Crypto.Saltine.Core.SecretBox

Secret-key authenticated encryption: Crypto.Saltine.Core.SecretBox

The secretbox function encrypts and authenticates a message ByteString using a secret key and a nonce. The secretboxOpen function verifies and decrypts a ciphertext ByteString using a secret key and a nonce. If the ciphertext fails validation, secretboxOpen returns Nothing.

The Crypto.Saltine.Core.SecretBox module is designed to meet the standard notions of privacy and authenticity for a secret-key authenticated-encryption scheme using nonces. For formal definitions see, e.g., Bellare and Namprempre, "Authenticated encryption: relations among notions and analysis of the generic composition paradigm," Lecture Notes in Computer Science 1976 (2000), 531–545, http://www-cse.ucsd.edu/~mihir/papers/oem.html.

Note that the length is not hidden. Note also that it is the caller's responsibility to ensure the uniqueness of nonces—for example, by using nonce 1 for the first message, nonce 2 for the second message, etc. Nonces are long enough that randomly generated nonces have negligible risk of collision.

Crypto.Saltine.Core.SecretBox is crypto_secretbox_xsalsa20poly1305, a particular combination of Salsa20 and Poly1305 specified in "Cryptography in NaCl" (http://nacl.cr.yp.to/valid.html). This function is conjectured to meet the standard notions of privacy and authenticity.

This is version 2010.08.30 of the secretbox.html web page.

Documentation

data Key

An opaque secretbox cryptographic key.

Instances

Eq Key

Methods

(==) :: Key -> Key -> Bool

(/=) :: Key -> Key -> Bool

Ord Key

Methods

compare :: Key -> Key -> Ordering

(<) :: Key -> Key -> Bool

(<=) :: Key -> Key -> Bool

(>) :: Key -> Key -> Bool

(>=) :: Key -> Key -> Bool

max :: Key -> Key -> Key

min :: Key -> Key -> Key

IsEncoding Key

Methods

encode :: Key -> ByteString

decode :: ByteString -> Maybe Key

encoded :: (Choice p, Applicative f) => p Key (f Key) -> p ByteString (f ByteString)

data Nonce

An opaque secretbox nonce.

Instances

Eq Nonce

Methods

(==) :: Nonce -> Nonce -> Bool

(/=) :: Nonce -> Nonce -> Bool

Ord Nonce

Methods

compare :: Nonce -> Nonce -> Ordering

(<) :: Nonce -> Nonce -> Bool

(<=) :: Nonce -> Nonce -> Bool

(>) :: Nonce -> Nonce -> Bool

(>=) :: Nonce -> Nonce -> Bool

max :: Nonce -> Nonce -> Nonce

min :: Nonce -> Nonce -> Nonce

IsNonce Nonce

Methods

zero :: Nonce

nudge :: Nonce -> Nonce

IsEncoding Nonce

Methods

encode :: Nonce -> ByteString

decode :: ByteString -> Maybe Nonce

encoded :: (Choice p, Applicative f) => p Nonce (f Nonce) -> p ByteString (f ByteString)

secretbox

Arguments

:: Key

-> Nonce

-> ByteString

Message

-> ByteString

Ciphertext

Encrypts a message. It is infeasible for an attacker to decrypt the message so long as the Nonce is never repeated.

secretboxOpen

Arguments

:: Key

-> Nonce

-> ByteString

Ciphertext

-> Maybe ByteString

Message

Decrypts a message. Returns Nothing if the keys and message do not match.

newKey :: IO Key

Creates a random key of the correct size for secretbox.

newNonce :: IO Nonce

Creates a random nonce of the correct size for secretbox.