nettle-0.2.0: safe nettle binding

Copyright(c) 2013 Stefan Bühler
LicenseMIT-style (see the file COPYING)
Maintainerstbuehler@web.de
Stabilityexperimental
Portabilityportable
Safe HaskellNone
LanguageHaskell98

Crypto.Nettle.UMAC

Description

This module exports the UMAC algorithms supported by nettle: http://www.lysator.liu.se/~nisse/nettle/

Synopsis

Documentation

class UMAC u where #

UMAC is a class of keyed hash algorithms that take an additional nonce.

Keys for UMAC are always 16 bytes; there are different digest sizes: 4, 8, 12 and 16 bytes (32, 64, 96 and 128 bits), and the variants are named after the digest length in bits.

On initialization the nonce is set to 0; each finalize returns a new state with an incremented nonce. The nonce is interpreted as 16-byte (128-bit) big-endian integer (and for string shorter than 16 bytes padded with zeroes on the left; setting empty nonces is not allowed).

Methods

umacDigestSize :: Tagged u Int #

digest size in bytes

umacName :: Tagged u String #

umac name (UMAC ++ digest size in bits)

umacInit :: ByteString -> u #

initialize a new context from a key with a zero nonce

umacSetNonce :: u -> ByteString -> u #

set a nonce; can be called anytime before producing the digest

umacUpdate :: u -> ByteString -> u #

append message data to be hashed

umacUpdateLazy :: u -> ByteString -> u #

append lazy message data to be hashed

umacFinalize :: u -> (ByteString, u) #

produce a digest, and return a new state with incremented nonce

umacInitKeyedHash #

Arguments

:: (UMAC u, KeyedHashAlgorithm u) 
=> ByteString

key argument

-> ByteString

nonce argument

-> Tagged u KeyedHash 

The default KeyedHash generated for UMAC KeyedHashAlgorithm instances use a zero nonce; to set a different nonce you need to use this initialization function (or use the UMAC interface).

Once the UMAC lives as KeyedHash the nonce cannot be changed anymore, as KeyedHash hides all internal state.