<?php
declare(strict_types=1);
namespace ParagonIE\HPKE\AEAD;
use ParagonIE\HPKE\HPKEException;
use ParagonIE\HPKE\Interfaces\AEADInterface;
use ParagonIE\HPKE\SymmetricKey;
use SodiumException;
class ChaCha20Poly1305 implements AEADInterface
{
const AEAD_ID = "\x00\x03";
public function getAeadId(): string
{
return self::AEAD_ID;
}
public function keyLength(): int
{
return 32;
}
public function nonceLength(): int
{
return 12;
}
public function tagLength(): int
{
return 16;
}
/**
* @throws SodiumException
*/
public function encrypt(
#[\SensitiveParameter] SymmetricKey $key,
#[\SensitiveParameter] string $plaintext,
string $nonce,
string $aad = ''
): array {
$output = sodium_crypto_aead_chacha20poly1305_ietf_encrypt(
$plaintext,
$aad,
$nonce,
$key->bytes
);
$ciphertext = substr($output, 0, -SODIUM_CRYPTO_AEAD_CHACHA20POLY1305_IETF_ABYTES);
$tag = substr($output, -SODIUM_CRYPTO_AEAD_CHACHA20POLY1305_IETF_ABYTES);
return [$ciphertext, $tag];
}
/**
* @throws HPKEException
* @throws SodiumException
*/
public function decrypt(
#[\SensitiveParameter] SymmetricKey $key,
string $ciphertext,
string $tag,
string $nonce,
string $aad = ''
): string {
$result = sodium_crypto_aead_chacha20poly1305_ietf_decrypt(
$ciphertext . $tag,
$aad,
$nonce,
$key->bytes
);
if (!is_string($result)) {
throw new HPKEException('Decryption error');
}
return $result;
}
}
|
Download
