Move parser code to zerocopy

5 files changed, 138 insertions, 151 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 0b4d902..1ff70c1 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -124,6 +124,22 @@ version = "0.2.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
+name = "proc-macro2"
+version = "0.4.30"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "unicode-xid 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "quote"
+version = "0.6.13"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "proc-macro2 0.4.30 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
 name = "rand"
 version = "0.3.23"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -286,6 +302,27 @@ version = "2.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
+name = "syn"
+version = "0.15.42"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "proc-macro2 0.4.30 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 0.6.13 (registry+https://github.com/rust-lang/crates.io-index)",
+ "unicode-xid 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "synstructure"
+version = "0.10.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "proc-macro2 0.4.30 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quote 0.6.13 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.42 (registry+https://github.com/rust-lang/crates.io-index)",
+ "unicode-xid 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
 name = "time"
 version = "0.1.42"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -301,10 +338,16 @@ version = "1.10.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
+name = "unicode-xid"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
 name = "wg-handshake"
 version = "0.1.0"
 dependencies = [
  "blake2 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "byteorder 1.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "generic-array 0.12.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "hex 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "hmac 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -312,6 +355,7 @@ dependencies = [
  "rust-crypto 0.2.36 (registry+https://github.com/rust-lang/crates.io-index)",
  "spin 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "x25519-dalek 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "zerocopy 0.2.7 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -343,6 +387,25 @@ dependencies = [
  "rand_core 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "zerocopy"
+version = "0.2.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "byteorder 1.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "zerocopy-derive 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "zerocopy-derive"
+version = "0.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "proc-macro2 0.4.30 (registry+https://github.com/rust-lang/crates.io-index)",
+ "syn 0.15.42 (registry+https://github.com/rust-lang/crates.io-index)",
+ "synstructure 0.10.2 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [metadata]
 "checksum autocfg 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)" = "0e49efa51329a5fd37e7c79db4621af617cd4e3e5bc224939808d076077077bf"
 "checksum bitflags 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "3d155346769a6855b86399e9bc3814ab343cd3d62c7e985113d46a0ec3c281fd"
@@ -362,6 +425,8 @@ dependencies = [
 "checksum hmac 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)" = "5dcb5e64cda4c23119ab41ba960d1e170a774c8e4b9d9e6a9bc18aabf5e59695"
 "checksum libc 0.2.59 (registry+https://github.com/rust-lang/crates.io-index)" = "3262021842bf00fe07dbd6cf34ff25c99d7a7ebef8deea84db72be3ea3bb0aff"
 "checksum opaque-debug 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "93f5bb2e8e8dec81642920ccff6b61f1eb94fa3020c5a325c9851ff604152409"
+"checksum proc-macro2 0.4.30 (registry+https://github.com/rust-lang/crates.io-index)" = "cf3d2011ab5c909338f7887f4fc896d35932e29146c12c8d01da6b22a80ba759"
+"checksum quote 0.6.13 (registry+https://github.com/rust-lang/crates.io-index)" = "6ce23b6b870e8f94f81fb0a363d65d86675884b34a09043c81e5562f11c1f8e1"
 "checksum rand 0.3.23 (registry+https://github.com/rust-lang/crates.io-index)" = "64ac302d8f83c0c1974bf758f6b041c6c8ada916fbb44a609158ca8b064cc76c"
 "checksum rand 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)" = "552840b97013b1a26992c11eac34bdd778e464601a4c2054b5f0bff7c6761293"
 "checksum rand 0.6.5 (registry+https://github.com/rust-lang/crates.io-index)" = "6d71dacdc3c88c1fde3885a3be3fbab9f35724e6ce99467f7d9c5026132184ca"
@@ -381,9 +446,14 @@ dependencies = [
 "checksum spin 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)" = "44363f6f51401c34e7be73db0db371c04705d35efbe9f7d6082e03a921a32c55"
 "checksum subtle 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "2d67a5a62ba6e01cb2192ff309324cb4875d0c451d55fe2319433abe7a05a8ee"
 "checksum subtle 2.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "702662512f3ddeb74a64ce2fbbf3707ee1b6bb663d28bb054e0779bbc720d926"
+"checksum syn 0.15.42 (registry+https://github.com/rust-lang/crates.io-index)" = "eadc09306ca51a40555dd6fc2b415538e9e18bc9f870e47b1a524a79fe2dcf5e"
+"checksum synstructure 0.10.2 (registry+https://github.com/rust-lang/crates.io-index)" = "02353edf96d6e4dc81aea2d8490a7e9db177bf8acb0e951c24940bf866cb313f"
 "checksum time 0.1.42 (registry+https://github.com/rust-lang/crates.io-index)" = "db8dcfca086c1143c9270ac42a2bbd8a7ee477b78ac8e45b19abfb0cbede4b6f"
 "checksum typenum 1.10.0 (registry+https://github.com/rust-lang/crates.io-index)" = "612d636f949607bdf9b123b4a6f6d966dedf3ff669f7f045890d3a4a73948169"
+"checksum unicode-xid 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "fc72304796d0818e357ead4e000d19c9c174ab23dc11093ac919054d20a6a7fc"
 "checksum winapi 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)" = "f10e386af2b13e47c89e7236a7a14a086791a2b88ebad6df9bf42040195cf770"
 "checksum winapi-i686-pc-windows-gnu 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"
 "checksum winapi-x86_64-pc-windows-gnu 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
 "checksum x25519-dalek 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)" = "4aca1ba6bec2719576bd20dfe5b24d9359552e616d10bff257e50cd85f745d17"
+"checksum zerocopy 0.2.7 (registry+https://github.com/rust-lang/crates.io-index)" = "56ae60eda58b25c5c4f5398e2144f72dc1881e50142e232b64e1ba8664d1ce38"
+"checksum zerocopy-derive 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)" = "746f425452bf1e4b74c78d594d5c6f51f8c978e57ba5c236a04ba1aecfc384a7"
diff --git a/Cargo.toml b/Cargo.toml
index 2ccb719..af24051 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -3,7 +3,7 @@ name = "wg-handshake"
 version = "0.1.0"
 authors = ["Mathias Hall-Andersen <mathias@hall-andersen.dk>"]
 edition = "2018"
-license = "GPL-3.0"
+license = "MIT"
 
 [dependencies]
 hex = "0.3"
@@ -13,6 +13,8 @@ blake2 = "0.8.0"
 hmac = "0.7.1"
 rust-crypto = "^0.2"
 generic-array = "0.12.3"
+zerocopy = "0.2.7"
+byteorder = "1.3.1"
 
 [dependencies.x25519-dalek]
 version = "^0.5"
diff --git a/src/device.rs b/src/device.rs
index 838ae63..93ea2aa 100644
--- a/src/device.rs
+++ b/src/device.rs
@@ -202,7 +202,6 @@ mod tests {
     use super::*;
     use hex;
     use messages::*;
-    use std::convert::TryFrom;
 
     #[test]
     fn handshake() {
@@ -234,7 +233,7 @@ mod tests {
             let msg1 = dev1.begin(&pk2).unwrap();
 
             println!("msg1 = {}", hex::encode(&msg1[..]));
-            println!("msg1 = {:?}", Initiation::try_from(&msg1[..]).unwrap());
+            println!("msg1 = {:?}", Initiation::parse(&msg1[..]).unwrap());
 
             // process initiation and create response
 
@@ -244,7 +243,7 @@ mod tests {
             let msg2 = msg2.unwrap();
 
             println!("msg2 = {}", hex::encode(&msg2[..]));
-            println!("msg2 = {:?}", Response::try_from(&msg2[..]).unwrap());
+            println!("msg2 = {:?}", Response::parse(&msg2[..]).unwrap());
 
             assert!(!ks_r.confirmed, "Responders key-pair is confirmed");
 
diff --git a/src/messages.rs b/src/messages.rs
index 136c899..04f1532 100644
--- a/src/messages.rs
+++ b/src/messages.rs
@@ -1,8 +1,11 @@
-use crate::types::*;
 use hex;
-use std::convert::TryFrom;
 use std::fmt;
-use std::mem;
+
+use byteorder::LittleEndian;
+use zerocopy::byteorder::U32;
+use zerocopy::{AsBytes, ByteSlice, FromBytes, LayoutVerified};
+
+use crate::types::*;
 
 const SIZE_TAG: usize = 16;
 const SIZE_X25519_POINT: usize = 32;
@@ -11,17 +14,11 @@ const SIZE_TIMESTAMP: usize = 12;
 pub const TYPE_INITIATION: u8 = 1;
 pub const TYPE_RESPONSE: u8 = 2;
 
-/* Functions related to the packing / unpacking of
- * the fixed-sized noise handshake messages.
- *
- * The unpacked types are unexposed implementation details.
- */
-
 #[repr(C)]
-#[derive(Copy, Clone)]
+#[derive(Copy, Clone, FromBytes, AsBytes)]
 pub struct Initiation {
-    f_type: u32,
-    pub f_sender: u32,
+    f_type: U32<LittleEndian>,
+    pub f_sender: U32<LittleEndian>,
     pub f_ephemeral: [u8; SIZE_X25519_POINT],
     pub f_static: [u8; SIZE_X25519_POINT],
     pub f_static_tag: [u8; SIZE_TAG],
@@ -29,63 +26,11 @@ pub struct Initiation {
     pub f_timestamp_tag: [u8; SIZE_TAG],
 }
 
-impl TryFrom<&[u8]> for Initiation {
-    type Error = HandshakeError;
-
-    fn try_from(value: &[u8]) -> Result<Self, Self::Error> {
-        // check length of slice matches message
-
-        if value.len() != mem::size_of::<Self>() {
-            return Err(HandshakeError::InvalidMessageFormat);
-        }
-
-        // create owned copy
-
-        let mut owned = [0u8; mem::size_of::<Self>()];
-        let mut msg: Self;
-        owned.copy_from_slice(value);
-
-        // cast to Initiation
-
-        unsafe {
-            msg = mem::transmute::<[u8; mem::size_of::<Self>()], Self>(owned);
-        };
-
-        // correct endianness
-
-        msg.f_type = msg.f_type.to_le();
-        msg.f_sender = msg.f_sender.to_le();
-
-        // check type and reserved fields
-
-        if msg.f_type != (TYPE_INITIATION as u32) {
-            return Err(HandshakeError::InvalidMessageFormat);
-        }
-
-        Ok(msg)
-    }
-}
-
-impl Into<Vec<u8>> for Initiation {
-    fn into(self) -> Vec<u8> {
-        // correct endianness
-        let mut msg = self;
-        msg.f_type = msg.f_type.to_le();
-        msg.f_sender = msg.f_sender.to_le();
-
-        // cast to array
-        let array: [u8; mem::size_of::<Self>()];
-        unsafe { array = mem::transmute::<Self, [u8; mem::size_of::<Self>()]>(msg) };
-
-        array.to_vec()
-    }
-}
-
 impl Default for Initiation {
     fn default() -> Self {
         Self {
-            f_type: TYPE_INITIATION as u32,
-            f_sender: 0,
+            f_type: <U32<LittleEndian>>::new(TYPE_INITIATION as u32),
+            f_sender: <U32<LittleEndian>>::new(0),
             f_ephemeral: [0u8; SIZE_X25519_POINT],
             f_static: [0u8; SIZE_X25519_POINT],
             f_static_tag: [0u8; SIZE_TAG],
@@ -95,12 +40,25 @@ impl Default for Initiation {
     }
 }
 
+impl Initiation {
+    pub fn parse<B : ByteSlice>(bytes: B) -> Result<LayoutVerified<B, Self>, HandshakeError> {
+        let msg: LayoutVerified<B, Self> =
+            LayoutVerified::new(bytes).ok_or(HandshakeError::InvalidMessageFormat)?;
+
+        if msg.f_type.get() != (TYPE_INITIATION as u32) {
+            return Err(HandshakeError::InvalidMessageFormat);
+        }
+
+        Ok(msg)
+    }
+}
+
 impl fmt::Debug for Initiation {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f,
             "MessageInitiation {{ type = {}, sender = {}, ephemeral = {}, static = {}|{}, timestamp = {}|{} }}",
-            self.f_type,
-            self.f_sender,
+            self.f_type.get(),
+            self.f_sender.get(),
             hex::encode(self.f_ephemeral),
             hex::encode(self.f_static),
             hex::encode(self.f_static_tag),
@@ -113,8 +71,8 @@ impl fmt::Debug for Initiation {
 #[cfg(test)]
 impl PartialEq for Initiation {
     fn eq(&self, other: &Self) -> bool {
-        self.f_type == other.f_type
-            && self.f_sender == other.f_sender
+        self.f_type.get() == other.f_type.get()
+            && self.f_sender.get() == other.f_sender.get()
             && self.f_ephemeral[..] == other.f_ephemeral[..]
             && self.f_static[..] == other.f_static[..]
             && self.f_static_tag[..] == other.f_static_tag[..]
@@ -127,46 +85,21 @@ impl PartialEq for Initiation {
 impl Eq for Initiation {}
 
 #[repr(C)]
-#[derive(Copy, Clone)]
+#[derive(Copy, Clone, FromBytes, AsBytes)]
 pub struct Response {
-    f_type: u32,
-    pub f_sender: u32,
-    pub f_receiver: u32,
+    f_type: U32<LittleEndian>,
+    pub f_sender: U32<LittleEndian>,
+    pub f_receiver: U32<LittleEndian>,
     pub f_ephemeral: [u8; SIZE_X25519_POINT],
     pub f_empty_tag: [u8; SIZE_TAG],
 }
 
-impl TryFrom<&[u8]> for Response {
-    type Error = HandshakeError;
-
-    fn try_from(value: &[u8]) -> Result<Self, Self::Error> {
-        // check length of slice matches message
-
-        if value.len() != mem::size_of::<Self>() {
-            return Err(HandshakeError::InvalidMessageFormat);
-        }
-
-        // create owned copy
-
-        let mut owned = [0u8; mem::size_of::<Self>()];
-        let mut msg: Self;
-        owned.copy_from_slice(value);
-
-        // cast to MessageResponse
-
-        unsafe {
-            msg = mem::transmute::<[u8; mem::size_of::<Self>()], Self>(owned);
-        };
-
-        // correct endianness
+impl Response {
+    pub fn parse<B : ByteSlice>(bytes: B) -> Result<LayoutVerified<B, Self>, HandshakeError> {
+        let msg: LayoutVerified<B, Self> =
+            LayoutVerified::new(bytes).ok_or(HandshakeError::InvalidMessageFormat)?;
 
-        msg.f_type = msg.f_type.to_le();
-        msg.f_sender = msg.f_sender.to_le();
-        msg.f_receiver = msg.f_receiver.to_le();
-
-        // check type and reserved fields
-
-        if msg.f_type != (TYPE_RESPONSE as u32) {
+        if msg.f_type.get() != (TYPE_RESPONSE as u32) {
             return Err(HandshakeError::InvalidMessageFormat);
         }
 
@@ -174,28 +107,12 @@ impl TryFrom<&[u8]> for Response {
     }
 }
 
-impl Into<Vec<u8>> for Response {
-    fn into(self) -> Vec<u8> {
-        // correct endianness
-        let mut msg = self;
-        msg.f_type = msg.f_type.to_le();
-        msg.f_sender = msg.f_sender.to_le();
-        msg.f_receiver = msg.f_receiver.to_le();
-
-        // cast to array
-        let array: [u8; mem::size_of::<Self>()];
-        unsafe { array = mem::transmute::<Self, [u8; mem::size_of::<Self>()]>(msg) };
-
-        array.to_vec()
-    }
-}
-
 impl Default for Response {
     fn default() -> Self {
         Self {
-            f_type: TYPE_RESPONSE as u32,
-            f_sender: 0,
-            f_receiver: 0,
+            f_type: <U32<LittleEndian>>::new(TYPE_RESPONSE as u32),
+            f_sender: <U32<LittleEndian>>::ZERO,
+            f_receiver: <U32<LittleEndian>>::ZERO,
             f_ephemeral: [0u8; SIZE_X25519_POINT],
             f_empty_tag: [0u8; SIZE_TAG],
         }
@@ -234,8 +151,8 @@ mod tests {
     fn message_response_identity() {
         let mut msg: Response = Default::default();
 
-        msg.f_sender = 146252;
-        msg.f_receiver = 554442;
+        msg.f_sender.set(146252);
+        msg.f_receiver.set(554442);
         msg.f_ephemeral = [
             0xc1, 0x66, 0x0a, 0x0c, 0xdc, 0x0f, 0x6c, 0x51, 0x0f, 0xc2, 0xcc, 0x51, 0x52, 0x0c,
             0xde, 0x1e, 0xf7, 0xf1, 0xca, 0x90, 0x86, 0x72, 0xad, 0x67, 0xea, 0x89, 0x45, 0x44,
@@ -246,16 +163,16 @@ mod tests {
             0x2f, 0xde,
         ];
 
-        let buf: Vec<u8> = msg.into();
-        let msg_p: Response = Response::try_from(&buf[..]).unwrap();
-        assert_eq!(msg, msg_p);
+        let buf: Vec<u8> = msg.as_bytes().to_vec();
+        let msg_p = Response::parse(&buf[..]).unwrap();
+        assert_eq!(msg, *msg_p.into_ref());
     }
 
     #[test]
     fn message_initiate_identity() {
         let mut msg: Initiation = Default::default();
 
-        msg.f_sender = 575757;
+        msg.f_sender.set(575757);
         msg.f_ephemeral = [
             0xc1, 0x66, 0x0a, 0x0c, 0xdc, 0x0f, 0x6c, 0x51, 0x0f, 0xc2, 0xcc, 0x51, 0x52, 0x0c,
             0xde, 0x1e, 0xf7, 0xf1, 0xca, 0x90, 0x86, 0x72, 0xad, 0x67, 0xea, 0x89, 0x45, 0x44,
@@ -278,7 +195,8 @@ mod tests {
             0x2f, 0xde,
         ];
 
-        let buf: Vec<u8> = msg.into();
-        assert_eq!(msg, Initiation::try_from(&buf[..]).unwrap());
+        let buf: Vec<u8> = msg.as_bytes().to_vec();
+        let msg_p = Initiation::parse(&buf[..]).unwrap();
+        assert_eq!(msg, *msg_p.into_ref());
     }
 }
diff --git a/src/noise.rs b/src/noise.rs
index b45b690..1695627 100644
--- a/src/noise.rs
+++ b/src/noise.rs
@@ -1,5 +1,3 @@
-use std::convert::TryFrom;
-
 // DH
 use x25519_dalek::PublicKey;
 use x25519_dalek::StaticSecret;
@@ -17,6 +15,8 @@ use rand::rngs::OsRng;
 use generic_array::typenum::*;
 use generic_array::GenericArray;
 
+use zerocopy::AsBytes;
+
 use crate::device::Device;
 use crate::messages::{Initiation, Response};
 use crate::peer::{Peer, State};
@@ -148,7 +148,7 @@ pub fn create_initiation<T: Copy>(
     let hs = INITIAL_HS;
     let hs = HASH!(&hs, peer.pk.as_bytes());
 
-    msg.f_sender = sender;
+    msg.f_sender.set(sender);
 
     // (E_priv, E_pub) := DH-Generate()
 
@@ -214,7 +214,7 @@ pub fn create_initiation<T: Copy>(
 
     // return message as vector
 
-    Ok(Initiation::into(msg))
+    Ok(msg.as_bytes().to_vec())
 }
 
 pub fn consume_initiation<'a, T: Copy>(
@@ -223,7 +223,7 @@ pub fn consume_initiation<'a, T: Copy>(
 ) -> Result<(&'a Peer<T>, TemporaryState), HandshakeError> {
     // parse message
 
-    let msg = Initiation::try_from(msg)?;
+    let msg = Initiation::parse(msg)?;
 
     // initialize state
 
@@ -288,7 +288,7 @@ pub fn consume_initiation<'a, T: Copy>(
 
     // return state (to create response)
 
-    Ok((peer, (msg.f_sender, eph_r_pk, hs, ck)))
+    Ok((peer, (msg.f_sender.get(), eph_r_pk, hs, ck)))
 }
 
 pub fn create_response<T: Copy>(
@@ -301,8 +301,8 @@ pub fn create_response<T: Copy>(
 
     let (receiver, eph_r_pk, hs, ck) = state;
 
-    msg.f_sender = sender;
-    msg.f_receiver = receiver;
+    msg.f_sender.set(sender);
+    msg.f_receiver.set(receiver);
 
     // (E_priv, E_pub) := DH-Generate()
 
@@ -361,7 +361,7 @@ pub fn create_response<T: Copy>(
 
     Ok((
         peer.identifier,
-        Some(Response::into(msg)),
+        Some(msg.as_bytes().to_vec()),
         Some(KeyPair {
             confirmed: false,
             send: Key {
@@ -376,17 +376,15 @@ pub fn create_response<T: Copy>(
     ))
 }
 
-pub fn consume_response<T: Copy>(
-    device: &Device<T>,
-    msg: &[u8],
-) -> Result<Output<T>, HandshakeError> {
+pub fn consume_response<T: Copy>(device: &Device<T>, msg: &[u8]) -> Result<Output<T>, HandshakeError> {
+
     // parse message
 
-    let msg = Response::try_from(msg)?;
+    let msg = Response::parse(msg)?;
 
     // retrieve peer and associated state
 
-    let peer = device.lookup_id(msg.f_receiver)?;
+    let peer = device.lookup_id(msg.f_receiver.get())?;
     let (hs, ck, sender, eph_sk) = match peer.get_state() {
         State::Reset => Err(HandshakeError::InvalidState),
         State::InitiationSent {
@@ -448,7 +446,7 @@ pub fn consume_response<T: Copy>(
                 key: key_send.into(),
             },
             recv: Key {
-                id: msg.f_sender,
+                id: msg.f_sender.get(),
                 key: key_recv.into(),
             },
         }),