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use std::iter::repeat;
use ethkey::Secret;
use {json, Error, crypto};
use crypto::Keccak256;
use random::Random;
use smallvec::SmallVec;
use account::{Cipher, Kdf, Aes128Ctr, Pbkdf2, Prf};
#[derive(Debug, PartialEq, Clone)]
pub struct Crypto {
pub cipher: Cipher,
pub ciphertext: Vec<u8>,
pub kdf: Kdf,
pub mac: [u8; 32],
}
impl From<json::Crypto> for Crypto {
fn from(json: json::Crypto) -> Self {
Crypto {
cipher: json.cipher.into(),
ciphertext: json.ciphertext.into(),
kdf: json.kdf.into(),
mac: json.mac.into(),
}
}
}
impl Into<json::Crypto> for Crypto {
fn into(self) -> json::Crypto {
json::Crypto {
cipher: self.cipher.into(),
ciphertext: self.ciphertext.into(),
kdf: self.kdf.into(),
mac: self.mac.into(),
}
}
}
impl Crypto {
pub fn with_secret(secret: &Secret, password: &str, iterations: u32) -> Self {
Crypto::with_plain(&*secret, password, iterations)
}
pub fn with_plain(plain: &[u8], password: &str, iterations: u32) -> Self {
let salt: [u8; 32] = Random::random();
let iv: [u8; 16] = Random::random();
let (derived_left_bits, derived_right_bits) = crypto::derive_key_iterations(password, &salt, iterations);
let plain_len = plain.len();
let mut ciphertext: SmallVec<[u8; 32]> = SmallVec::new();
ciphertext.grow(plain_len);
ciphertext.extend(repeat(0).take(plain_len));
crypto::aes::encrypt(&derived_left_bits, &iv, plain, &mut *ciphertext);
let mac = crypto::derive_mac(&derived_right_bits, &*ciphertext).keccak256();
Crypto {
cipher: Cipher::Aes128Ctr(Aes128Ctr {
iv: iv,
}),
ciphertext: (*ciphertext).to_vec(),
kdf: Kdf::Pbkdf2(Pbkdf2 {
dklen: crypto::KEY_LENGTH as u32,
salt: salt,
c: iterations,
prf: Prf::HmacSha256,
}),
mac: mac,
}
}
pub fn secret(&self, password: &str) -> Result<Secret, Error> {
if self.ciphertext.len() > 32 {
return Err(Error::InvalidSecret);
}
let secret = self.do_decrypt(password, 32)?;
Ok(Secret::from_slice(&secret)?)
}
pub fn decrypt(&self, password: &str) -> Result<Vec<u8>, Error> {
let expected_len = self.ciphertext.len();
self.do_decrypt(password, expected_len)
}
fn do_decrypt(&self, password: &str, expected_len: usize) -> Result<Vec<u8>, Error> {
let (derived_left_bits, derived_right_bits) = match self.kdf {
Kdf::Pbkdf2(ref params) => crypto::derive_key_iterations(password, ¶ms.salt, params.c),
Kdf::Scrypt(ref params) => crypto::derive_key_scrypt(password, ¶ms.salt, params.n, params.p, params.r)?,
};
let mac = crypto::derive_mac(&derived_right_bits, &self.ciphertext).keccak256();
if mac != self.mac {
return Err(Error::InvalidPassword);
}
let mut plain: SmallVec<[u8; 32]> = SmallVec::new();
plain.grow(expected_len);
plain.extend(repeat(0).take(expected_len));
match self.cipher {
Cipher::Aes128Ctr(ref params) => {
debug_assert!(expected_len >= self.ciphertext.len());
let from = expected_len - self.ciphertext.len();
crypto::aes::decrypt(&derived_left_bits, ¶ms.iv, &self.ciphertext, &mut plain[from..]);
Ok(plain.into_iter().collect())
},
}
}
}
#[cfg(test)]
mod tests {
use ethkey::{Generator, Random};
use super::Crypto;
#[test]
fn crypto_with_secret_create() {
let keypair = Random.generate().unwrap();
let crypto = Crypto::with_secret(keypair.secret(), "this is sparta", 10240);
let secret = crypto.secret("this is sparta").unwrap();
assert_eq!(keypair.secret(), &secret);
}
#[test]
#[should_panic]
fn crypto_with_secret_invalid_password() {
let keypair = Random.generate().unwrap();
let crypto = Crypto::with_secret(keypair.secret(), "this is sparta", 10240);
let _ = crypto.secret("this is sparta!").unwrap();
}
#[test]
fn crypto_with_null_plain_data() {
let original_data = b"";
let crypto = Crypto::with_plain(&original_data[..], "this is sparta", 10240);
let decrypted_data = crypto.decrypt("this is sparta").unwrap();
assert_eq!(original_data[..], *decrypted_data);
}
#[test]
fn crypto_with_tiny_plain_data() {
let original_data = b"{}";
let crypto = Crypto::with_plain(&original_data[..], "this is sparta", 10240);
let decrypted_data = crypto.decrypt("this is sparta").unwrap();
assert_eq!(original_data[..], *decrypted_data);
}
#[test]
fn crypto_with_huge_plain_data() {
let original_data: Vec<_> = (1..65536).map(|i| (i % 256) as u8).collect();
let crypto = Crypto::with_plain(&original_data, "this is sparta", 10240);
let decrypted_data = crypto.decrypt("this is sparta").unwrap();
assert_eq!(&original_data, &decrypted_data);
}
}