Crypto.Threefish.Authenticated

Authenticated encryption using Skein for PRNG, KDF, stream cipher and MAC.

Documentation

data DecryptFailure

Constructors

BadMAC

NoDecode String

Instances

Show DecryptFailure

data Encrypted a

An encrypt-then-MACed value. The binary format is as follows: Bytes What 0-31 256 bit nonce 32-63 256 bit Skein-MAC 64-71 Length of cryptotext as a 64 bit little endian word. 71- Cryptotext

Instances

Show (Encrypted a)

Serialize (Encrypted a)

type Plaintext = ByteString

data Block256

Instances

Eq Block256

Show Block256

Serialize Block256

Skein Block256

Threefish Block256 Threefish256

type Nonce256 = Block256

type Key256 = Block256

encrypt :: Serialize a => Key256 -> a -> Encrypted a

Encrypt-then-MAC any serializable value. The 256 bit nonce is generated using a Skein-based PRNG seeded from the system's entropy pool. This means that two successive calls to encrypt will not yield the exact same output; however, the identity forall k, x. Right x == decrypt k (encrypt k x) will always hold.

The subkeys for encryption and MAC are generated by applying Skein-KDF to the master key, with the key identifiers crypt and mac respectively, zero padded at the end until 32 bytes.

decrypt :: Serialize a => Key256 -> Encrypted a -> Either DecryptFailure a

Decrypt and decode a message. Will fail if there is a MAC mismatch or if the message can't be decoded into the given data type.

encrypt' :: Key256 -> Nonce256 -> Plaintext -> Encrypted a

Encrypt-then-MAC a message given a key and a nonce. Note that using the same nonce more than once for a given key will completely destroy security.

decrypt' :: Key256 -> Encrypted a -> Either DecryptFailure Plaintext

Verify and decrypt a message.

encryptBytes :: Key256 -> ByteString -> ByteString

Encrypt-then-MAC a lazy ByteString.

decryptBytes :: Key256 -> ByteString -> Either DecryptFailure Plaintext

Verify and decrypt a lazy ByteString.

generateNonce :: IO Nonce256

Generate a 256 bit nonce using the Skein PRNG.

toBlock :: Threefish a b => ByteString -> Maybe a

Create an appropriately sized block.

fromBlock :: Threefish a b => a -> ByteString

Extract the contents of a block.