Support external eth_sign (#5481)

* Display a QR for eth_sign requests.

* Support raw confirmation of eth_sign

* Fix ethkey issue on nightly.

* Fixing test.

* Fixing test.

ethkey/src/brain.rs

@@ -57,8 +57,8 @@ mod tests {
 	#[test]
 	fn test_brain() {
 		let words = "this is sparta!".to_owned();
-		let first_keypair = Brain(words.clone()).generate().unwrap();
-		let second_keypair = Brain(words.clone()).generate().unwrap();
+		let first_keypair = Brain::new(words.clone()).generate().unwrap();
+		let second_keypair = Brain::new(words.clone()).generate().unwrap();
 		assert_eq!(first_keypair.secret(), second_keypair.secret());
 	}
 }

ethkey/src/signature.rs

@@ -25,6 +25,7 @@ use rustc_serialize::hex::{ToHex, FromHex};
 use bigint::hash::{H520, H256};
 use {Secret, Public, SECP256K1, Error, Message, public_to_address, Address};
 
+/// Signature encoded as RSV components
 #[repr(C)]
 pub struct Signature([u8; 65]);
 
@@ -44,8 +45,32 @@ impl Signature {
 		self.0[64]
 	}
 
+	/// Encode the signature into VRS array (V altered to be in "Electrum" notation).
+	pub fn into_vrs(self) -> [u8; 65] {
+		let mut vrs = [0u8; 65];
+		vrs[0] = self.v() + 27;
+		vrs[1..33].copy_from_slice(self.r());
+		vrs[33..65].copy_from_slice(self.s());
+		vrs
+	}
+
+	/// Parse bytes as a signature encoded as VRS (V in "Electrum" notation).
+	/// May return empty (invalid) signature if given data has invalid length.
+	pub fn from_vrs(data: &[u8]) -> Self {
+		if data.len() != 65 || data[0] < 27 {
+			// fallback to empty (invalid) signature
+			return Signature::default();
+		}
+
+		let mut sig = [0u8; 65];
+		sig[0..32].copy_from_slice(&data[1..33]);
+		sig[32..64].copy_from_slice(&data[33..65]);
+		sig[64] = data[0] - 27;
+		Signature(sig)
+	}
+
 	/// Create a signature object from the sig.
-	pub fn from_rsv(r: &H256, s: &H256, v: u8) -> Signature {
+	pub fn from_rsv(r: &H256, s: &H256, v: u8) -> Self {
 		let mut sig = [0u8; 65];
 		sig[0..32].copy_from_slice(&r);
 		sig[32..64].copy_from_slice(&s);
@@ -222,6 +247,21 @@ mod tests {
 	use {Generator, Random, Message};
 	use super::{sign, verify_public, verify_address, recover, Signature};
 
+	#[test]
+	fn vrs_conversion() {
+		// given
+		let keypair = Random.generate().unwrap();
+		let message = Message::default();
+		let signature = sign(keypair.secret(), &message).unwrap();
+
+		// when
+		let vrs = signature.clone().into_vrs();
+		let from_vrs = Signature::from_vrs(&vrs);
+
+		// then
+		assert_eq!(signature, from_vrs);
+	}
+
 	#[test]
 	fn signature_to_and_from_str() {
 		let keypair = Random.generate().unwrap();