leigh / aead-chacha20-poly1305
RFC 7539 ChaCha20/Poly1305 AEAD construction
0.2.1
2016-02-05 15:59 UTC
Requires
- php: >=7.0
- leigh/chacha20: ^0.2.0
- leigh/poly1305: ^0.2.0
Requires (Dev)
- phpunit/phpunit: ~5.0
This package is not auto-updated.
Last update: 2024-11-09 19:04:39 UTC
README
This library contains a pure PHP implementation of the RFC 7539 ChaCha20/Poly1305 AEAD construction.
Usage:
Remember that a nonce must not be used more than once for a particular key
The library contains both one-shot functions for small amounts of data, and methods for processing streams of information without consuming large amounts of memory.
One-shot functions
// Encrypt and produce a ciphertext and tag.
list($ciphertext, $tag) = \ChaCha20Poly1305\encrypt($key, $nonce, $aad, $plaintext);
// Decrypt and produce a plaintext, throw an exception if the tag is invalid.
$plaintext = \ChaCha20Poly1305\decrypt($key, $nonce, $aad, $plaintext, $tag);
// Verify without decryption, return true/false depending the tag being valid.
$valid = \ChaCha20Poly1305\verify($key, $nonce, $aad, $plaintext, $tag);
The Context
object maintains the current state of all of the moving parts so they can be used for streaming. A separate context is needed for each stream.
Stream methods
$cipher = new \ChaCha20Poly1305\Cipher;
$encCtx = $cipher->init($key, $nonce);
$cipher->aad($encCtx, $additionalData);
$cipher->aad($encCtx, $moreData);
$ciphertext = $cipher->encrypt($encCtx, $plaintext);
$ciphertext .= $cipher->encrypt($encCtx, $morePlaintext);
$tag = $cipher->finish($encCtx);
// Or
$cipher = new \ChaCha20Poly1305\Cipher;
$decCtx = $cipher->init($key, $nonce);
$cipher->aad($decCtx, $additionalData);
$cipher->aad($decCtx, $moreData);
// Could also $cipher->verify() to skip decryption overhead.
$plaintext = $cipher->decrypt($decCtx, $ciphertext);
$plaintext .= $cipher->decrypt($decCtx, $moreCiphertext);
try {
$cipher->finish($decCtx, $tag);
}
catch (\ChaCha20Poly1305\AuthenticationException $e) {
// Tag was not valid
}