Safe Haskell | None |
---|---|

Language | Haskell2010 |

## Synopsis

- type PublicKey a = SizedByteArray CRYPTO_BOX_PUBLICKEYBYTES a
- toPublicKey :: ByteArrayAccess bytes => bytes -> Maybe (PublicKey bytes)
- type SecretKey a = SizedByteArray CRYPTO_BOX_SECRETKEYBYTES a
- toSecretKey :: ByteArrayAccess bytes => bytes -> Maybe (SecretKey bytes)
- keypair :: IO (PublicKey ByteString, SecretKey ScrubbedBytes)
- type Nonce a = SizedByteArray CRYPTO_BOX_NONCEBYTES a
- toNonce :: ByteArrayAccess ba => ba -> Maybe (Nonce ba)
- create :: (ByteArrayAccess pkBytes, ByteArrayAccess skBytes, ByteArrayAccess nonceBytes, ByteArrayAccess ptBytes, ByteArray ctBytes) => PublicKey pkBytes -> SecretKey skBytes -> Nonce nonceBytes -> ptBytes -> ctBytes
- open :: (ByteArrayAccess skBytes, ByteArrayAccess pkBytes, ByteArrayAccess nonceBytes, ByteArray ptBytes, ByteArrayAccess ctBytes) => SecretKey skBytes -> PublicKey pkBytes -> Nonce nonceBytes -> ctBytes -> Maybe ptBytes

# Documentation

type PublicKey a = SizedByteArray CRYPTO_BOX_PUBLICKEYBYTES a Source #

Public key that can be used for Box.

This type is parametrised by the actual data type that contains
bytes. This can be, for example, a `ByteString`

.

toPublicKey :: ByteArrayAccess bytes => bytes -> Maybe (PublicKey bytes) Source #

Convert bytes to a public key.

type SecretKey a = SizedByteArray CRYPTO_BOX_SECRETKEYBYTES a Source #

Secret key that can be used for Box.

This type is parametrised by the actual data type that contains
bytes. This can be, for example, a `ByteString`

, but, since this
is a secret key, it is better to use `ScrubbedBytes`

.

toSecretKey :: ByteArrayAccess bytes => bytes -> Maybe (SecretKey bytes) Source #

Convert bytes to a secret key.

keypair :: IO (PublicKey ByteString, SecretKey ScrubbedBytes) Source #

Generate a new `SecretKey`

together with its `PublicKey`

.

Note: this function is not thread-safe (since the underlying
C function is not thread-safe both in Sodium and in NaCl)!
Either make sure there are no concurrent calls or see
`Crypto.Sodium.Init`

in
crypto-sodium
to learn how to make this function thread-safe.

type Nonce a = SizedByteArray CRYPTO_BOX_NONCEBYTES a Source #

Nonce that can be used for Box.

This type is parametrised by the actual data type that contains
bytes. This can be, for example, a `ByteString`

.

toNonce :: ByteArrayAccess ba => ba -> Maybe (Nonce ba) Source #

Make a `Nonce`

from an arbitrary byte array.

This function returns `Just`

if and only if the byte array has
the right length to be used as a nonce with a Box.

:: (ByteArrayAccess pkBytes, ByteArrayAccess skBytes, ByteArrayAccess nonceBytes, ByteArrayAccess ptBytes, ByteArray ctBytes) | |

=> PublicKey pkBytes | Receiver’s public key |

-> SecretKey skBytes | Sender’s secret key |

-> Nonce nonceBytes | Nonce |

-> ptBytes | Plaintext message |

-> ctBytes |

Encrypt a message.

encrypted = Box.create pk sk nonce message

`pk`

is the receiver’s public key, used for encryption.`sk`

is the sender’s secret key, used for authentication.These are generated using

`keypair`

and are supposed to be exchanged in advance. Both parties need to know their own secret key and the other’s public key.`nonce`

is an extra noise that ensures that if you encrypt the same message with the same key multiple times, you will get different ciphertexts, which is required for semantic security. There are two standard ways of getting it:*Use a counter*. In this case you keep a counter of encrypted messages, which means that the nonce will be new for each new message.*Random*. You generate a random nonce every time you encrypt a message. Since the nonce is large enough, the chances of you using the same nonce twice are negligible. For useful helpers, see`Crypto.Sodium.Random`

, in crypto-sodium.

In either case, you need to be able to provide the same nonce when decrypting, so you should be able to recover it by computation (e.g. in the case of a counter) or you should store it alongside the encrypted data. The nonce is not secret, so it is perfectly ok to store it in plaintext.

`message`

is the data you are encrypting.

This function adds authentication data, so if anyone modifies the cyphertext,
`open`

will refuse to decrypt it.

:: (ByteArrayAccess skBytes, ByteArrayAccess pkBytes, ByteArrayAccess nonceBytes, ByteArray ptBytes, ByteArrayAccess ctBytes) | |

=> SecretKey skBytes | Receiver’s secret key |

-> PublicKey pkBytes | Sender’s public key |

-> Nonce nonceBytes | Nonce |

-> ctBytes | Encrypted message (cyphertext) |

-> Maybe ptBytes |

Decrypt a message.

decrypted = Box.open sk pk nonce encrypted

`sk`

is the receiver’s secret key, used for description.`pk`

is the sender’s public key, used for authentication.`nonce`

is the same that was used for encryption.`encrypted`

is the output of`create`

.

This function will return `Nothing`

if the encrypted message was tampered
with after it was encrypted.