This crate contains generic implementation of block cipher modes of operation.

Note that this crate implements only modes which require padding. For CTR, CFB and OFB modes (i.e. modes which transsform block ciphers into stream ciphers) see crates in the RustCrypto/stream-ciphers repository.

Usage example

#[macro_use] extern crate hex_literal;
extern crate aes_soft as aes;
extern crate block_modes;

use block_modes::{BlockMode, Cbc};
use block_modes::block_padding::Pkcs7;
use aes::Aes128;

// create an alias for convinience
type Aes128Cbc = Cbc<Aes128, Pkcs7>;

let key = hex!("000102030405060708090a0b0c0d0e0f");
let iv = hex!("f0f1f2f3f4f5f6f7f8f9fafbfcfdfeff");
let plaintext = b"Hello world!";
let cipher = Aes128Cbc::new_var(&key, &iv).unwrap();

// buffer must have enough space for message+padding
let mut buffer = [0u8; 32];
// copy message to the buffer
let pos = plaintext.len();
buffer[..pos].copy_from_slice(plaintext);
let ciphertext = cipher.encrypt(&mut buffer, pos).unwrap();

assert_eq!(ciphertext, hex!("1b7a4c403124ae2fb52bedc534d82fa8"));

// re-create cipher mode instance
let cipher = Aes128Cbc::new_var(&key, &iv).unwrap();
let mut buf = ciphertext.to_vec();
let decrypted_ciphertext = cipher.decrypt(&mut buf).unwrap();

assert_eq!(decrypted_ciphertext, plaintext);

With an enabled std feature (which is enabled by default) you can use encrypt_vec and descrypt_vec methods:

# #[macro_use] extern crate hex_literal;
# extern crate aes_soft as aes;
# extern crate block_modes;
#
# use block_modes::{BlockMode, Cbc};
# use block_modes::block_padding::Pkcs7;
# use aes::Aes128;
#
# // create an alias for convinience
# type Aes128Cbc = Cbc<Aes128, Pkcs7>;
#
# let key = hex!("000102030405060708090a0b0c0d0e0f");
# let iv = hex!("f0f1f2f3f4f5f6f7f8f9fafbfcfdfeff");
# let plaintext = b"Hello world!";
let cipher = Aes128Cbc::new_var(&key, &iv).unwrap();
let ciphertext = cipher.encrypt_vec(plaintext);

assert_eq!(ciphertext, hex!("1b7a4c403124ae2fb52bedc534d82fa8"));

let cipher = Aes128Cbc::new_var(&key, &iv).unwrap();
let decrypted_ciphertext = cipher.decrypt_vec(&ciphertext).unwrap();

assert_eq!(decrypted_ciphertext, plaintext);