如何在 PHP 中进行 AES256 解密？

Question

我有一段加密的文本需要解密。它使用 AES-256-CBC 加密。我有加密的文本、密钥和 iv。但是，无论我尝试什么，我似乎都无法让它发挥作用。

互联网建议 mcrypt 的 Rijndael 密码应该能够做到这一点，所以这就是我现在所拥有的：

function decrypt_data($data, $iv, $key) {
    $cypher = mcrypt_module_open(MCRYPT_RIJNDAEL_128, '', MCRYPT_MODE_CBC, '');

    // initialize encryption handle
    if (mcrypt_generic_init($cypher, $key, $iv) != -1) {
        // decrypt
        $decrypted = mdecrypt_generic($cypher, $data);

        // clean up
        mcrypt_generic_deinit($cypher);
        mcrypt_module_close($cypher);

        return $decrypted;
    }

    return false;
}

就目前而言，我收到 2 个警告，输出是乱码：

Warning: mcrypt_generic_init() [function.mcrypt-generic-init]: Key size too large; supplied length: 64, max: 32 in /var/www/includes/function.decrypt_data.php on line 8
Warning: mcrypt_generic_init() [function.mcrypt-generic-init]: Iv size incorrect; supplied length: 32, needed: 16 in /var/www/includes/function.decrypt_data.php on line 8

任何帮助将不胜感激。

Answer 1

我对这些东西不是很熟悉，但似乎尝试用MCRYPT_RIJNDAEL_256 代替MCRYPT_RIJNDAEL_128 显然是下一步...

编辑：你是对的——这不是你需要的。 MCRYPT_RIJNDAEL_128 实际上是正确的选择。根据您提供的链接，您的密钥和 IV 是应有的两倍：

// How do you do 256-bit AES encryption in PHP vs. 128-bit AES encryption???
// The answer is:  Give it a key that's 32 bytes long as opposed to 16 bytes long.
// For example:
$key256 = '12345678901234561234567890123456';
$key128 = '1234567890123456';

// Here's our 128-bit IV which is used for both 256-bit and 128-bit keys.
$iv =  '1234567890123456';

Answer 2

我给你发一个例子， 请检查代码，好的

$data_to_encrypt = "2~1~000024~0910~20130723092446~T~00002000~USD~F~375019001012120~0~0~00000000000~";
$key128 = "abcdef0123456789abcdef0123456789";
$iv = "0000000000000000";

$cc = $data_to_encrypt;
$key = $key128;
$iv =  $iv;
$length = strlen($cc);

$cipher = mcrypt_module_open(MCRYPT_RIJNDAEL_128,'','cbc','');

mcrypt_generic_init($cipher, $key, $iv);
$encrypted = base64_encode(mcrypt_generic($cipher,$cc));
mcrypt_generic_deinit($cipher);

mcrypt_generic_init($cipher, $key, $iv);
$decrypted = mdecrypt_generic($cipher,base64_decode($encrypted));
mcrypt_generic_deinit($cipher);

echo "encrypted: " . $encrypted;
echo "<br/>";
echo "length:".strlen($encrypted);
echo "<br/>";
echo "decrypted: " . substr($decrypted, 0, $length);