AES-CCM解密：Python正常运行但PHP实现失败求助

我需要解密智能设备获取的文本，Python中使用cryptography库的AESCCM可以正常解密，但PHP调用openssl_decrypt返回空结果，无任何错误提示，openssl_error_string()也无输出。环境支持AES-CCM（修改后的示例可运行），但设备返回的13字节nonce无法修改。

Python 可运行代码 #

from __future__ import annotations

import binascii
import base64

from cryptography.hazmat.primitives.ciphers.aead import AESCCM

def decrypt_payload(
    payload: bytes, mic: bytes, key: bytes, nonce: bytes
) -> dict[str, float] | None:
    cipher = AESCCM(key, tag_length=4)
    try:
        data = cipher.decrypt(nonce, payload + mic, None)
        print("Decryption succeeded, decrypted data:", data.hex())
    except ValueError as error:
        print()
        print("Decryption failed:", error)
        return None

# =============================
# main()
# =============================
def main() -> None:
    payload = bytes(bytearray.fromhex("73ad3f07fe89"))
    mic = bytes(bytearray.fromhex("d8c82d06"))
    key = bytes(bytearray.fromhex("D77B34645356FB1333BAD6357B38CCCF"))
    nonce = bytes(bytearray.fromhex("7cc6b66242d3e3fc4512ac1267"))
    decrypt_payload(payload=payload, mic=mic, key=key, nonce=nonce)

if __name__ == "__main__":
    main()

PHP 无法运行代码 #

<?php
$cipher = 'aes-256-ccm';
$payload = hex2bin("73ad3f07fe89");
$mic = hex2bin("d8c82d06");
$key = hex2bin("D77B34645356FB1333BAD6357B38CCCF");
$nonce = hex2bin("7cc6b66242d3e3fc4512ac1267");
if (in_array($cipher, openssl_get_cipher_methods())){
    $decrypted = openssl_decrypt($payload, $cipher, $key, OPENSSL_RAW_DATA, $nonce, $mic);
    echo "Error: " . openssl_error_string();
    echo $decrypted;
}
?>

解决提示 #

• 检查OpenSSL对CCM nonce长度的默认限制：执行echo openssl_cipher_iv_length('aes-256-ccm');，如果返回12，说明PHP的OpenSSL默认期望12字节nonce，而你的13字节nonce不符合默认要求，这是空返回的核心原因。

• 调整openssl_decrypt参数：显式传递空附加数据（AAD）并禁用填充，尝试修改调用代码：

$decrypted = openssl_decrypt(
    $payload,
    $cipher,
    $key,
    OPENSSL_RAW_DATA | OPENSSL_NO_PADDING,
    $nonce,
    $mic,
    '' // 空AAD，对应Python中的None参数
);

• 使用第三方加密库phpseclib：如果OpenSSL的限制无法绕过，phpseclib对CCM模式的参数支持更灵活，可直接指定13字节nonce和4字节tag长度。示例代码（需先通过Composer安装phpseclib/phpseclib）：

<?php
require 'vendor/autoload.php';

use phpseclib3\Crypt\AES;

$payload = hex2bin("73ad3f07fe89");
$mic = hex2bin("d8c82d06");
$key = hex2bin("D77B34645356FB1333BAD6357B38CCCF");
$nonce = hex2bin("7cc6b66242d3e3fc4512ac1267");

$aes = new AES('ccm');
$aes->setKey($key);
$aes->setNonce($nonce);
$aes->setTag($mic);
$aes->disablePadding();

$decrypted = $aes->decrypt($payload);
echo bin2hex($decrypted); // 应输出Python中解密成功的结果
?>

• 确认版本兼容性：确保PHP版本≥7.1，OpenSSL版本≥1.1.0，这些版本对CCM模式的非默认参数支持更完善。

内容的提问来源于stack exchange，提问作者Simon Wick