secretstream-stream


> Abstract encoding API of libsodium crypto_secretstream

Someday there will be a stream interface here too

Usage

``js
var secretstream = require('secretstream-stream')

// Parameters
var header = Buffer.alloc(secretstream.HEADERBYTES)
var key = secretstream.keygen()

// Init encryption side, writing into header Buffer, which needs to be shared
// with decryption side
var tx = secretstream.encrypt(header, key)
var ciphertext = tx.encrypt(secretstream.TAG_MESSAGE, Buffer.from('Hello world!'))

// Setup the decrypt side
var rx = secretstream.decrypt(header, key)
var plaintext = rx.decrypt(ciphertext)

console.log(plaintext.equals(Buffer.from('Hello world!')), rx.decrypt.tag.equals(secretstream.TAG_MESSAGE))

tx.destroy()
rx.destroy()
`

API

$3

#### Buffer sizes

- secretstream.KEYBYTES - Key size
- secretstream.HEADERBYTES - Header size
- secretstream.ABYTES - MAC size added to every message

#### Tags

- secretstream.TAG_MESSAGE
- secretstream.TAG_PUSH
- secretstream.TAG_FINAL
- secretstream.TAG_REKEY

$3

Generate a new symmetric key for use with .encrypt and .decrypt. The key is
stored in a sodium Secure Buffer. You can also save a allocation by passing in
the key buffer, which must be at least .KEYBYTES bytes.

$3

Create an encrypt instance with key, writing into header. header needs to
be passed the the decryption side somehow.

$3

Encrypt Buffer plaintext with added tag using optional Buffer ad, and
write into Buffer ciphertext at offset. ad can be null if unused, while
ciphertext will be allocated if not given. offset defalts to 0.

$3

Calculate the required length for a ciphertext from plaintext Buffer.

$3

Number of bytes written into ciphertext at last call to tx.encrypt

$3

Destroys the internal state and zero all memory. Can only be called once,
you may never call encrypt after and sets .bytes to null.

$3

Create an decrypt instance with key, using header from encrypt.

$3

Decrypt Buffer ciphertext using optional Buffer ad, and
write into Buffer plaintext at offset. ad can be null if unused, while
plaintext will be allocated if not given. offset defalts to 0.

$3

Calculate the required length for a plaintext from ciphertext Buffer.

$3

Number of bytes written into plaintext at last call to rx.decrypt

$3

A tag Buffer for the tag from the last decrypted ciphertext. Should be
compared against one of the exported tags. Please review the libsodium
documentation
for how tags should be interpreted.

$3

Destroys the internal state and zero all memory. Can only be called once,
you may never call encrypt after and sets .bytes and .tag to null.

Install

`sh
npm install secretstream-stream
``

License

ISC