Copyright	(c) 2025 Jared Tobin
License	MIT
Maintainer	Jared Tobin <jared@ppad.tech>
Safe Haskell	None
Language	Haskell2010

Crypto.MAC.Poly1305

Contents

Poly1305 message authentication code

Description

A pure Poly1305 MAC implementation, as specified by RFC 8439.

Synopsis

newtype MAC = MAC ByteString
mac :: ByteString -> ByteString -> Maybe MAC

Poly1305 message authentication code

newtype MAC Source #

A Poly1305 message authentication code.

Note that you should compare MACs for equality using the Eq instance, which performs the comparison in constant time, instead of unwrapping and comparing the underlying ByteStrings.

>>> let Just foo@(MAC bs0) = mac key "hi"
>>> let Just bar@(MAC bs1) = mac key "there"
>>> foo == bar -- do this
False
>>> bs0 == bs1 -- don't do this
False

Constructors

MAC ByteString

Instances

Instances details

Show MAC Source #
Instance details Defined in Crypto.MAC.Poly1305 Methods showsPrec :: Int -> MAC -> ShowS # show :: MAC -> String # showList :: [MAC] -> ShowS #
Eq MAC Source #
Instance details Defined in Crypto.MAC.Poly1305 Methods (==) :: MAC -> MAC -> Bool # (/=) :: MAC -> MAC -> Bool #

mac Source #

Arguments

:: ByteString	256-bit one-time key
-> ByteString	arbitrary-length message
-> Maybe MAC	128-bit message authentication code

Produce a Poly1305 MAC for the provided message, given the provided key.

Per RFC8439: the key, which is essentially a one-time key, should be unique, and MUST be unpredictable for each invocation.

The key must be exactly 256 bits in length.

>>> mac "i'll never use this key again!!!" "a message needing authentication"
Just "O'\231Z\224\149\148\246\203[}\210\203\b\200\207"