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import libc::c_int;
export crypter;
export cryptermode;
export encryptmode, decryptmode;
export cryptertype;
export aes_256_ecb, aes_256_cbc;
export encrypt, decrypt;
export libcrypto;
type EVP_CIPHER_CTX = *libc::c_void;
type EVP_CIPHER = *libc::c_void;
#[link_name = "crypto"]
#[abi = "cdecl"]
extern mod libcrypto {
fn EVP_CIPHER_CTX_new() -> EVP_CIPHER_CTX;
fn EVP_CIPHER_CTX_set_padding(ctx: EVP_CIPHER_CTX, padding: c_int);
fn EVP_aes_128_ecb() -> EVP_CIPHER;
fn EVP_aes_128_cbc() -> EVP_CIPHER;
fn EVP_aes_192_ecb() -> EVP_CIPHER;
fn EVP_aes_192_cbc() -> EVP_CIPHER;
fn EVP_aes_256_ecb() -> EVP_CIPHER;
fn EVP_aes_256_cbc() -> EVP_CIPHER;
fn EVP_CipherInit(ctx: EVP_CIPHER_CTX, evp: EVP_CIPHER,
key: *u8, iv: *u8, mode: c_int);
fn EVP_CipherUpdate(ctx: EVP_CIPHER_CTX, outbuf: *u8, outlen: *u32,
inbuf: *u8, inlen: u32);
fn EVP_CipherFinal(ctx: EVP_CIPHER_CTX, res: *u8, len: *u32);
}
#[doc = "Represents a symmetric cipher context."]
iface crypter {
#[doc = "
Enables or disables padding. If padding is disabled, total amount of data
encrypted must be a multiple of block size.
"]
fn pad(padding: bool);
#[doc = "Initializes this crypter."]
fn init(mode: cryptermode, key: ~[u8], iv: ~[u8]);
#[doc = "
Update this crypter with more data to encrypt or decrypt. Returns encrypted
or decrypted bytes.
"]
fn update(data: ~[u8]) -> ~[u8];
#[doc = "
Finish crypting. Returns the remaining partial block of output, if any.
"]
fn final() -> ~[u8];
}
enum cryptermode {
encryptmode,
decryptmode
}
enum cryptertype {
aes_256_ecb,
aes_256_cbc
}
fn evpc(t: cryptertype) -> (EVP_CIPHER, uint, uint) {
alt t {
aes_256_ecb { (libcrypto::EVP_aes_256_ecb(), 32u, 16u) }
aes_256_cbc { (libcrypto::EVP_aes_256_cbc(), 32u, 16u) }
}
}
fn crypter(t: cryptertype) -> crypter {
type crypterstate = {
evp: EVP_CIPHER,
ctx: EVP_CIPHER_CTX,
keylen: uint,
blocksize: uint
};
impl of crypter for crypterstate {
fn pad(padding: bool) {
let v = if padding { 1 } else { 0} as c_int;
libcrypto::EVP_CIPHER_CTX_set_padding(self.ctx, v);
}
fn init (mode: cryptermode, key: ~[u8], iv: ~[u8]) unsafe {
let m = alt mode { encryptmode { 1 } decryptmode { 0 } } as c_int;
assert(vec::len(key) == self.keylen);
let pkey: *u8 = vec::unsafe::to_ptr::<u8>(key);
let piv: *u8 = vec::unsafe::to_ptr::<u8>(iv);
libcrypto::EVP_CipherInit(self.ctx, self.evp, pkey, piv, m);
}
fn update(data: ~[u8]) -> ~[u8] unsafe {
let pdata = vec::unsafe::to_ptr::<u8>(data);
let datalen = vec::len(data) as u32;
let reslen = datalen + (self.blocksize as u32);
let preslen = ptr::addr_of(reslen);
let res = vec::to_mut(vec::from_elem::<u8>(reslen as uint, 0u8));
let pres = vec::unsafe::to_ptr::<u8>(res);
libcrypto::EVP_CipherUpdate(self.ctx, pres, preslen, pdata, datalen);
ret vec::slice::<u8>(res, 0u, *preslen as uint);
}
fn final() -> ~[u8] unsafe {
let reslen = self.blocksize as u32;
let preslen = ptr::addr_of(reslen);
let res = vec::to_mut(vec::from_elem::<u8>(reslen as uint, 0u8));
let pres = vec::unsafe::to_ptr::<u8>(res);
libcrypto::EVP_CipherFinal(self.ctx, pres, preslen);
ret vec::slice::<u8>(res, 0u, *preslen as uint);
}
}
let ctx = libcrypto::EVP_CIPHER_CTX_new();
let (evp, keylen, blocksz) = evpc(t);
let st = { evp: evp, ctx: ctx, keylen: keylen, blocksize: blocksz };
let h = st as crypter;
ret h;
}
#[doc = "
Encrypts data, using the specified crypter type in encrypt mode with the
specified key and iv; returns the resulting (encrypted) data.
"]
fn encrypt(t: cryptertype, key: ~[u8], iv: ~[u8], data: ~[u8]) -> ~[u8] {
let c = crypter(t);
c.init(encryptmode, key, iv);
let r = c.update(data);
let rest = c.final();
ret r + rest;
}
#[doc = "
Decrypts data, using the specified crypter type in decrypt mode with the
specified key and iv; returns the resulting (decrypted) data.
"]
fn decrypt(t: cryptertype, key: ~[u8], iv: ~[u8], data: ~[u8]) -> ~[u8] {
let c = crypter(t);
c.init(decryptmode, key, iv);
let r = c.update(data);
let rest = c.final();
ret r + rest;
}
#[cfg(test)]
mod tests {
// Test vectors from FIPS-197:
// http://csrc.nist.gov/publications/fips/fips197/fips-197.pdf
#[test]
fn test_aes_256_ecb() {
let k0 =
~[ 0x00u8, 0x01u8, 0x02u8, 0x03u8, 0x04u8, 0x05u8, 0x06u8, 0x07u8,
0x08u8, 0x09u8, 0x0au8, 0x0bu8, 0x0cu8, 0x0du8, 0x0eu8, 0x0fu8,
0x10u8, 0x11u8, 0x12u8, 0x13u8, 0x14u8, 0x15u8, 0x16u8, 0x17u8,
0x18u8, 0x19u8, 0x1au8, 0x1bu8, 0x1cu8, 0x1du8, 0x1eu8, 0x1fu8 ];
let p0 =
~[ 0x00u8, 0x11u8, 0x22u8, 0x33u8, 0x44u8, 0x55u8, 0x66u8, 0x77u8,
0x88u8, 0x99u8, 0xaau8, 0xbbu8, 0xccu8, 0xddu8, 0xeeu8, 0xffu8 ];
let c0 =
~[ 0x8eu8, 0xa2u8, 0xb7u8, 0xcau8, 0x51u8, 0x67u8, 0x45u8, 0xbfu8,
0xeau8, 0xfcu8, 0x49u8, 0x90u8, 0x4bu8, 0x49u8, 0x60u8, 0x89u8 ];
let c = crypter(aes_256_ecb);
c.init(encryptmode, k0, ~[]);
c.pad(false);
let r0 = c.update(p0) + c.final();
assert(r0 == c0);
c.init(decryptmode, k0, ~[]);
c.pad(false);
let p1 = c.update(r0) + c.final();
assert(p1 == p0);
}
}
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