln::wire;
  16
  17 use bitcoin::hashes::{Hash, HashEngine};
  18 use bitcoin::hashes::sha256::Hash as Sha256;
  19
  20 use bitcoin::secp256k1::Secp256k1;
  21 use bitcoin::secp256k1::{PublicKey,SecretKey};
  22 use bitcoin::secp256k1::ecdh::SharedSecret;
  23 use bitcoin::secp256k1;
  24
  25 use crate::util::chacha20poly1305rfc::ChaCha20Poly1305RFC;
  26 use crate::util::crypto::hkdf_extract_expand_twice;
  27 use crate::util::ser::VecWriter;
  28 use bitcoin::hashes::hex::ToHex;
  29
  30 use core::ops::Deref;
  31
  32 /// Maximum Lightning message data length according to
  33 /// [BOLT-8](https://github.com/lightning/bolts/blob/v1.0/08-transport.md#lightning-message-specification)
  34 /// and [BOLT-1](https://github.com/lightning/bolts/blob/master/01-messaging.md#lightning-message-format):
  35 pub const LN_MAX_MSG_LEN: usize = ::core::u16::MAX as usize; // Must be equal to 65535
  36
  37 /// The (rough) size buffer to pre-allocate when encoding a message. Messages should reliably be
  38 /// smaller than this size by at least 32 bytes or so.
  39 pub const MSG_BUF_ALLOC_SIZE: usize = 2048;
  40
  41 // Sha256("Noise_XK_secp256k1_ChaChaPoly_SHA256")
  42 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];
  43 // Sha256(NOISE_CK || "lightning")
  44 const NOISE_H: [u8; 32] = [0xd1, 0xfb, 0xf6, 0xde, 0xe4, 0xf6, 0x86, 0xf1, 0x32, 0xfd, 0x70, 0x2c, 0x4a, 0xbf, 0x8f, 0xba, 0x4b, 0xb4, 0x20, 0xd8, 0x9d, 0x2a, 0x04, 0x8a, 0x3c, 0x4f, 0x4c, 0x09, 0x2e, 0x37, 0xb6, 0x76];
  45
  46 enum NoiseSecretKey<'a, 'b, NS: Deref> where NS::Target: NodeSigner {
  47         InMemory(&'a SecretKey),
  48         NodeSigner(&'b NS)
  49 }
  50
  51 pub enum NextNoiseStep {
  52         ActOne,
  53         ActTwo,
  54         ActThree,
  55         NoiseComplete,
  56 }
  57
  58 #[derive(PartialEq)]
  59 enum NoiseStep {
  60         PreActOne,
  61         PostActOne,
  62         PostActTwo,
  63         // When done swap noise_state for NoiseState::Finished
  64 }
  65
  66 struct BidirectionalNoiseState {
  67         h: [u8; 32],
  68         ck: [u8; 32],
  69 }
  70 enum DirectionalNoiseState {
  71         Outbound {
  72                 ie: SecretKey,
  73         },
  74         Inbound {
  75                 ie: Option<PublicKey>, // filled in if state >= PostActOne
  76                 re: Option<SecretKey>, // filled in if state >= PostActTwo
  77                 temp_k2: Option<[u8; 32]>, // filled in if state >= PostActTwo
  78         }
  79 }
  80 enum NoiseState {
  81         InProgress {
  82                 state: NoiseStep,
  83                 directional_state: DirectionalNoiseState,
  84                 bidirectional_state: BidirectionalNoiseState,
  85         },
  86         Finished {
  87                 sk: [u8; 32],
  88                 sn: u64,
  89                 sck: [u8; 32],
  90                 rk: [u8; 32],
  91                 rn: u64,
  92                 rck: [u8; 32],
  93         }
  94 }
  95
  96 pub struct PeerChannelEncryptor {
  97         their_node_id: Option<PublicKey>, // filled in for outbound, or inbound after noise_state is Finished
  98
  99         noise_state: NoiseState,
 100 }
 101
 102 impl PeerChannelEncryptor {
 103         pub fn new_outbound(their_node_id: PublicKey, ephemeral_key: SecretKey) -> PeerChannelEncryptor {
 104                 let mut sha = Sha256::engine();
 105                 sha.input(&NOISE_H);
 106                 sha.input(&their_node_id.serialize()[..]);
 107                 let h = Sha256::from_engine(sha).into_inner();
 108
 109                 PeerChannelEncryptor {
 110                         their_node_id: Some(their_node_id),
 111                         noise_state: NoiseState::InProgress {
 112                                 state: NoiseStep::PreActOne,
 113                                 directional_state: DirectionalNoiseState::Outbound {
 114                                         ie: ephemeral_key,
 115                                 },
 116                                 bidirectional_state: BidirectionalNoiseState {
 117                                         h,
 118                                         ck: NOISE_CK,
 119                                 },
 120                         }
 121                 }
 122         }
 123
 124         pub fn new_inbound<NS: Deref>(node_signer: &NS) -> PeerChannelEncryptor where NS::Target: NodeSigner {
 125                 let mut sha = Sha256::engine();
 126                 sha.input(&NOISE_H);
 127                 let our_node_id = node_signer.get_node_id(Recipient::Node).unwrap();
 128                 sha.input(&our_node_id.serialize()[..]);
 129                 let h = Sha256::from_engine(sha).into_inner();
 130
 131                 PeerChannelEncryptor {
 132                         their_node_id: None,
 133                         noise_state: NoiseState::InProgress {
 134                                 state: NoiseStep::PreActOne,
 135                                 directional_state: DirectionalNoiseState::Inbound {
 136                                         ie: None,
 137                                         re: None,
 138                                         temp_k2: None,
 139                                 },
 140                                 bidirectional_state: BidirectionalNoiseState {
 141                                         h,
 142                                         ck: NOISE_CK,
 143                                 },
 144                         }
 145                 }
 146         }
 147
 148         #[inline]
 149         fn encrypt_with_ad(res: &mut[u8], n: u64, key: &[u8; 32], h: &[u8], plaintext: &[u8]) {
 150                 let mut nonce = [0; 12];
 151                 nonce[4..].copy_from_slice(&n.to_le_bytes()[..]);
 152
 153                 let mut chacha = ChaCha20Poly1305RFC::new(key, &nonce, h);
 154                 let mut tag = [0; 16];
 155                 chacha.encrypt(plaintext, &mut res[0..plaintext.len()], &mut tag);
 156                 res[plaintext.len()..].copy_from_slice(&tag);
 157         }
 158
 159         #[inline]
 160         /// Encrypts the message in res[offset..] in-place and pushes a 16-byte tag onto the end of
 161         /// res.
 162         fn encrypt_in_place_with_ad(res: &mut Vec<u8>, offset: usize, n: u64, key: &[u8; 32], h: &[u8]) {
 163                 let mut nonce = [0; 12];
 164                 nonce[4..].copy_from_slice(&n.to_le_bytes()[..]);
 165
 166                 let mut chacha = ChaCha20Poly1305RFC::new(key, &nonce, h);
 167                 let mut tag = [0; 16];
 168                 chacha.encrypt_full_message_in_place(&mut res[offset..], &mut tag);
 169                 res.extend_from_slice(&tag);
 170         }
 171
 172         #[inline]
 173         fn decrypt_with_ad(res: &mut[u8], n: u64, key: &[u8; 32], h: &[u8], cyphertext: &[u8]) -> Result<(), LightningError> {
 174                 let mut nonce = [0; 12];
 175                 nonce[4..].copy_from_slice(&n.to_le_bytes()[..]);
 176
 177                 let mut chacha = ChaCha20Poly1305RFC::new(key, &nonce, h);
 178                 if !chacha.decrypt(&cyphertext[0..cyphertext.len() - 16], res, &cyphertext[cyphertext.len() - 16..]) {
 179                         return Err(LightningError{err: "Bad MAC".to_owned(), action: msgs::ErrorAction::DisconnectPeer{ msg: None }});
 180                 }
 181                 Ok(())
 182         }
 183
 184         #[inline]
 185         fn hkdf(state: &mut BidirectionalNoiseState, ss: SharedSecret) -> [u8; 32] {
 186                 let (t1, t2) = hkdf_extract_expand_twice(&state.ck, ss.as_ref());
 187                 state.ck = t1;
 188                 t2
 189         }
 190
 191         #[inline]
 192         fn outbound_noise_act<T: secp256k1::Signing>(secp_ctx: &Secp256k1<T>, state: &mut BidirectionalNoiseState, our_key: &SecretKey, their_key: &PublicKey) -> ([u8; 50], [u8; 32]) {
 193                 let our_pub = PublicKey::from_secret_key(secp_ctx, &our_key);
 194
 195                 let mut sha = Sha256::engine();
 196                 sha.input(&state.h);
 197                 sha.input(&our_pub.serialize()[..]);
 198                 state.h = Sha256::from_engine(sha).into_inner();
 199
 200                 let ss = SharedSecret::new(&their_key, &our_key);
 201                 let temp_k = PeerChannelEncryptor::hkdf(state, ss);
 202
 203                 let mut res = [0; 50];
 204                 res[1..34].copy_from_slice(&our_pub.serialize()[..]);
 205                 PeerChannelEncryptor::encrypt_with_ad(&mut res[34..], 0, &temp_k, &state.h, &[0; 0]);
 206
 207                 let mut sha = Sha256::engine();
 208                 sha.input(&state.h);
 209                 sha.input(&res[34..]);
 210                 state.h = Sha256::from_engine(sha).into_inner();
 211
 212                 (res, temp_k)
 213         }
 214
 215         #[inline]
 216         fn inbound_noise_act<'a, 'b, NS: Deref>(
 217                 state: &mut BidirectionalNoiseState, act: &[u8], secret_key: NoiseSecretKey<'a, 'b, NS>
 218         ) -> Result<(PublicKey, [u8; 32]), LightningError> where NS::Target: NodeSigner {
 219                 assert_eq!(act.len(), 50);
 220
 221                 if act[0] != 0 {
 222                         return Err(LightningError{err: format!("Unknown handshake version number {}", act[0]), action: msgs::ErrorAction::DisconnectPeer{ msg: None }});
 223                 }
 224
 225                 let their_pub = match PublicKey::from_slice(&act[1..34]) {
 226                         Err(_) => return Err(LightningError{err: format!("Invalid public key {}", &act[1..34].to_hex()), action: msgs::ErrorAction::DisconnectPeer{ msg: None }}),
 227                         Ok(key) => key,
 228                 };
 229
 230                 let mut sha = Sha256::engine();
 231                 sha.input(&state.h);
 232                 sha.input(&their_pub.serialize()[..]);
 233                 state.h = Sha256::from_engine(sha).into_inner();
 234
 235                 let ss = match secret_key {
 236                         NoiseSecretKey::InMemory(secret_key) => SharedSecret::new(&their_pub, secret_key),
 237                         NoiseSecretKey::NodeSigner(node_signer) => node_signer
 238                                 .ecdh(Recipient::Node, &their_pub, None)
 239                                 .map_err(|_| LightningError {
 240                                         err: "Failed to derive shared secret".to_owned(),
 241                                         action: msgs::ErrorAction::DisconnectPeer { msg: None }
 242                                 })?,
 243                 };
 244                 let temp_k = PeerChannelEncryptor::hkdf(state, ss);
 245
 246                 let mut dec = [0; 0];
 247                 PeerChannelEncryptor::decrypt_with_ad(&mut dec, 0, &temp_k, &state.h, &act[34..])?;
 248
 249                 let mut sha = Sha256::engine();
 250                 sha.input(&state.h);
 251                 sha.input(&act[34..]);
 252                 state.h = Sha256::from_engine(sha).into_inner();
 253
 254                 Ok((their_pub, temp_k))
 255         }
 256
 257         pub fn get_act_one<C: secp256k1::Signing>(&mut self, secp_ctx: &Secp256k1<C>) -> [u8; 50] {
 258                 match self.noise_state {
 259                         NoiseState::InProgress { ref mut state, ref directional_state, ref mut bidirectional_state } =>
 260                                 match directional_state {
 261                                         &DirectionalNoiseState::Outbound { ref ie } => {
 262                                                 if *state != NoiseStep::PreActOne {
 263                                                         panic!("Requested act at wrong step");
 264                                                 }
 265
 266                                                 let (res, _) = PeerChannelEncryptor::outbound_noise_act(secp_ctx, bidirectional_state, &ie, &self.their_node_id.unwrap());
 267                                                 *state = NoiseStep::PostActOne;
 268                                                 res
 269                                         },
 270                                         _ => panic!("Wrong direction for act"),
 271                                 },
 272                         _ => panic!("Cannot get act one after noise handshake completes"),
 273                 }
 274         }
 275
 276         pub fn process_act_one_with_keys<C: secp256k1::Signing, NS: Deref>(
 277                 &mut self, act_one: &[u8], node_signer: &NS, our_ephemeral: SecretKey, secp_ctx: &Secp256k1<C>)
 278         -> Result<[u8; 50], LightningError> where NS::Target: NodeSigner {
 279                 assert_eq!(act_one.len(), 50);
 280
 281                 match self.noise_state {
 282                         NoiseState::InProgress { ref mut state, ref mut directional_state, ref mut bidirectional_state } =>
 283                                 match directional_state {
 284                                         &mut DirectionalNoiseState::Inbound { ref mut ie, ref mut re, ref mut temp_k2 } => {
 285                                                 if *state != NoiseStep::PreActOne {
 286                                                         panic!("Requested act at wrong step");
 287                                                 }
 288
 289                                                 let (their_pub, _) = PeerChannelEncryptor::inbound_noise_act(bidirectional_state, act_one, NoiseSecretKey::NodeSigner(node_signer))?;
 290                                                 ie.get_or_insert(their_pub);
 291
 292                                                 re.get_or_insert(our_ephemeral);
 293
 294                                                 let (res, temp_k) =
 295                                                         PeerChannelEncryptor::outbound_noise_act(secp_ctx, bidirectional_state, &re.unwrap(), &ie.unwrap());
 296                                                 *temp_k2 = Some(temp_k);
 297                                                 *state = NoiseStep::PostActTwo;
 298                                                 Ok(res)
 299                                         },
 300                                         _ => panic!("Wrong direction for act"),
 301                                 },
 302                         _ => panic!("Cannot get act one after noise handshake completes"),
 303                 }
 304         }
 305
 306         pub fn process_act_two<NS: Deref>(
 307                 &mut self, act_two: &[u8], node_signer: &NS)
 308         -> Result<([u8; 66], PublicKey), LightningError> where NS::Target: NodeSigner {
 309                 assert_eq!(act_two.len(), 50);
 310
 311                 let final_hkdf;
 312                 let ck;
 313                 let res: [u8; 66] = match self.noise_state {
 314                         NoiseState::InProgress { ref state, ref directional_state, ref mut bidirectional_state } =>
 315                                 match directional_state {
 316                                         &DirectionalNoiseState::Outbound { ref ie } => {
 317                                                 if *state != NoiseStep::PostActOne {
 318                                                         panic!("Requested act at wrong step");
 319                                                 }
 320
 321                                                 let (re, temp_k2) = PeerChannelEncryptor::inbound_noise_act(bidirectional_state, act_two, NoiseSecretKey::<NS>::InMemory(&ie))?;
 322
 323                                                 let mut res = [0; 66];
 324                                                 let our_node_id = node_signer.get_node_id(Recipient::Node).map_err(|_| LightningError {
 325                                                         err: "Failed to encrypt message".to_owned(),
 326                                                         action: msgs::ErrorAction::DisconnectPeer { msg: None }
 327                                                 })?;
 328
 329                                                 PeerChannelEncryptor::encrypt_with_ad(&mut res[1..50], 1, &temp_k2, &bidirectional_state.h, &our_node_id.serialize()[..]);
 330
 331                                                 let mut sha = Sha256::engine();
 332                                                 sha.input(&bidirectional_state.h);
 333                                                 sha.input(&res[1..50]);
 334                                                 bidirectional_state.h = Sha256::from_engine(sha).into_inner();
 335
 336                                                 let ss = node_signer.ecdh(Recipient::Node, &re, None).map_err(|_| LightningError {
 337                                                         err: "Failed to derive shared secret".to_owned(),
 338                                                         action: msgs::ErrorAction::DisconnectPeer { msg: None }
 339                                                 })?;
 340                                                 let temp_k = PeerChannelEncryptor::hkdf(bidirectional_state, ss);
 341
 342                                                 PeerChannelEncryptor::encrypt_with_ad(&mut res[50..], 0, &temp_k, &bidirectional_state.h, &[0; 0]);
 343                                                 final_hkdf = hkdf_extract_expand_twice(&bidirectional_state.ck, &[0; 0]);
 344                                                 ck = bidirectional_state.ck.clone();
 345                                                 res
 346                                         },
 347                                         _ => panic!("Wrong direction for act"),
 348                                 },
 349                         _ => panic!("Cannot get act one after noise handshake completes"),
 350                 };
 351
 352                 let (sk, rk) = final_hkdf;
 353                 self.noise_state = NoiseState::Finished {
 354                         sk,
 355                         sn: 0,
 356                         sck: ck.clone(),
 357                         rk,
 358                         rn: 0,
 359                         rck: ck,
 360                 };
 361
 362                 Ok((res, self.their_node_id.unwrap().clone()))
 363         }
 364
 365         pub fn process_act_three(&mut self, act_three: &[u8]) -> Result<PublicKey, LightningError> {
 366                 assert_eq!(act_three.len(), 66);
 367
 368                 let final_hkdf;
 369                 let ck;
 370                 match self.noise_state {
 371                         NoiseState::InProgress { ref state, ref directional_state, ref mut bidirectional_state } =>
 372                                 match directional_state {
 373                                         &DirectionalNoiseState::Inbound { ie: _, ref re, ref temp_k2 } => {
 374                                                 if *state != NoiseStep::PostActTwo {
 375                                                         panic!("Requested act at wrong step");
 376                                                 }
 377                                                 if act_three[0] != 0 {
 378                                                         return Err(LightningError{err: format!("Unknown handshake version number {}", act_three[0]), action: msgs::ErrorAction::DisconnectPeer{ msg: None }});
 379                                                 }
 380
 381                                                 let mut their_node_id = [0; 33];
 382                                                 PeerChannelEncryptor::decrypt_with_ad(&mut their_node_id, 1, &temp_k2.unwrap(), &bidirectional_state.h, &act_three[1..50])?;
 383                                                 self.their_node_id = Some(match PublicKey::from_slice(&their_node_id) {
 384                                                         Ok(key) => key,
 385                                                         Err(_) => return Err(LightningError{err: format!("Bad node_id from peer, {}", &their_node_id.to_hex()), action: msgs::ErrorAction::DisconnectPeer{ msg: None }}),
 386                                                 });
 387
 388                                                 let mut sha = Sha256::engine();
 389                                                 sha.input(&bidirectional_state.h);
 390                                                 sha.input(&act_three[1..50]);
 391                                                 bidirectional_state.h = Sha256::from_engine(sha).into_inner();
 392
 393                                                 let ss = SharedSecret::new(&self.their_node_id.unwrap(), &re.unwrap());
 394                                                 let temp_k = PeerChannelEncryptor::hkdf(bidirectional_state, ss);
 395
 396                                                 PeerChannelEncryptor::decrypt_with_ad(&mut [0; 0], 0, &temp_k, &bidirectional_state.h, &act_three[50..])?;
 397                                                 final_hkdf = hkdf_extract_expand_twice(&bidirectional_state.ck, &[0; 0]);
 398                                                 ck = bidirectional_state.ck.clone();
 399                                         },
 400                                         _ => panic!("Wrong direction for act"),
 401                                 },
 402                         _ => panic!("Cannot get act one after noise handshake completes"),
 403                 }
 404
 405                 let (rk, sk) = final_hkdf;
 406                 self.noise_state = NoiseState::Finished {
 407                         sk,
 408                         sn: 0,
 409                         sck: ck.clone(),
 410                         rk,
 411                         rn: 0,
 412                         rck: ck,
 413                 };
 414
 415                 Ok(self.their_node_id.unwrap().clone())
 416         }
 417
 418         /// Encrypts the given pre-serialized message, returning the encrypted version.
 419         /// panics if msg.len() > 65535 or Noise handshake has not finished.
 420         pub fn encrypt_buffer(&mut self, msg: &[u8]) -> Vec<u8> {
 421                 if msg.len() > LN_MAX_MSG_LEN {
 422                         panic!("Attempted to encrypt message longer than 65535 bytes!");
 423                 }
 424
 425                 let mut res = Vec::with_capacity(msg.len() + 16*2 + 2);
 426                 res.resize(msg.len() + 16*2 + 2, 0);
 427
 428                 match self.noise_state {
 429                         NoiseState::Finished { ref mut sk, ref mut sn, ref mut sck, rk: _, rn: _, rck: _ } => {
 430                                 if *sn >= 1000 {
 431                                         let (new_sck, new_sk) = hkdf_extract_expand_twice(sck, sk);
 432                                         *sck = new_sck;
 433                                         *sk = new_sk;
 434                                         *sn = 0;
 435                                 }
 436
 437                                 Self::encrypt_with_ad(&mut res[0..16+2], *sn, sk, &[0; 0], &(msg.len() as u16).to_be_bytes());
 438                                 *sn += 1;
 439
 440                                 Self::encrypt_with_ad(&mut res[16+2..], *sn, sk, &[0; 0], msg);
 441                                 *sn += 1;
 442                         },
 443                         _ => panic!("Tried to encrypt a message prior to noise handshake completion"),
 444                 }
 445
 446                 res
 447         }
 448
 449         /// Encrypts the given message, returning the encrypted version.
 450         /// panics if the length of `message`, once encoded, is greater than 65535 or if the Noise
 451         /// handshake has not finished.
 452         pub fn encrypt_message<M: wire::Type>(&mut self, message: &M) -> Vec<u8> {
 453                 // Allocate a buffer with 2KB, fitting most common messages. Reserve the first 16+2 bytes
 454                 // for the 2-byte message type prefix and its MAC.
 455                 let mut res = VecWriter(Vec::with_capacity(MSG_BUF_ALLOC_SIZE));
 456                 res.0.resize(16 + 2, 0);
 457                 wire::write(message, &mut res).expect("In-memory messages must never fail to serialize");
 458
 459                 let msg_len = res.0.len() - 16 - 2;
 460                 if msg_len > LN_MAX_MSG_LEN {
 461                         panic!("Attempted to encrypt message longer than 65535 bytes!");
 462                 }
 463
 464                 match self.noise_state {
 465                         NoiseState::Finished { ref mut sk, ref mut sn, ref mut sck, rk: _, rn: _, rck: _ } => {
 466                                 if *sn >= 1000 {
 467                                         let (new_sck, new_sk) = hkdf_extract_expand_twice(sck, sk);
 468                                         *sck = new_sck;
 469                                         *sk = new_sk;
 470                                         *sn = 0;
 471                                 }
 472
 473                                 Self::encrypt_with_ad(&mut res.0[0..16+2], *sn, sk, &[0; 0], &(msg_len as u16).to_be_bytes());
 474                                 *sn += 1;
 475
 476                                 Self::encrypt_in_place_with_ad(&mut res.0, 16+2, *sn, sk, &[0; 0]);
 477                                 *sn += 1;
 478                         },
 479                         _ => panic!("Tried to encrypt a message prior to noise handshake completion"),
 480                 }
 481
 482                 res.0
 483         }
 484
 485         /// Decrypts a message length header from the remote peer.
 486         /// panics if noise handshake has not yet finished or msg.len() != 18
 487         pub fn decrypt_length_header(&mut self, msg: &[u8]) -> Result<u16, LightningError> {
 488                 assert_eq!(msg.len(), 16+2);
 489
 490                 match self.noise_state {
 491                         NoiseState::Finished { sk: _, sn: _, sck: _, ref mut rk, ref mut rn, ref mut rck } => {
 492                                 if *rn >= 1000 {
 493                                         let (new_rck, new_rk) = hkdf_extract_expand_twice(rck, rk);
 494                                         *rck = new_rck;
 495                                         *rk = new_rk;
 496                                         *rn = 0;
 497                                 }
 498
 499                                 let mut res = [0; 2];
 500                                 Self::decrypt_with_ad(&mut res, *rn, rk, &[0; 0], msg)?;
 501                                 *rn += 1;
 502                                 Ok(u16::from_be_bytes(res))
 503                         },
 504                         _ => panic!("Tried to decrypt a message prior to noise handshake completion"),
 505                 }
 506         }
 507
 508         /// Decrypts the given message.
 509         /// panics if msg.len() > 65535 + 16
 510         pub fn decrypt_message(&mut self, msg: &[u8]) -> Result<Vec<u8>, LightningError> {
 511                 if msg.len() > LN_MAX_MSG_LEN + 16 {
 512                         panic!("Attempted to decrypt message longer than 65535 + 16 bytes!");
 513                 }
 514
 515                 match self.noise_state {
 516                         NoiseState::Finished { sk: _, sn: _, sck: _, ref rk, ref mut rn, rck: _ } => {
 517                                 let mut res = Vec::with_capacity(msg.len() - 16);
 518                                 res.resize(msg.len() - 16, 0);
 519                                 Self::decrypt_with_ad(&mut res[..], *rn, rk, &[0; 0], msg)?;
 520                                 *rn += 1;
 521
 522                                 Ok(res)
 523                         },
 524                         _ => panic!("Tried to decrypt a message prior to noise handshake completion"),
 525                 }
 526         }
 527
 528         pub fn get_noise_step(&self) -> NextNoiseStep {
 529                 match self.noise_state {
 530                         NoiseState::InProgress {ref state, ..} => {
 531                                 match state {
 532                                         &NoiseStep::PreActOne => NextNoiseStep::ActOne,
 533                                         &NoiseStep::PostActOne => NextNoiseStep::ActTwo,
 534                                         &NoiseStep::PostActTwo => NextNoiseStep::ActThree,
 535                                 }
 536                         },
 537                         NoiseState::Finished {..} => NextNoiseStep::NoiseComplete,
 538                 }
 539         }
 540
 541         pub fn is_ready_for_encryption(&self) -> bool {
 542                 match self.noise_state {
 543                         NoiseState::InProgress {..} => { false },
 544                         NoiseState::Finished {..} => { true }
 545                 }
 546         }
 547 }
 548
 549 #[cfg(test)]
 550 mod tests {
 551         use super::LN_MAX_MSG_LEN;
 552
 553         use bitcoin::secp256k1::{PublicKey, SecretKey};
 554         use bitcoin::secp256k1::Secp256k1;
 555
 556         use hex;
 557
 558         use crate::ln::peer_channel_encryptor::{PeerChannelEncryptor,NoiseState};
 559         use crate::util::test_utils::TestNodeSigner;
 560
 561         fn get_outbound_peer_for_initiator_test_vectors() -> PeerChannelEncryptor {
 562                 let their_node_id = PublicKey::from_slice(&hex::decode("028d7500dd4c12685d1f568b4c2b5048e8534b873319f3a8daa612b469132ec7f7").unwrap()[..]).unwrap();
 563                 let secp_ctx = Secp256k1::signing_only();
 564
 565                 let mut outbound_peer = PeerChannelEncryptor::new_outbound(their_node_id, SecretKey::from_slice(&hex::decode("1212121212121212121212121212121212121212121212121212121212121212").unwrap()[..]).unwrap());
 566                 assert_eq!(outbound_peer.get_act_one(&secp_ctx)[..], hex::decode("00036360e856310ce5d294e8be33fc807077dc56ac80d95d9cd4ddbd21325eff73f70df6086551151f58b8afe6c195782c6a").unwrap()[..]);
 567                 outbound_peer
 568         }
 569
 570         fn get_inbound_peer_for_test_vectors() -> PeerChannelEncryptor {
 571                 // transport-responder successful handshake
 572                 let our_node_id = SecretKey::from_slice(&hex::decode("2121212121212121212121212121212121212121212121212121212121212121").unwrap()[..]).unwrap();
 573                 let our_ephemeral = SecretKey::from_slice(&hex::decode("2222222222222222222222222222222222222222222222222222222222222222").unwrap()[..]).unwrap();
 574                 let secp_ctx = Secp256k1::new();
 575                 let node_signer = TestNodeSigner::new(our_node_id);
 576
 577                 let mut inbound_peer = PeerChannelEncryptor::new_inbound(&&node_signer);
 578
 579                 let act_one = hex::decode("00036360e856310ce5d294e8be33fc807077dc56ac80d95d9cd4ddbd21325eff73f70df6086551151f58b8afe6c195782c6a").unwrap().to_vec();
 580                 assert_eq!(inbound_peer.process_act_one_with_keys(&act_one[..], &&node_signer, our_ephemeral.clone(), &secp_ctx).unwrap()[..], hex::decode("0002466d7fcae563e5cb09a0d1870bb580344804617879a14949cf22285f1bae3f276e2470b93aac583c9ef6eafca3f730ae").unwrap()[..]);
 581
 582                 let act_three = hex::decode("00b9e3a702e93e3a9948c2ed6e5fd7590a6e1c3a0344cfc9d5b57357049aa22355361aa02e55a8fc28fef5bd6d71ad0c38228dc68b1c466263b47fdf31e560e139ba").unwrap().to_vec();
 583                 // test vector doesn't specify the initiator static key, but it's the same as the one
 584                 // from transport-initiator successful handshake
 585                 assert_eq!(inbound_peer.process_act_three(&act_three[..]).unwrap().serialize()[..], hex::decode("034f355bdcb7cc0af728ef3cceb9615d90684bb5b2ca5f859ab0f0b704075871aa").unwrap()[..]);
 586
 587                 match inbound_peer.noise_state {
 588                         NoiseState::Finished { sk, sn, sck, rk, rn, rck } => {
 589                                 assert_eq!(sk, hex::decode("bb9020b8965f4df047e07f955f3c4b88418984aadc5cdb35096b9ea8fa5c3442").unwrap()[..]);
 590                                 assert_eq!(sn, 0);
 591                                 assert_eq!(sck, hex::decode("919219dbb2920afa8db80f9a51787a840bcf111ed8d588caf9ab4be716e42b01").unwrap()[..]);
 592                                 assert_eq!(rk, hex::decode("969ab31b4d288cedf6218839b27a3e2140827047f2c0f01bf5c04435d43511a9").unwrap()[..]);
 593                                 assert_eq!(rn, 0);
 594                                 assert_eq!(rck, hex::decode("919219dbb2920afa8db80f9a51787a840bcf111ed8d588caf9ab4be716e42b01").unwrap()[..]);
 595                         },
 596                         _ => panic!()
 597                 }
 598
 599                 inbound_peer
 600         }
 601
 602         #[test]
 603         fn noise_initiator_test_vectors() {
 604                 let our_node_id = SecretKey::from_slice(&hex::decode("1111111111111111111111111111111111111111111111111111111111111111").unwrap()[..]).unwrap();
 605                 let node_signer = TestNodeSigner::new(our_node_id);
 606
 607                 {
 608                         // transport-initiator successful handshake
 609                         let mut outbound_peer = get_outbound_peer_for_initiator_test_vectors();
 610
 611                         let act_two = hex::decode("0002466d7fcae563e5cb09a0d1870bb580344804617879a14949cf22285f1bae3f276e2470b93aac583c9ef6eafca3f730ae").unwrap().to_vec();
 612                         assert_eq!(outbound_peer.process_act_two(&act_two[..], &&node_signer).unwrap().0[..], hex::decode("00b9e3a702e93e3a9948c2ed6e5fd7590a6e1c3a0344cfc9d5b57357049aa22355361aa02e55a8fc28fef5bd6d71ad0c38228dc68b1c466263b47fdf31e560e139ba").unwrap()[..]);
 613
 614                         match outbound_peer.noise_state {
 615                                 NoiseState::Finished { sk, sn, sck, rk, rn, rck } => {
 616                                         assert_eq!(sk, hex::decode("969ab31b4d288cedf6218839b27a3e2140827047f2c0f01bf5c04435d43511a9").unwrap()[..]);
 617                                         assert_eq!(sn, 0);
 618                                         assert_eq!(sck, hex::decode("919219dbb2920afa8db80f9a51787a840bcf111ed8d588caf9ab4be716e42b01").unwrap()[..]);
 619                                         assert_eq!(rk, hex::decode("bb9020b8965f4df047e07f955f3c4b88418984aadc5cdb35096b9ea8fa5c3442").unwrap()[..]);
 620                                         assert_eq!(rn, 0);
 621                                         assert_eq!(rck, hex::decode("919219dbb2920afa8db80f9a51787a840bcf111ed8d588caf9ab4be716e42b01").unwrap()[..]);
 622                                 },
 623                                 _ => panic!()
 624                         }
 625                 }
 626                 {
 627                         // transport-initiator act2 short read test
 628                         // Can't actually test this cause process_act_two requires you pass the right length!
 629                 }
 630                 {
 631                         // transport-initiator act2 bad version test
 632                         let mut outbound_peer = get_outbound_peer_for_initiator_test_vectors();
 633
 634                         let act_two = hex::decode("0102466d7fcae563e5cb09a0d1870bb580344804617879a14949cf22285f1bae3f276e2470b93aac583c9ef6eafca3f730ae").unwrap().to_vec();
 635                         assert!(outbound_peer.process_act_two(&act_two[..], &&node_signer).is_err());
 636                 }
 637
 638                 {
 639                         // transport-initiator act2 bad key serialization test
 640                         let mut outbound_peer = get_outbound_peer_for_initiator_test_vectors();
 641
 642                         let act_two = hex::decode("0004466d7fcae563e5cb09a0d1870bb580344804617879a14949cf22285f1bae3f276e2470b93aac583c9ef6eafca3f730ae").unwrap().to_vec();
 643                         assert!(outbound_peer.process_act_two(&act_two[..], &&node_signer).is_err());
 644                 }
 645
 646                 {
 647                         // transport-initiator act2 bad MAC test
 648                         let mut outbound_peer = get_outbound_peer_for_initiator_test_vectors();
 649
 650                         let act_two = hex::decode("0002466d7fcae563e5cb09a0d1870bb580344804617879a14949cf22285f1bae3f276e2470b93aac583c9ef6eafca3f730af").unwrap().to_vec();
 651                         assert!(outbound_peer.process_act_two(&act_two[..], &&node_signer).is_err());
 652                 }
 653         }
 654
 655         #[test]
 656         fn noise_responder_test_vectors() {
 657                 let our_node_id = SecretKey::from_slice(&hex::decode("2121212121212121212121212121212121212121212121212121212121212121").unwrap()[..]).unwrap();
 658                 let our_ephemeral = SecretKey::from_slice(&hex::decode("2222222222222222222222222222222222222222222222222222222222222222").unwrap()[..]).unwrap();
 659                 let secp_ctx = Secp256k1::new();
 660                 let node_signer = TestNodeSigner::new(our_node_id);
 661
 662                 {
 663                         let _ = get_inbound_peer_for_test_vectors();
 664                 }
 665                 {
 666                         // transport-responder act1 short read test
 667                         // Can't actually test this cause process_act_one requires you pass the right length!
 668                 }
 669                 {
 670                         // transport-responder act1 bad version test
 671                         let mut inbound_peer = PeerChannelEncryptor::new_inbound(&&node_signer);
 672
 673                         let act_one = hex::decode("01036360e856310ce5d294e8be33fc807077dc56ac80d95d9cd4ddbd21325eff73f70df6086551151f58b8afe6c195782c6a").unwrap().to_vec();
 674                         assert!(inbound_peer.process_act_one_with_keys(&act_one[..], &&node_signer, our_ephemeral.clone(), &secp_ctx).is_err());
 675                 }
 676                 {
 677                         // transport-responder act1 bad key serialization test
 678                         let mut inbound_peer = PeerChannelEncryptor::new_inbound(&&node_signer);
 679
 680                         let act_one =hex::decode("00046360e856310ce5d294e8be33fc807077dc56ac80d95d9cd4ddbd21325eff73f70df6086551151f58b8afe6c195782c6a").unwrap().to_vec();
 681                         assert!(inbound_peer.process_act_one_with_keys(&act_one[..], &&node_signer, our_ephemeral.clone(), &secp_ctx).is_err());
 682                 }
 683                 {
 684                         // transport-responder act1 bad MAC test
 685                         let mut inbound_peer = PeerChannelEncryptor::new_inbound(&&node_signer);
 686
 687                         let act_one = hex::decode("00036360e856310ce5d294e8be33fc807077dc56ac80d95d9cd4ddbd21325eff73f70df6086551151f58b8afe6c195782c6b").unwrap().to_vec();
 688                         assert!(inbound_peer.process_act_one_with_keys(&act_one[..], &&node_signer, our_ephemeral.clone(), &secp_ctx).is_err());
 689                 }
 690                 {
 691                         // transport-responder act3 bad version test
 692                         let mut inbound_peer = PeerChannelEncryptor::new_inbound(&&node_signer);
 693
 694                         let act_one = hex::decode("00036360e856310ce5d294e8be33fc807077dc56ac80d95d9cd4ddbd21325eff73f70df6086551151f58b8afe6c195782c6a").unwrap().to_vec();
 695                         assert_eq!(inbound_peer.process_act_one_with_keys(&act_one[..], &&node_signer, our_ephemeral.clone(), &secp_ctx).unwrap()[..], hex::decode("0002466d7fcae563e5cb09a0d1870bb580344804617879a14949cf22285f1bae3f276e2470b93aac583c9ef6eafca3f730ae").unwrap()[..]);
 696
 697                         let act_three = hex::decode("01b9e3a702e93e3a9948c2ed6e5fd7590a6e1c3a0344cfc9d5b57357049aa22355361aa02e55a8fc28fef5bd6d71ad0c38228dc68b1c466263b47fdf31e560e139ba").unwrap().to_vec();
 698                         assert!(inbound_peer.process_act_three(&act_three[..]).is_err());
 699                 }
 700                 {
 701                         // transport-responder act3 short read test
 702                         // Can't actually test this cause process_act_three requires you pass the right length!
 703                 }
 704                 {
 705                         // transport-responder act3 bad MAC for ciphertext test
 706                         let mut inbound_peer = PeerChannelEncryptor::new_inbound(&&node_signer);
 707
 708                         let act_one = hex::decode("00036360e856310ce5d294e8be33fc807077dc56ac80d95d9cd4ddbd21325eff73f70df6086551151f58b8afe6c195782c6a").unwrap().to_vec();
 709                         assert_eq!(inbound_peer.process_act_one_with_keys(&act_one[..], &&node_signer, our_ephemeral.clone(), &secp_ctx).unwrap()[..], hex::decode("0002466d7fcae563e5cb09a0d1870bb580344804617879a14949cf22285f1bae3f276e2470b93aac583c9ef6eafca3f730ae").unwrap()[..]);
 710
 711                         let act_three = hex::decode("00c9e3a702e93e3a9948c2ed6e5fd7590a6e1c3a0344cfc9d5b57357049aa22355361aa02e55a8fc28fef5bd6d71ad0c38228dc68b1c466263b47fdf31e560e139ba").unwrap().to_vec();
 712                         assert!(inbound_peer.process_act_three(&act_three[..]).is_err());
 713                 }
 714                 {
 715                         // transport-responder act3 bad rs test
 716                         let mut inbound_peer = PeerChannelEncryptor::new_inbound(&&node_signer);
 717
 718                         let act_one = hex::decode("00036360e856310ce5d294e8be33fc807077dc56ac80d95d9cd4ddbd21325eff73f70df6086551151f58b8afe6c195782c6a").unwrap().to_vec();
 719                         assert_eq!(inbound_peer.process_act_one_with_keys(&act_one[..], &&node_signer, our_ephemeral.clone(), &secp_ctx).unwrap()[..], hex::decode("0002466d7fcae563e5cb09a0d1870bb580344804617879a14949cf22285f1bae3f276e2470b93aac583c9ef6eafca3f730ae").unwrap()[..]);
 720
 721                         let act_three = hex::decode("00bfe3a702e93e3a9948c2ed6e5fd7590a6e1c3a0344cfc9d5b57357049aa2235536ad09a8ee351870c2bb7f78b754a26c6cef79a98d25139c856d7efd252c2ae73c").unwrap().to_vec();
 722                         assert!(inbound_peer.process_act_three(&act_three[..]).is_err());
 723                 }
 724                 {
 725                         // transport-responder act3 bad MAC test
 726                         let mut inbound_peer = PeerChannelEncryptor::new_inbound(&&node_signer);
 727
 728                         let act_one = hex::decode("00036360e856310ce5d294e8be33fc807077dc56ac80d95d9cd4ddbd21325eff73f70df6086551151f58b8afe6c195782c6a").unwrap().to_vec();
 729                         assert_eq!(inbound_peer.process_act_one_with_keys(&act_one[..], &&node_signer, our_ephemeral.clone(), &secp_ctx).unwrap()[..], hex::decode("0002466d7fcae563e5cb09a0d1870bb580344804617879a14949cf22285f1bae3f276e2470b93aac583c9ef6eafca3f730ae").unwrap()[..]);
 730
 731                         let act_three = hex::decode("00b9e3a702e93e3a9948c2ed6e5fd7590a6e1c3a0344cfc9d5b57357049aa22355361aa02e55a8fc28fef5bd6d71ad0c38228dc68b1c466263b47fdf31e560e139bb").unwrap().to_vec();
 732                         assert!(inbound_peer.process_act_three(&act_three[..]).is_err());
 733                 }
 734         }
 735
 736
 737         #[test]
 738         fn message_encryption_decryption_test_vectors() {
 739                 // We use the same keys as the initiator and responder test vectors, so we copy those tests
 740                 // here and use them to encrypt.
 741                 let mut outbound_peer = get_outbound_peer_for_initiator_test_vectors();
 742
 743                 {
 744                         let our_node_id = SecretKey::from_slice(&hex::decode("1111111111111111111111111111111111111111111111111111111111111111").unwrap()[..]).unwrap();
 745                         let node_signer = TestNodeSigner::new(our_node_id);
 746
 747                         let act_two = hex::decode("0002466d7fcae563e5cb09a0d1870bb580344804617879a14949cf22285f1bae3f276e2470b93aac583c9ef6eafca3f730ae").unwrap().to_vec();
 748                         assert_eq!(outbound_peer.process_act_two(&act_two[..], &&node_signer).unwrap().0[..], hex::decode("00b9e3a702e93e3a9948c2ed6e5fd7590a6e1c3a0344cfc9d5b57357049aa22355361aa02e55a8fc28fef5bd6d71ad0c38228dc68b1c466263b47fdf31e560e139ba").unwrap()[..]);
 749
 750                         match outbound_peer.noise_state {
 751                                 NoiseState::Finished { sk, sn, sck, rk, rn, rck } => {
 752                                         assert_eq!(sk, hex::decode("969ab31b4d288cedf6218839b27a3e2140827047f2c0f01bf5c04435d43511a9").unwrap()[..]);
 753                                         assert_eq!(sn, 0);
 754                                         assert_eq!(sck, hex::decode("919219dbb2920afa8db80f9a51787a840bcf111ed8d588caf9ab4be716e42b01").unwrap()[..]);
 755                                         assert_eq!(rk, hex::decode("bb9020b8965f4df047e07f955f3c4b88418984aadc5cdb35096b9ea8fa5c3442").unwrap()[..]);
 756                                         assert_eq!(rn, 0);
 757                                         assert_eq!(rck, hex::decode("919219dbb2920afa8db80f9a51787a840bcf111ed8d588caf9ab4be716e42b01").unwrap()[..]);
 758                                 },
 759                                 _ => panic!()
 760                         }
 761                 }
 762
 763                 let mut inbound_peer = get_inbound_peer_for_test_vectors();
 764
 765                 for i in 0..1005 {
 766                         let msg = [0x68, 0x65, 0x6c, 0x6c, 0x6f];
 767                         let res = outbound_peer.encrypt_buffer(&msg);
 768                         assert_eq!(res.len(), 5 + 2*16 + 2);
 769
 770                         let len_header = res[0..2+16].to_vec();
 771                         assert_eq!(inbound_peer.decrypt_length_header(&len_header[..]).unwrap() as usize, msg.len());
 772                         assert_eq!(inbound_peer.decrypt_message(&res[2+16..]).unwrap()[..], msg[..]);
 773
 774                         if i == 0 {
 775                                 assert_eq!(res, hex::decode("cf2b30ddf0cf3f80e7c35a6e6730b59fe802473180f396d88a8fb0db8cbcf25d2f214cf9ea1d95").unwrap());
 776                         } else if i == 1 {
 777                                 assert_eq!(res, hex::decode("72887022101f0b6753e0c7de21657d35a4cb2a1f5cde2650528bbc8f837d0f0d7ad833b1a256a1").unwrap());
 778                         } else if i == 500 {
 779                                 assert_eq!(res, hex::decode("178cb9d7387190fa34db9c2d50027d21793c9bc2d40b1e14dcf30ebeeeb220f48364f7a4c68bf8").unwrap());
 780                         } else if i == 501 {
 781                                 assert_eq!(res, hex::decode("1b186c57d44eb6de4c057c49940d79bb838a145cb528d6e8fd26dbe50a60ca2c104b56b60e45bd").unwrap());
 782                         } else if i == 1000 {
 783                                 assert_eq!(res, hex::decode("4a2f3cc3b5e78ddb83dcb426d9863d9d9a723b0337c89dd0b005d89f8d3c05c52b76b29b740f09").unwrap());
 784                         } else if i == 1001 {
 785                                 assert_eq!(res, hex::decode("2ecd8c8a5629d0d02ab457a0fdd0f7b90a192cd46be5ecb6ca570bfc5e268338b1a16cf4ef2d36").unwrap());
 786                         }
 787                 }
 788         }
 789
 790         #[test]
 791         fn max_msg_len_limit_value() {
 792                 assert_eq!(LN_MAX_MSG_LEN, 65535);
 793                 assert_eq!(LN_MAX_MSG_LEN, ::core::u16::MAX as usize);
 794         }
 795
 796         #[test]
 797         #[should_panic(expected = "Attempted to encrypt message longer than 65535 bytes!")]
 798         fn max_message_len_encryption() {
 799                 let mut outbound_peer = get_outbound_peer_for_initiator_test_vectors();
 800                 let msg = [4u8; LN_MAX_MSG_LEN + 1];
 801                 outbound_peer.encrypt_buffer(&msg);
 802         }
 803
 804         #[test]
 805         #[should_panic(expected = "Attempted to decrypt message longer than 65535 + 16 bytes!")]
 806         fn max_message_len_decryption() {
 807                 let mut inbound_peer = get_inbound_peer_for_test_vectors();
 808
 809                 // MSG should not exceed LN_MAX_MSG_LEN + 16
 810                 let msg = [4u8; LN_MAX_MSG_LEN + 17];
 811                 inbound_peer.decrypt_message(&msg).unwrap();
 812         }
 813 }