src/crypto.rs

   1 use std::rand::{ OsRng, Rng };
   2 use std::io::IoResult;
   3 use std::slice::bytes::copy_memory;
   4 use openssl::crypto::hash::SHA256;
   5 use openssl::crypto::hmac::HMAC;
   6 use openssl::crypto::symm;
   7
   8 static KEY_A: &'static [u8] = [125, 31, 131, 118, 143, 180, 252, 53, 211, 217, 79, 240, 128, 91, 252, 87, 104, 236, 145, 198, 163, 203, 161, 12, 53, 56, 218, 40, 221, 95, 171, 140];
   9 static KEY_C: &'static [u8] = [75, 226, 88, 31, 223, 216, 182, 216, 178, 58, 59, 193, 245, 80, 254, 128, 125, 246, 246, 224, 194, 190, 123, 123, 10, 131, 217, 183, 112, 157, 166, 102];
  10
  11 pub fn compute_mac(data: &[u8]) -> [u8, ..10] {
  12    let mut hmac = HMAC(SHA256, KEY_A);
  13    hmac.update(data);
  14    let mut result = [0u8, ..10];
  15    copy_memory(&mut result, hmac.finalize().slice(0, 10));
  16    result
  17 }
  18
  19 pub fn encrypt(plaindata: &[u8], iv: &[u8]) -> Option<Vec<u8>> {
  20    let c = symm::Crypter::new(symm::AES_256_CBC);
  21    c.init(symm::Encrypt, KEY_C, iv.to_vec());
  22    c.pad(false); // Padding disabled!
  23    let mut r = c.update(plaindata);
  24    let rest = c.finalize();
  25    if rest.is_empty() {
  26       Some(r)
  27    } else {
  28       None
  29    }
  30 }
  31
  32 pub fn decrypt(cypherdata: &[u8], iv: &[u8]) -> Option<Vec<u8>> {
  33    let c = symm::Crypter::new(symm::AES_256_CBC);
  34    c.init(symm::Decrypt, KEY_C, iv.to_vec());
  35    c.pad(false); // Padding disabled!
  36    let mut r = c.update(cypherdata);
  37    let rest = c.finalize();
  38    if rest.is_empty() {
  39       Some(r)
  40    } else {
  41       None
  42    }
  43 }
  44
  45 pub fn generate_key(size_byte: uint) -> IoResult<Vec<u8>>  {
  46    let mut bytes = Vec::from_elem(size_byte, 0u8);
  47    let mut generator = try!(OsRng::new()); // Uses '/dev/urandom' on Unix-like systems.
  48    generator.fill_bytes(bytes.as_mut_slice_());
  49    Ok(bytes)
  50 }