Replace secp256k1 crate with libsecp256k1. (#1029)

* Replace `secp256k1` crate with `libsecp256k1`.

Unfortunately we could not implement `AsRef<[u8]>` for `SecretKey`
as the crate does not provide a means to do so.

* Fix `DecodingError` invocation.

* Remove the cc for wasm

* Revert "Remove the cc for wasm"

This reverts commit 3a19db35e62931c6e9ffbff6c21f9b0d7ae5403a.

* Fix CircleCI build

Cargo.toml

@@ -10,8 +10,8 @@ keywords = ["peer-to-peer", "libp2p", "networking"]
 categories = ["network-programming", "asynchronous"]
 
 [features]
-default = ["secio-secp256k1", "libp2p-websocket"]
-secio-secp256k1 = ["libp2p-secio/secp256k1"]
+default = ["secp256k1", "libp2p-websocket"]
+secp256k1 = ["libp2p-core/secp256k1", "libp2p-secio/secp256k1"]
 
 [dependencies]
 bytes = "0.4"

core/Cargo.toml

@@ -27,7 +27,7 @@ protobuf = "2.3"
 quick-error = "1.2"
 rand = "0.6"
 rw-stream-sink = { version = "0.1.1", path = "../misc/rw-stream-sink" }
-secp256k1 = { version = "0.12", features = ["rand"], optional = true }
+libsecp256k1 = { version = "0.2.2", optional = true }
 sha2 = "0.8.0"
 smallvec = "0.6"
 tokio-executor = "0.1.4"
@@ -57,3 +57,5 @@ tokio-mock-task = "0.1"
 
 [features]
 default = ["secp256k1"]
+secp256k1 = ["libsecp256k1"]
+

core/src/identity.rs

@@ -100,7 +100,7 @@ impl Keypair {
             #[cfg(not(any(target_os = "emscripten", target_os = "unknown")))]
             Rsa(ref pair) => pair.sign(msg),
             #[cfg(feature = "secp256k1")]
-            Secp256k1(ref pair) => Ok(pair.secret().sign(msg)),
+            Secp256k1(ref pair) => pair.secret().sign(msg)
         }
     }
 
@@ -178,7 +178,7 @@ impl PublicKey {
     pub fn from_protobuf_encoding(bytes: &[u8]) -> Result<PublicKey, DecodingError> {
         #[allow(unused_mut)] // Due to conditional compilation.
         let mut pubkey = protobuf::parse_from_bytes::<keys_proto::PublicKey>(bytes)
-            .map_err(|e| DecodingError::new("Protobuf", e))?;
+            .map_err(|e| DecodingError::new("Protobuf").source(e))?;
 
         match pubkey.get_Type() {
             keys_proto::KeyType::Ed25519 => {
@@ -193,7 +193,7 @@ impl PublicKey {
             #[cfg(any(target_os = "emscripten", target_os = "unknown"))]
             keys_proto::KeyType::RSA => {
                 log::debug!("support for RSA was disabled at compile-time");
-                Err("Unsupported".to_string().into())
+                Err(DecodingError::new("Unsupported"))
             },
             #[cfg(feature = "secp256k1")]
             keys_proto::KeyType::Secp256k1 => {

core/src/identity/ed25519.rs

@@ -46,7 +46,7 @@ impl Keypair {
     pub fn decode(kp: &mut [u8]) -> Result<Keypair, DecodingError> {
         ed25519::Keypair::from_bytes(kp)
             .map(|k| { kp.zeroize(); Keypair(k) })
-            .map_err(|e| DecodingError::new("Ed25519 keypair", e.compat()))
+            .map_err(|e| DecodingError::new("Ed25519 keypair").source(e.compat()))
     }
 
     /// Sign a message using the private key of this keypair.
@@ -112,7 +112,7 @@ impl PublicKey {
     /// Decode a public key from a byte array as produced by `encode`.
     pub fn decode(k: &[u8]) -> Result<PublicKey, DecodingError> {
         ed25519::PublicKey::from_bytes(k)
-            .map_err(|e| DecodingError::new("Ed25519 public key", e.compat()))
+            .map_err(|e| DecodingError::new("Ed25519 public key").source(e.compat()))
             .map(PublicKey)
     }
 }
@@ -147,7 +147,7 @@ impl SecretKey {
     pub fn from_bytes(mut sk_bytes: impl AsMut<[u8]>) -> Result<SecretKey, DecodingError> {
         let sk_bytes = sk_bytes.as_mut();
         let secret = ed25519::SecretKey::from_bytes(&*sk_bytes)
-            .map_err(|e| DecodingError::new("Ed25519 secret key", e.compat()))?;
+            .map_err(|e| DecodingError::new("Ed25519 secret key").source(e.compat()))?;
         sk_bytes.zeroize();
         Ok(SecretKey(secret))
     }

core/src/identity/error.rs

@@ -31,14 +31,12 @@ pub struct DecodingError {
 }
 
 impl DecodingError {
-    pub(crate) fn new(msg: &str, source: impl Error + Send + Sync + 'static) -> DecodingError {
-        DecodingError { msg: msg.to_string(), source: Some(Box::new(source)) }
-    }
+    pub(crate) fn new<S: ToString>(msg: S) -> Self {
+        Self { msg: msg.to_string(), source: None }
     }
 
-impl From<String> for DecodingError {
-    fn from(s: String) -> DecodingError {
-        DecodingError { msg: s, source: None }
+    pub(crate) fn source(self, source: impl Error + Send + Sync + 'static) -> Self {
+        Self { source: Some(Box::new(source)), .. self }
     }
 }
 
@@ -63,8 +61,12 @@ pub struct SigningError {
 
 /// An error during encoding of key material.
 impl SigningError {
-    pub(crate) fn new(msg: &str, source: impl Error + Send + Sync + 'static) -> SigningError {
-        SigningError { msg: msg.to_string(), source: Some(Box::new(source)) }
+    pub(crate) fn new<S: ToString>(msg: S) -> Self {
+        Self { msg: msg.to_string(), source: None }
+    }
+
+    pub(crate) fn source(self, source: impl Error + Send + Sync + 'static) -> Self {
+        Self { source: Some(Box::new(source)), .. self }
     }
 }
 
@@ -74,12 +76,6 @@ impl fmt::Display for SigningError {
     }
 }
 
-impl From<String> for SigningError {
-    fn from(s: String) -> SigningError {
-        SigningError { msg: s, source: None }
-    }
-}
-
 impl Error for SigningError {
     fn source(&self) -> Option<&(dyn Error + 'static)> {
         self.source.as_ref().map(|s| &**s as &dyn Error)

core/src/identity/rsa.rs

@@ -41,7 +41,7 @@ impl Keypair {
     /// [RFC5208]: https://tools.ietf.org/html/rfc5208#section-5
     pub fn from_pkcs8(der: &mut [u8]) -> Result<Keypair, DecodingError> {
         let kp = RsaKeyPair::from_pkcs8(Input::from(&der[..]))
-            .map_err(|e| DecodingError::new("RSA PKCS#8 PrivateKeyInfo", e))?;
+            .map_err(|e| DecodingError::new("RSA PKCS#8 PrivateKeyInfo").source(e))?;
         der.zeroize();
         Ok(Keypair(Arc::new(kp)))
     }
@@ -57,7 +57,7 @@ impl Keypair {
         let rng = SystemRandom::new();
         match self.0.sign(&RSA_PKCS1_SHA256, &rng, &data, &mut signature) {
             Ok(()) => Ok(signature),
-            Err(e) => Err(SigningError::new("RSA", e))
+            Err(e) => Err(SigningError::new("RSA").source(e))
         }
     }
 }
@@ -105,7 +105,7 @@ impl PublicKey {
     /// structure. See also `encode_x509`.
     pub fn decode_x509(pk: &[u8]) -> Result<PublicKey, DecodingError> {
         Asn1SubjectPublicKeyInfo::deserialize(pk.iter())
-            .map_err(|e| DecodingError::new("RSA X.509", e))
+            .map_err(|e| DecodingError::new("RSA X.509").source(e))
             .map(|spki| spki.subjectPublicKey.0)
     }
 }

core/src/identity/secp256k1.rs

@@ -21,18 +21,12 @@
 //! Secp256k1 keys.
 
 use asn1_der::{FromDerObject, DerObject};
-use lazy_static::lazy_static;
+use rand::RngCore;
 use sha2::{Digest as ShaDigestTrait, Sha256};
-use secp256k1 as secp;
-use secp::{Message, Signature};
-use super::error::DecodingError;
+use secp256k1::{Message, Signature};
+use super::error::{DecodingError, SigningError};
 use zeroize::Zeroize;
 
-// Cached `Secp256k1` context, to avoid recreating it every time.
-lazy_static! {
-    static ref SECP: secp::Secp256k1<secp::All> = secp::Secp256k1::new();
-}
-
 /// A Secp256k1 keypair.
 #[derive(Clone)]
 pub struct Keypair {
@@ -60,7 +54,7 @@ impl Keypair {
 /// Promote a Secp256k1 secret key into a keypair.
 impl From<SecretKey> for Keypair {
     fn from(secret: SecretKey) -> Keypair {
-        let public = PublicKey(secp::key::PublicKey::from_secret_key(&SECP, &secret.0));
+        let public = PublicKey(secp256k1::PublicKey::from_secret_key(&secret.0));
         Keypair { secret, public }
     }
 }
@@ -74,19 +68,21 @@ impl From<Keypair> for SecretKey {
 
 /// A Secp256k1 secret key.
 #[derive(Clone)]
-pub struct SecretKey(secp::key::SecretKey);
-
-/// View the bytes of the secret key.
-impl AsRef<[u8]> for SecretKey {
-    fn as_ref(&self) -> &[u8] {
-        &self.0[..]
-    }
-}
+pub struct SecretKey(secp256k1::SecretKey);
 
 impl SecretKey {
     /// Generate a new Secp256k1 secret key.
     pub fn generate() -> SecretKey {
-        SecretKey(secp::key::SecretKey::new(&mut secp::rand::thread_rng()))
+        let mut r = rand::thread_rng();
+        let mut b = [0; secp256k1::util::SECRET_KEY_SIZE];
+        // This is how it is done in `secp256k1::SecretKey::random` which
+        // we do not use here because it uses `rand::Rng` from rand-0.4.
+        loop {
+            r.fill_bytes(&mut b);
+            if let Ok(k) = secp256k1::SecretKey::parse(&b) {
+                return SecretKey(k)
+            }
+        }
     }
 
     /// Create a secret key from a byte slice, zeroing the slice on success.
@@ -94,8 +90,8 @@ impl SecretKey {
     /// error is returned.
     pub fn from_bytes(mut sk: impl AsMut<[u8]>) -> Result<SecretKey, DecodingError> {
         let sk_bytes = sk.as_mut();
-        let secret = secp::key::SecretKey::from_slice(&*sk_bytes)
-            .map_err(|e| DecodingError::new("Secp256k1 secret key", e))?;
+        let secret = secp256k1::SecretKey::parse_slice(&*sk_bytes)
+            .map_err(|_| DecodingError::new("failed to parse secp256k1 secret key"))?;
         sk_bytes.zeroize();
         Ok(SecretKey(secret))
     }
@@ -108,12 +104,12 @@ impl SecretKey {
         // TODO: Stricter parsing.
         let der_obj = der.as_mut();
         let obj: Vec<DerObject> = FromDerObject::deserialize((&*der_obj).iter())
-            .map_err(|e| DecodingError::new("Secp256k1 DER ECPrivateKey", e))?;
+            .map_err(|e| DecodingError::new("Secp256k1 DER ECPrivateKey").source(e))?;
         der_obj.zeroize();
         let sk_obj = obj.into_iter().nth(1)
-            .ok_or_else(|| "Not enough elements in DER".to_string())?;
+            .ok_or_else(|| DecodingError::new("Not enough elements in DER"))?;
         let mut sk_bytes: Vec<u8> = FromDerObject::from_der_object(sk_obj)
-            .map_err(|e| e.to_string())?;
+            .map_err(DecodingError::new)?;
         let sk = SecretKey::from_bytes(&mut sk_bytes)?;
         sk_bytes.zeroize();
         Ok(sk)
@@ -123,36 +119,38 @@ impl SecretKey {
     /// ECDSA signature, as defined in [RFC3278].
     ///
     /// [RFC3278]: https://tools.ietf.org/html/rfc3278#section-8.2
-    pub fn sign(&self, msg: &[u8]) -> Vec<u8> {
-        let m = Message::from_slice(Sha256::digest(&msg).as_ref())
-            .expect("digest output length doesn't match secp256k1 input length");
-        SECP.sign(&m, &self.0).serialize_der()
+    pub fn sign(&self, msg: &[u8]) -> Result<Vec<u8>, SigningError> {
+        let m = Message::parse_slice(Sha256::digest(msg).as_ref())
+            .map_err(|_| SigningError::new("failed to parse secp256k1 digest"))?;
+        secp256k1::sign(&m, &self.0)
+            .map(|s| s.0.serialize_der().as_ref().into())
+            .map_err(|_| SigningError::new("failed to create secp256k1 signature"))
     }
 }
 
 /// A Secp256k1 public key.
 #[derive(PartialEq, Eq, Clone, Debug)]
-pub struct PublicKey(secp::key::PublicKey);
+pub struct PublicKey(secp256k1::PublicKey);
 
 impl PublicKey {
     /// Verify the Secp256k1 signature on a message using the public key.
     pub fn verify(&self, msg: &[u8], sig: &[u8]) -> bool {
-        Message::from_slice(&Sha256::digest(msg))
-            .and_then(|m| Signature::from_der(sig)
-                .and_then(|s| SECP.verify(&m, &s, &self.0))).is_ok()
+        Message::parse_slice(Sha256::digest(msg).as_ref())
+            .and_then(|m| Signature::parse_der(sig).map(|s| secp256k1::verify(&m, &s, &self.0)))
+            .unwrap_or(false)
     }
 
     /// Encode the public key in compressed form, i.e. with one coordinate
     /// represented by a single bit.
     pub fn encode(&self) -> [u8; 33] {
-        self.0.serialize()
+        self.0.serialize_compressed()
     }
 
     /// Decode a public key from a byte slice in the the format produced
     /// by `encode`.
     pub fn decode(k: &[u8]) -> Result<PublicKey, DecodingError> {
-        secp256k1::PublicKey::from_slice(k)
-            .map_err(|e| DecodingError::new("Secp256k1 public key", e))
+        secp256k1::PublicKey::parse_slice(k, Some(secp256k1::PublicKeyFormat::Compressed))
+            .map_err(|_| DecodingError::new("failed to parse secp256k1 public key"))
             .map(PublicKey)
     }
 }
@@ -165,9 +163,9 @@ mod tests {
     fn secp256k1_secret_from_bytes() {
         let sk1 = SecretKey::generate();
         let mut sk_bytes = [0; 32];
-        sk_bytes.copy_from_slice(sk1.as_ref());
+        sk_bytes.copy_from_slice(&sk1.0.serialize()[..]);
         let sk2 = SecretKey::from_bytes(&mut sk_bytes).unwrap();
-        assert_eq!(sk1.as_ref(), sk2.as_ref());
+        assert_eq!(sk1.0.serialize(), sk2.0.serialize());
         assert_eq!(sk_bytes, [0; 32]);
     }
 }

protocols/secio/Cargo.toml

@@ -17,7 +17,6 @@ libp2p-core = { version = "0.7.0", path = "../../core" }
 log = "0.4.6"
 protobuf = "2.3"
 rand = "0.6.5"
-secp256k1 = { version = "0.12", features = ["rand"], optional = true }
 aes-ctr = "0.3"
 aesni = { version = "0.6", features = ["nocheck"], optional = true }
 twofish = "0.2.0"
@@ -41,6 +40,7 @@ web-sys = { version = "0.3.10", features = ["Crypto", "CryptoKey", "SubtleCrypto
 
 [features]
 default = ["secp256k1"]
+secp256k1 = []
 aes-all = ["aesni"]
 
 [dev-dependencies]