Revert removing ecies (#2009)

* revert removing ECIES without MAC

* removed reverted change in encrypt

Cargo.lock

@@ -290,7 +290,6 @@ version = "1.4.0"
 dependencies = [
  "clippy 0.0.85 (registry+https://github.com/rust-lang/crates.io-index)",
  "ethabi 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "ethcore-devtools 1.4.0",
  "ethcore-rpc 1.4.0",
  "ethcore-util 1.4.0",
  "hyper 0.9.4 (git+https://github.com/ethcore/hyper)",

ethcrypto/src/lib.rs

@@ -33,6 +33,7 @@ pub const KEY_LENGTH: usize = 32;
 pub const KEY_ITERATIONS: usize = 10240;
 pub const KEY_LENGTH_AES: usize = KEY_LENGTH / 2;
 
+#[derive(PartialEq, Debug)]
 pub enum Error {
 	Secp(SecpError),
 	InvalidMessage,
@@ -147,9 +148,9 @@ pub mod ecies {
 	use rcrypto::sha2::Sha256;
 	use rcrypto::hmac::Hmac;
 	use rcrypto::mac::Mac;
-	use bigint::hash::FixedHash;
+	use bigint::hash::{FixedHash, H128};
 	use ethkey::{Random, Generator, Public, Secret};
-	use {Error, ecdh, aes};
+	use {Error, ecdh, aes, Keccak256};
 
 	/// Encrypt a message with a public key
 	pub fn encrypt(public: &Public, shared_mac: &[u8], plain: &[u8]) -> Result<Vec<u8>, Error> {
@@ -169,9 +170,11 @@ pub mod ecies {
 		{
 			let msgd = &mut msg[1..];
 			msgd[0..64].copy_from_slice(r.public());
+			let iv = H128::random();
+			msgd[64..80].copy_from_slice(&iv);
 			{
 				let cipher = &mut msgd[(64 + 16)..(64 + 16 + plain.len())];
-				aes::encrypt(ekey, &[0u8; 16], plain, cipher);
+				aes::encrypt(ekey, &iv, plain, cipher);
 			}
 			let mut hmac = Hmac::new(Sha256::new(), &mkey);
 			{
@@ -184,6 +187,31 @@ pub mod ecies {
 		Ok(msg)
 	}
 
+	/// Encrypt a message with a public key
+	pub fn encrypt_single_message(public: &Public, plain: &[u8]) -> Result<Vec<u8>, Error> {
+		let r = Random.generate().unwrap();
+		let z = try!(ecdh::agree(r.secret(), public));
+		let mut key = [0u8; 32];
+		let mut mkey = [0u8; 32];
+		kdf(&z, &[0u8; 0], &mut key);
+		let mut hasher = Sha256::new();
+		let mkey_material = &key[16..32];
+		hasher.input(mkey_material);
+		hasher.result(&mut mkey);
+		let ekey = &key[0..16];
+
+		let mut msgd = vec![0u8; (64 + plain.len())];
+		{
+			r.public().copy_to(&mut msgd[0..64]);
+			let iv = H128::from_slice(&z.keccak256()[0..16]);
+			{
+				let cipher = &mut msgd[64..(64 + plain.len())];
+				aes::encrypt(ekey, &iv, plain, cipher);
+			}
+		}
+		Ok(msgd)
+	}
+
 	/// Decrypt a message with a secret key
 	pub fn decrypt(secret: &Secret, shared_mac: &[u8], encrypted: &[u8]) -> Result<Vec<u8>, Error> {
 		let meta_len = 1 + 64 + 16 + 32;
@@ -224,6 +252,33 @@ pub mod ecies {
 		Ok(msg)
 	}
 
+	/// Decrypt single message with a secret key
+	pub fn decrypt_single_message(secret: &Secret, encrypted: &[u8]) -> Result<Vec<u8>, Error> {
+		let meta_len = 64;
+		if encrypted.len() < meta_len {
+			return Err(Error::InvalidMessage); //invalid message: publickey
+		}
+
+		let e = encrypted;
+		let p = Public::from_slice(&e[0..64]);
+		let z = try!(ecdh::agree(secret, &p));
+		let mut key = [0u8; 32];
+		kdf(&z, &[0u8; 0], &mut key);
+		let ekey = &key[0..16];
+		let mkey_material = &key[16..32];
+		let mut hasher = Sha256::new();
+		let mut mkey = [0u8; 32];
+		hasher.input(mkey_material);
+		hasher.result(&mut mkey);
+
+		let clen = encrypted.len() - meta_len;
+		let cipher = &e[64..(64+clen)];
+		let mut msg = vec![0u8; clen];
+		let iv = H128::from_slice(&z.keccak256()[0..16]);
+		aes::decrypt(ekey, &iv, cipher, &mut msg[..]);
+		Ok(msg)
+	}
+
 	fn kdf(secret: &Secret, s1: &[u8], dest: &mut [u8]) {
 		let mut hasher = Sha256::new();
 		// SEC/ISO/Shoup specify counter size SHOULD be equivalent
@@ -244,3 +299,35 @@ pub mod ecies {
 	}
 }
 
+#[cfg(test)]
+mod tests {
+	use ethkey::{Random, Generator};
+	use ecies;
+
+	#[test]
+	fn ecies_shared() {
+		let kp = Random.generate().unwrap();
+		let message = b"So many books, so little time";
+
+		let shared = b"shared";
+		let wrong_shared = b"incorrect";
+		let encrypted = ecies::encrypt(kp.public(), shared, message).unwrap();
+		assert!(encrypted[..] != message[..]);
+		assert_eq!(encrypted[0], 0x04);
+
+		assert!(ecies::decrypt(kp.secret(), wrong_shared, &encrypted).is_err());
+		let decrypted = ecies::decrypt(kp.secret(), shared, &encrypted).unwrap();
+		assert_eq!(decrypted[..message.len()], message[..]);
+	}
+
+	#[test]
+	fn ecies_shared_single() {
+		let kp = Random.generate().unwrap();
+		let message = b"So many books, so little time";
+		let encrypted = ecies::encrypt_single_message(kp.public(), message).unwrap();
+		assert!(encrypted[..] != message[..]);
+		let decrypted = ecies::decrypt_single_message(kp.secret(), &encrypted).unwrap();
+		assert_eq!(decrypted[..message.len()], message[..]);
+	}
+}
+