我在解密以 %3D%3D 结尾的值时遇到问题。解密后,我得到一个完全难以辨认的返回值。加密值是通过查询字符串传递的,但我已经运行了一个循环测试值 0 到 200,以排除 url 编码的问题。
加密解密函数:
function encryptValue($encrypt) {
$key = variable_get_local("privateKey", $default = "");
$iv = mcrypt_create_iv(mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_ECB), MCRYPT_RAND);
$passcrypt = trim(mcrypt_encrypt(MCRYPT_RIJNDAEL_256, $key, trim($encrypt), MCRYPT_MODE_ECB, $iv));
$encode = urlencode(base64_encode($passcrypt));
return $encode;
}
function decryptValue($decrypt) {
$key = variable_get_local("privateKey", $default = "");
$decoded = base64_decode(urldecode($decrypt));
$iv = mcrypt_create_iv(mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_ECB), MCRYPT_RAND);
$decrypted = trim(mcrypt_decrypt(MCRYPT_RIJNDAEL_256, $key, trim($decoded), MCRYPT_MODE_ECB, $iv));
return $decrypted;
}
我尝试在加密和解密过程中保持 iv 值相同,但这不会改变输出。我还尝试删除 trim($decoded)
周围的 trim()
但这也没有改变任何东西。
下面是我用来识别问题的方法。 0 到 200 之间的加密将产生 9 次以 %3D%3D 结尾的值,并导致解密失败。
for($i=0;$i<200;$i++) {
echo encryptValue($i) . "<br/>";
echo decryptValue(encryptValue($i)) . "<br/><hr/>";
}
感谢您的阅读。
最佳答案
以下是当前脚本中的一些观察结果:
- ECB 模式不安全,请使用
CBC
代替 MCRYPT_RAND
与rand
相同,请参阅 str_shuffle and randomness使用 MCRYPT_DEV_URANDOM 代替- 为了更好的安全性,使用加密+使用
HMAC
进行身份验证来防止oracle padding攻击 - 使用经过适当测试的库
Zend\Crypt
而不是创建您自己的库,因为您不是安全专家
示例:
// Encription Key
$encryptionKey = mcrypt_create_iv(16, MCRYPT_DEV_URANDOM); // Stored securely
// Signature Key
$signatureKey = mcrypt_create_iv(16, MCRYPT_DEV_URANDOM); // Stored securely
// Start DataEncryption Object
$obj = new DataEncryption($encryptionKey, $signatureKey);
$obj->setEncoding(DataEncryption::ENCODE_BASE64);
// Test
for($i = 0; $i < 200; $i ++) {
printf("%s = %s\n", $encode = $obj->encrypt($i), $obj->decrypt($encode));
}
输出
eSCknmsoMHY2oo5lpW3NpQhDigs4+Fw8aObeIhK+wPyUImQbvlh/aUrW = 0
qFswb3VO5+Foi4kjVn6s5lpZbiWgdKmfObh37/xjPyqB4ZFfAXNUeYYX = 1
WKG0BCKUxOXWU6S3YJ/dNL46Lcn7lt+ihG4tEoZuORDoJXSjz6Vrcepn = 2
K24QqkGYC86btzGQ5HKKMewVhiEIdKOajpgLx8SMKVKfCwlOJlbRwpaz = 3
0DbJycPZ24FOAhQrhQJmgMsP0p2nFzYUlFVOFlbQ8zhLTXkcdnNOhVfi = 4
l7saQG2BTPAZR2EnYjxfNmTxEBBaAh+n9+8eOCITDGzEVShw9wOxP7Pt = 5
eUhvvHJOFsy6ZaBu40XgU+N5VtuFBesRVx0ryfManIXva5y7J0ShiKcE = 6
TaX+172N60X1UTVmMWYcdcn7YzN7xoAOVEPpaD7r1pE3OtX5Erg4nja8 = 7
0LM3W0pkQ73IsmqAgRiQvqL0/rdkk7YvuwcVwoe1NI+qZo7Jq8gyFIvn = 8
....
38m8fEoUhoTyPPBukg3KVhrmwVDyVCcnWx/5erAslUDzEP7Bddzj5y8Y = 196
Dwi6t7sX30bxjbVXMKCWEZs0FxTUZM4IPHKR3VD6kygi7op0Q6ARCZJW = 197
TJ/faDaIuE0mDPHmGar1BeIyAnfVD0Z47ZtCcHjz5AZzaQ1YWH8kF1bU = 198
FYh+8Kts4ubVvTT5o0vZYfKC+8ExhpD5pWgHK3EhvGWkcPwKerSIvkK0 = 199
使用的类
class DataEncryption {
private $keyEncryption;
private $keySignature;
private $ivSize;
private $cipher = MCRYPT_RIJNDAEL_128;
private $mode = MCRYPT_MODE_CBC;
private $signatureLength = 10;
private $encoding = 2; // I prefer hex
const ENCODE_BASE64 = 1;
const ENCODE_HEX = 2;
function __construct($encryptionKey = null, $signatureKey = null) {
// Set Keys
$this->keyEncryption = empty($encryptionKey) ? mcrypt_create_iv(32, MCRYPT_DEV_URANDOM) : $encryptionKey;
$this->keySignature = empty($signatureKey) ? mcrypt_create_iv(32, MCRYPT_DEV_URANDOM) : $signatureKey;
// Get IV Size
$this->ivSize = mcrypt_get_iv_size($this->cipher, $this->mode);
}
public function getKeys() {
return array(
"encryption" => $this->keyEncryption,
"signature" => $this->keySignature
);
}
public function setMode($mode) {
$this->mode = $mode;
}
public function setCipher($cipher) {
$this->cipher = $cipher;
}
public function setEncoding($encode) {
$this->encoding = $encode;
}
public function encrypt($data) {
// add PKCS7 padding to data
$block = mcrypt_get_block_size($this->cipher, $this->mode);
$pad = $block - (strlen($data) % $block);
$data .= str_repeat(chr($pad), $pad);
$iv = $this->rand($this->ivSize);
$cipherData = mcrypt_encrypt($this->cipher, $this->keyEncryption, $data, $this->mode, $iv);
$finalData = $iv . $cipherData;
// protected against padding oracle attacks
$finalData = $this->sign($finalData) . $finalData;
return $this->encode($finalData);
}
public function decrypt($data) {
$data = $this->decode($data);
// Check Integrity
if (! $this->check($data)) {
return false;
}
$data = substr($data, $this->signatureLength);
// Break Data
$iv = substr($data, 0, $this->ivSize);
$cipherData = substr($data, $this->ivSize);
$data = mcrypt_decrypt($this->cipher, $this->keyEncryption, $cipherData, $this->mode, $iv);
// Remove PKCS7 padding
$block = mcrypt_get_block_size($this->cipher, $this->mode);
$pad = ord($data[($len = strlen($data)) - 1]);
// $data = rtrim($data, "\0..\32");
return substr($data, 0, $len - $pad);
}
public function encode($data) {
return $this->encoding === self::ENCODE_BASE64 ? base64_encode($data) : bin2hex($data);
}
public function decode($data) {
return $this->encoding === self::ENCODE_BASE64 ? base64_decode($data) : pack("H*", $data);
}
public function sign($data) {
$hash = hash_hmac('sha256', $data, $this->keySignature, true);
return substr($hash, 0, $this->signatureLength);
}
public function check($data) {
$signature = substr($data, 0, $this->signatureLength);
$data = substr($data, $this->signatureLength);
$hash = hash_hmac('sha256', $data, $this->keySignature, true);
// return $signature === substr($hash, 0, $this->signatureLength);
return $this->compare($signature, substr($hash, 0, $this->signatureLength));
}
public function rand($no) {
return mcrypt_create_iv($no, MCRYPT_DEV_URANDOM);
}
/**
* Prevent Timing Attacks
* @param string $a
* @param string $b
* @return boolean
*/
public function compare($a, $b) {
if (strlen($a) !== strlen($b)) {
return false;
}
$result = 0;
for($i = 0; $i < strlen($a); $i ++) {
$result |= ord($a[$i]) ^ ord($b[$i]);
}
return $result == 0;
}
}
关于PHP 使用trim() 对某些字符串解密失败,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/16518795/