openethereum/ethcrypto/src/lib.rs
2016-11-17 15:30:08 +03:00

387 lines
12 KiB
Rust

// Copyright 2015, 2016 Ethcore (UK) Ltd.
// This file is part of Parity.
// Parity is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
// Parity is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// You should have received a copy of the GNU General Public License
// along with Parity. If not, see <http://www.gnu.org/licenses/>.
//! Crypto utils used ethstore and network.
extern crate ethcore_bigint as bigint;
extern crate tiny_keccak;
extern crate crypto as rcrypto;
extern crate secp256k1;
extern crate ethkey;
use std::fmt;
use tiny_keccak::Keccak;
use rcrypto::pbkdf2::pbkdf2;
use rcrypto::scrypt::{scrypt, ScryptParams};
use rcrypto::sha2::Sha256;
use rcrypto::hmac::Hmac;
use secp256k1::Error as SecpError;
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 ScryptError {
// log(N) < r / 16
InvalidN,
// p <= (2^31-1 * 32)/(128 * r)
InvalidP,
}
impl fmt::Display for ScryptError {
fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
let s = match *self {
ScryptError::InvalidN => "Invalid N argument of the scrypt encryption" ,
ScryptError::InvalidP => "Invalid p argument of the scrypt encryption",
};
write!(f, "{}", s)
}
}
#[derive(PartialEq, Debug)]
pub enum Error {
Secp(SecpError),
Scrypt(ScryptError),
InvalidMessage,
}
impl From<ScryptError> for Error {
fn from(err: ScryptError) -> Self {
Error::Scrypt(err)
}
}
impl fmt::Display for Error {
fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
let s = match *self {
Error::Secp(ref err) => err.to_string(),
Error::Scrypt(ref err) => err.to_string(),
Error::InvalidMessage => "Invalid message".into(),
};
write!(f, "{}", s)
}
}
impl From<SecpError> for Error {
fn from(e: SecpError) -> Self {
Error::Secp(e)
}
}
pub trait Keccak256<T> {
fn keccak256(&self) -> T where T: Sized;
}
impl Keccak256<[u8; 32]> for [u8] {
fn keccak256(&self) -> [u8; 32] {
let mut keccak = Keccak::new_keccak256();
let mut result = [0u8; 32];
keccak.update(self);
keccak.finalize(&mut result);
result
}
}
pub fn derive_key_iterations(password: &str, salt: &[u8; 32], c: u32) -> (Vec<u8>, Vec<u8>) {
let mut h_mac = Hmac::new(Sha256::new(), password.as_bytes());
let mut derived_key = vec![0u8; KEY_LENGTH];
pbkdf2(&mut h_mac, salt, c, &mut derived_key);
let derived_right_bits = &derived_key[0..KEY_LENGTH_AES];
let derived_left_bits = &derived_key[KEY_LENGTH_AES..KEY_LENGTH];
(derived_right_bits.to_vec(), derived_left_bits.to_vec())
}
pub fn derive_key_scrypt(password: &str, salt: &[u8; 32], n: u32, p: u32, r: u32) -> Result<(Vec<u8>, Vec<u8>), Error> {
// sanity checks
let log_n = (32 - n.leading_zeros() - 1) as u8;
if log_n as u32 >= r * 16 {
return Err(Error::Scrypt(ScryptError::InvalidN));
}
if p as u64 > ((u32::max_value() as u64 - 1) * 32)/(128 * (r as u64)) {
return Err(Error::Scrypt(ScryptError::InvalidP));
}
let mut derived_key = vec![0u8; KEY_LENGTH];
let scrypt_params = ScryptParams::new(log_n, r, p);
scrypt(password.as_bytes(), salt, &scrypt_params, &mut derived_key);
let derived_right_bits = &derived_key[0..KEY_LENGTH_AES];
let derived_left_bits = &derived_key[KEY_LENGTH_AES..KEY_LENGTH];
Ok((derived_right_bits.to_vec(), derived_left_bits.to_vec()))
}
pub fn derive_mac(derived_left_bits: &[u8], cipher_text: &[u8]) -> Vec<u8> {
let mut mac = vec![0u8; KEY_LENGTH_AES + cipher_text.len()];
mac[0..KEY_LENGTH_AES].copy_from_slice(derived_left_bits);
mac[KEY_LENGTH_AES..cipher_text.len() + KEY_LENGTH_AES].copy_from_slice(cipher_text);
mac
}
/// AES encryption
pub mod aes {
use rcrypto::blockmodes::{CtrMode, CbcDecryptor, PkcsPadding};
use rcrypto::aessafe::{AesSafe128Encryptor, AesSafe128Decryptor};
use rcrypto::symmetriccipher::{Encryptor, Decryptor, SymmetricCipherError};
use rcrypto::buffer::{RefReadBuffer, RefWriteBuffer, WriteBuffer};
/// Encrypt a message
pub fn encrypt(k: &[u8], iv: &[u8], plain: &[u8], dest: &mut [u8]) {
let mut encryptor = CtrMode::new(AesSafe128Encryptor::new(k), iv.to_vec());
encryptor.encrypt(&mut RefReadBuffer::new(plain), &mut RefWriteBuffer::new(dest), true).expect("Invalid length or padding");
}
/// Decrypt a message
pub fn decrypt(k: &[u8], iv: &[u8], encrypted: &[u8], dest: &mut [u8]) {
let mut encryptor = CtrMode::new(AesSafe128Encryptor::new(k), iv.to_vec());
encryptor.decrypt(&mut RefReadBuffer::new(encrypted), &mut RefWriteBuffer::new(dest), true).expect("Invalid length or padding");
}
/// Decrypt a message using cbc mode
pub fn decrypt_cbc(k: &[u8], iv: &[u8], encrypted: &[u8], dest: &mut [u8]) -> Result<usize, SymmetricCipherError> {
let mut encryptor = CbcDecryptor::new(AesSafe128Decryptor::new(k), PkcsPadding, iv.to_vec());
let len = dest.len();
let mut buffer = RefWriteBuffer::new(dest);
try!(encryptor.decrypt(&mut RefReadBuffer::new(encrypted), &mut buffer, true));
Ok(len - buffer.remaining())
}
}
/// ECDH functions
#[cfg_attr(feature="dev", allow(similar_names))]
pub mod ecdh {
use secp256k1::{ecdh, key};
use ethkey::{Secret, Public, SECP256K1};
use Error;
/// Agree on a shared secret
pub fn agree(secret: &Secret, public: &Public) -> Result<Secret, Error> {
let context = &SECP256K1;
let pdata = {
let mut temp = [4u8; 65];
(&mut temp[1..65]).copy_from_slice(&public[0..64]);
temp
};
let publ = try!(key::PublicKey::from_slice(context, &pdata));
// no way to create SecretKey from raw byte array.
let sec: &key::SecretKey = unsafe { ::std::mem::transmute(secret) };
let shared = ecdh::SharedSecret::new_raw(context, &publ, sec);
let mut s = Secret::default();
s.copy_from_slice(&shared[0..32]);
Ok(s)
}
}
/// ECIES function
#[cfg_attr(feature="dev", allow(similar_names))]
pub mod ecies {
use rcrypto::digest::Digest;
use rcrypto::sha2::Sha256;
use rcrypto::hmac::Hmac;
use rcrypto::mac::Mac;
use bigint::hash::{FixedHash, H128};
use ethkey::{Random, Generator, Public, Secret};
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> {
let r = Random.generate()
.expect("context known to have key-generation capabilities; qed");
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 msg = vec![0u8; (1 + 64 + 16 + plain.len() + 32)];
msg[0] = 0x04u8;
{
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, &iv, plain, cipher);
}
let mut hmac = Hmac::new(Sha256::new(), &mkey);
{
let cipher_iv = &msgd[64..(64 + 16 + plain.len())];
hmac.input(cipher_iv);
}
hmac.input(shared_mac);
hmac.raw_result(&mut msgd[(64 + 16 + plain.len())..]);
}
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()
.expect("context known to have key-generation capabilities");
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;
if encrypted.len() < meta_len || encrypted[0] < 2 || encrypted[0] > 4 {
return Err(Error::InvalidMessage); //invalid message: publickey
}
let e = &encrypted[1..];
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_with_iv = &e[64..(64+16+clen)];
let cipher_iv = &cipher_with_iv[0..16];
let cipher_no_iv = &cipher_with_iv[16..];
let msg_mac = &e[(64+16+clen)..];
// Verify tag
let mut hmac = Hmac::new(Sha256::new(), &mkey);
hmac.input(cipher_with_iv);
hmac.input(shared_mac);
let mut mac = [0u8; 32];
hmac.raw_result(&mut mac);
if &mac[..] != msg_mac {
return Err(Error::InvalidMessage);
}
let mut msg = vec![0u8; clen];
aes::decrypt(ekey, cipher_iv, cipher_no_iv, &mut msg[..]);
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
// to size of hash output, however, it also notes that
// the 4 bytes is okay. NIST specifies 4 bytes.
let mut ctr = 1u32;
let mut written = 0usize;
while written < dest.len() {
let ctrs = [(ctr >> 24) as u8, (ctr >> 16) as u8, (ctr >> 8) as u8, ctr as u8];
hasher.input(&ctrs);
hasher.input(secret);
hasher.input(s1);
hasher.result(&mut dest[written..(written + 32)]);
hasher.reset();
written += 32;
ctr += 1;
}
}
}
#[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[..]);
}
}