Copyright	(C) Hécate Moonlight
License	BSD-3-Clause
Maintainer	The Haskell Cryptography Group
Stability	Stable
Portability	GHC only
Safe Haskell	None
Language	Haskell2010

LibSodium.Bindings.CryptoAuth

Contents

Introduction
Usage
Functions
Constants

Description

Synopsis

cryptoAuth :: Ptr CUChar -> Ptr CUChar -> CULLong -> Ptr CUChar -> IO CInt
cryptoAuthVerify :: Ptr CUChar -> Ptr CUChar -> CULLong -> Ptr CUChar -> IO CInt
cryptoAuthKeygen :: Ptr CUChar -> IO ()
cryptoAuthKeyBytes :: CSize
cryptoAuthBytes :: CSize

Introduction

Compute an authentication tag for a message and a secret key, and verify that a given tag is valid for a given message and a key.

The function computing the tag is deterministic: the same (message, key) tuple will always produce the same output. However, even if the message is public, knowing the key is required in order to be able to compute a valid tag. Therefore, the key should remain confidential. The tag, however, can be public.

The operations of this module are backed by the HMAC-SHA512-256 algorithm.

Usage

A typical use case is:

A prepares a message, adds an authentication tag, sends it to B
A doesn't store the message
Later on, B sends the message and the authentication tag to A
A uses the authentication tag to verify that it created this message.

This operation does not encrypt the message. It only computes and verifies an authentication tag.

Functions

cryptoAuth Source #

Arguments

:: Ptr CUChar	Buffer that will hold the computed authenticated tag, of size `cryptoAuthBytes`
-> Ptr CUChar	Buffer that holds the input message
-> CULLong	Length of the message
-> Ptr CUChar	Buffer that holds the secret key of size `cryptoAuthKeyBytes`
-> IO CInt

Compute a tag for the provided message and key.

See: crypto_auth()

Since: 0.0.1.0

cryptoAuthVerify Source #

Arguments

:: Ptr CUChar	Buffer that holds the tag
-> Ptr CUChar	Buffer that holds the message
-> CULLong	Length of the message
-> Ptr CUChar	Buffer that holds the secret key of size `cryptoAuthKeyBytes`
-> IO CInt	Returns -1 if the verification fails, and 0 if it passes.

Verify that the tag is valid for the provided message and secret key.

See: crypto_auth_verify()

Since: 0.0.1.0

cryptoAuthKeygen Source #

Arguments

:: Ptr CUChar	Buffer that holds the secret key of size `cryptoAuthKeyBytes`
-> IO ()

Create a random secret key of size cryptoAuthKeyBytes

It is equivalent to calling randombytesBuf but improves code clarity and can prevent misuse by ensuring that the provided key length is always be correct.

See: crypto_auth_keygen()

Since: 0.0.1.0

Constants

cryptoAuthKeyBytes :: CSize Source #

Size of the secret key

See: crypto_auth_KEYBYTES

Since: 0.0.1.0

cryptoAuthBytes :: CSize Source #

Size of the tag

See: crypto_auth_BYTES

Since: 0.0.1.0