<?php
$algo = 'aes-256-gcm';
$iv = random_bytes(openssl_cipher_iv_length($algo));
$key = random_bytes(32); // 256 bit
//$data = random_bytes(1024); // 1 Kb of random data
$data = "well hello there";
$ciphertext = openssl_encrypt(
$data,
$algo,
$key,
OPENSSL_RAW_DATA,
$iv,
$tag
);
// Change 1 bit in ciphertext
// $i = rand(0, mb_strlen($ciphertext, '8bit') - 1);
// $ciphertext[$i] = $ciphertext[$i] ^ chr(1);
echo(base64_encode($ciphertext));
echo("\n");
echo(base64_encode($tag));
$i = rand(0, mb_strlen($tag, '8bit') - 1);
$tag[$i] = $tag[$i] ^ chr(1);
echo("\n");
echo(base64_encode($tag));
$decrypt = openssl_decrypt(
$ciphertext,
$algo,
$key,
OPENSSL_RAW_DATA,
$iv,
$tag
);
if (false === $decrypt) {
throw new Exception(sprintf(
"OpenSSL error: %s", openssl_error_string()
));
}
printf ("Decryption %s\n", $data === $decrypt ? 'Ok' : 'Failed');
preferences:
28.31 ms | 402 KiB | 5 Q