我想要创建一个加密函数，需要一个秘密密钥。就像下面这样：
function encrypt($string) {
$key = "mastermind";
$enc = encryptfunc($string, $key);
return $enc;
}
如何在PHP中对字符串进行加密？
21
- John
1
2除非你真的知道自己在做什么（或者是在学习/实验），否则最好不要自己编写安全/加密函数。 - Matthew
5个回答
34
这是一个简单但安全的实现使用PBKDF2从明文密码创建加密密钥，并使用HMAC对加密消息进行身份验证的CBC模式下AES-256加密代码。
它适用于PHP 5.3及更高版本。
/**
* Implements AES-256 encryption/decryption in CBC mode.
*
* PBKDF2 is used for creation of encryption key.
* HMAC is used to authenticate the encrypted message.
*
* Requires PHP 5.3 and higher
*
* Gist: https://gist.github.com/eugef/3d44b2e0a8a891432c65
*/
class McryptCipher
{
const PBKDF2_HASH_ALGORITHM = 'SHA256';
const PBKDF2_ITERATIONS = 64000;
const PBKDF2_SALT_BYTE_SIZE = 32;
// 32 is the maximum supported key size for the MCRYPT_RIJNDAEL_128
const PBKDF2_HASH_BYTE_SIZE = 32;
/**
* @var string
*/
private $password;
/**
* @var string
*/
private $secureEncryptionKey;
/**
* @var string
*/
private $secureHMACKey;
/**
* @var string
*/
private $pbkdf2Salt;
public function __construct($password)
{
$this->password = $password;
}
/**
* Compares two strings.
*
* This method implements a constant-time algorithm to compare strings.
* Regardless of the used implementation, it will leak length information.
*
* @param string $knownHash The string of known length to compare against
* @param string $userHash The string that the user can control
*
* @return bool true if the two strings are the same, false otherwise
*
* @see https://github.com/symfony/security-core/blob/master/Util/StringUtils.php
*/
private function equalHashes($knownHash, $userHash)
{
if (function_exists('hash_equals')) {
return hash_equals($knownHash, $userHash);
}
$knownLen = strlen($knownHash);
$userLen = strlen($userHash);
if ($userLen !== $knownLen) {
return false;
}
$result = 0;
for ($i = 0; $i < $knownLen; $i++) {
$result |= (ord($knownHash[$i]) ^ ord($userHash[$i]));
}
// They are only identical strings if $result is exactly 0...
return 0 === $result;
}
/**
* PBKDF2 key derivation function as defined by RSA's PKCS #5: https://www.ietf.org/rfc/rfc2898.txt
*
* Test vectors can be found here: https://www.ietf.org/rfc/rfc6070.txt
* This implementation of PBKDF2 was originally created by https://defuse.ca
* With improvements by http://www.variations-of-shadow.com
*
* @param string $algorithm The hash algorithm to use. Recommended: SHA256
* @param string $password The password
* @param string $salt A salt that is unique to the password
* @param int $count Iteration count. Higher is better, but slower. Recommended: At least 1000
* @param int $key_length The length of the derived key in bytes
* @param bool $raw_output If true, the key is returned in raw binary format. Hex encoded otherwise
* @return string A $key_length-byte key derived from the password and salt
*
* @see https://defuse.ca/php-pbkdf2.htm
*/
private function pbkdf2($algorithm, $password, $salt, $count, $key_length, $raw_output = false)
{
$algorithm = strtolower($algorithm);
if (!in_array($algorithm, hash_algos(), true)) {
trigger_error('PBKDF2 ERROR: Invalid hash algorithm.', E_USER_ERROR);
}
if ($count <= 0 || $key_length <= 0) {
trigger_error('PBKDF2 ERROR: Invalid parameters.', E_USER_ERROR);
}
if (function_exists('hash_pbkdf2')) {
// The output length is in NIBBLES (4-bits) if $raw_output is false!
if (!$raw_output) {
$key_length *= 2;
}
return hash_pbkdf2($algorithm, $password, $salt, $count, $key_length, $raw_output);
}
$hash_length = strlen(hash($algorithm, '', true));
$block_count = ceil($key_length / $hash_length);
$output = '';
for ($i = 1; $i <= $block_count; $i++) {
// $i encoded as 4 bytes, big endian.
$last = $salt . pack('N', $i);
// first iteration
$last = $xorsum = hash_hmac($algorithm, $last, $password, true);
// perform the other $count - 1 iterations
for ($j = 1; $j < $count; $j++) {
$xorsum ^= ($last = hash_hmac($algorithm, $last, $password, true));
}
$output .= $xorsum;
}
if ($raw_output) {
return substr($output, 0, $key_length);
} else {
return bin2hex(substr($output, 0, $key_length));
}
}
/**
* Creates secure PBKDF2 derivatives out of the password.
*
* @param null $pbkdf2Salt
*/
private function derivateSecureKeys($pbkdf2Salt = null)
{
if ($pbkdf2Salt) {
$this->pbkdf2Salt = $pbkdf2Salt;
}
else {
$this->pbkdf2Salt = mcrypt_create_iv(self::PBKDF2_SALT_BYTE_SIZE, MCRYPT_DEV_URANDOM);
}
list($this->secureEncryptionKey, $this->secureHMACKey) = str_split(
$this->pbkdf2(self::PBKDF2_HASH_ALGORITHM, $this->password, $this->pbkdf2Salt, self::PBKDF2_ITERATIONS, self::PBKDF2_HASH_BYTE_SIZE * 2, true),
self::PBKDF2_HASH_BYTE_SIZE
);
}
/**
* Calculates HMAC for the message.
*
* @param string $message
* @return string
*/
private function hmac($message)
{
return hash_hmac(self::PBKDF2_HASH_ALGORITHM, $message, $this->secureHMACKey, true);
}
/**
* Encrypts the input text
*
* @param string $input
* @return string Format: hmac:pbkdf2Salt:iv:encryptedText
*/
public function encrypt($input)
{
$this->derivateSecureKeys();
$mcryptIvSize = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_128, MCRYPT_MODE_CBC);
// By default mcrypt_create_iv() function uses /dev/random as a source of random values.
// If server has low entropy this source could be very slow.
// That is why here /dev/urandom is used.
$iv = mcrypt_create_iv($mcryptIvSize, MCRYPT_DEV_URANDOM);
$encrypted = mcrypt_encrypt(MCRYPT_RIJNDAEL_128, $this->secureEncryptionKey, $input, MCRYPT_MODE_CBC, $iv);
$hmac = $this->hmac($this->pbkdf2Salt . $iv . $encrypted);
return implode(':', array(
base64_encode($hmac),
base64_encode($this->pbkdf2Salt),
base64_encode($iv),
base64_encode($encrypted)
));
}
/**
* Decrypts the input text.
*
* @param string $input Format: hmac:pbkdf2Salt:iv:encryptedText
* @return string
*/
public function decrypt($input)
{
list($hmac, $pbkdf2Salt, $iv, $encrypted) = explode(':', $input);
$hmac = base64_decode($hmac);
$pbkdf2Salt = base64_decode($pbkdf2Salt);
$iv = base64_decode($iv);
$encrypted = base64_decode($encrypted);
$this->derivateSecureKeys($pbkdf2Salt);
$calculatedHmac = $this->hmac($pbkdf2Salt . $iv . $encrypted);
if (!$this->equalHashes($calculatedHmac, $hmac)) {
trigger_error('HMAC ERROR: Invalid HMAC.', E_USER_ERROR);
}
// mcrypt_decrypt() pads the *RETURN STRING* with nulls ('\0') to fill out to n * blocksize.
// rtrim() is used to delete them.
return rtrim(
mcrypt_decrypt(MCRYPT_RIJNDAEL_128, $this->secureEncryptionKey, $encrypted, MCRYPT_MODE_CBC, $iv),
"\0"
);
}
}
使用方法：
$c = new McryptCipher('secret key goes here');
$encrypted = $c->encrypt('secret message');
$decrypted = $c->decrypt($encrypted);
性能提示
默认情况下，mcrypt_create_iv() 函数使用 /dev/random 作为随机值的源。如果服务器熵值较低，则该源可能非常缓慢。这就是为什么使用 /dev/urandom。
这里有一个很好的解释它们之间的区别 http://www.onkarjoshi.com/blog/191/device-dev-random-vs-urandom/
因此，如果您不是将此加密用于关键事物（我希望您不会这样做），则可以使用 /dev/urandom 来提高加密性能，否则只需将 MCRYPT_DEV_URANDOM 替换为 MCRYPT_DEV_RANDOM。
重要安全更新＃1
感谢 @HerrK 指出使用简单哈希创建加密密钥不够安全-现在使用 PBKDF2 算法来进行加密 (了解更多关于 PBKDF2 的内容请点击http://en.wikipedia.org/wiki/PBKDF2)。
PBKDF2算法的实现来自于 https://defuse.ca/php-pbkdf2.htm。
重要安全更新＃2
感谢 @Scott 关注到加密消息应该被验证，现在使用HMAC来验证消息是否被更改。
- Eugene Fidelin
10
1这不是一个安全的实现，该密钥并非通过安全生成而仅仅是散列处理。您需要使用密钥派生函数，例如http://en.wikipedia.org/wiki/PBKDF2。 - Herr
另外，您需要保留盐和IV以进行解密。 - Herr
1顺便说一下，你的新代码看起来很漂亮，而且工作得很好 :) - Herr
2@Scott，感谢您指出这一点。我已经为加密文本添加了HMAC身份验证。 - Eugene Fidelin
显示剩余5条评论
24
安全警告：未验证的加密容易受到所谓的选择性密文攻击。请查看Eugene's answer，以获得提供身份验证的加密解决方案。
如果您使用的是PHP >= 5.3，新版
稍后可以使用
如果您想知道可以使用哪些密码函数，则
以下是我在博客上发布的一段代码，可以演示这三个函数的用法：
openssl_encrypt可能会帮助您：它允许使用各种密码方法对数据进行加密。稍后可以使用
openssl_decrypt解密这些数据，这显然是相反的过程。如果您想知道可以使用哪些密码函数，则
openssl_get_cipher_methods将非常有用;-)
好像有很多这样的函数^^以下是我在博客上发布的一段代码，可以演示这三个函数的用法：
$methods = openssl_get_cipher_methods();
var_dump($methods);
$textToEncrypt = "he who doesn't do anything, doesn't go wrong -- Zeev Suraski";
$secretKey = "glop";
echo '<pre>';
foreach ($methods as $method) {
$encrypted = openssl_encrypt($textToEncrypt, $method, $secretKey);
$decrypted = openssl_decrypt($encrypted, $method, $secretKey);
echo $method . ': ' . $encrypted . ' ; ' . $decrypted . "\n";
}
echo '</pre>';
我写这个时得到的输出大致是这样的：
bf-ecb: /nyRYCzQPE1sunxSBclxXBd7p7gl1fUnE80gBCS1NM4s3wS1Eho6rFHOOR73V9UtnolYW+flbiCwIKa/DYh5CQ== ; he who doesn't do anything, doesn't go wrong -- Zeev Suraski
bf-ofb: M9wwf140zhwHo98k8sj2MEXdogqXEQ+TjN81pebs2tmhNOsfU3jvMy91MBM76dWM7GVjeh95p8oDybDt ; he who doesn't do anything, doesn't go wrong -- Zeev Suraski
cast5-cbc: xKgdC1y654PFYW1rIjdevu8MsQOegvJoZx0KmMwb8aCHFmznxIQVy1yvAWR3bZztvGCGrM84WkpbG33pZcxUiQ== ; he who doesn't do anything, doesn't go wrong -- Zeev Suraski
cast5-cfb: t8ABR9mPvocRikrX0Kblq2rUXHiVnA/OnjR/mDJDq8+/nn6Z9yfPbpcpRat0lYqfVAcwlypT4A4KNq4S ; he who doesn't do anything, doesn't go wrong -- Zeev Suraski
cast5-ecb: xKgdC1y654NIzRl9gJqbhYKtmJoXBoFpgLhwgdtPtYB7VZ1tRHLX0MjErtfREMJBAonp48zngSiTKlsKV0/WhQ== ; he who doesn't do anything, doesn't go wrong -- Zeev Suraski
cast5-ofb: t8ABR9mPvofCv9+AKTcRO4Q0doYlavn8zRzLvV3dZk0niO7l20KloA4nUll4VN1B5n89T/IuGh9piPte ; he who doesn't do anything, doesn't go wrong -- Zeev Suraski
des-cbc: WrCiOVPU1ipF+0trwXyVZ/6cxiNVft+TK2+vAP0E57b9smf9x/cZlQQ4531aDX778S3YJeP/5/YulADXoHT/+Q== ; he who doesn't do anything, doesn't go wrong -- Zeev Suraski
des-cfb: cDDlaifQN+hGOnGJ2xvGna7y8+qRxwQG+1DJBwQm/4abKgdZYUczC4+aOPGesZM1nKXjgoqB4+KTxGNo ; he who doesn't do anything, doesn't go wrong -- Zeev Suraski
如果您没有使用PHP 5.3，您可能需要查看手册中的Mcrypt部分以及类似mcrypt_encrypt的函数；-）
这是对mcrypt库的一个接口，它支持多种块算法，如DES、TripleDES、Blowfish（默认）、3-WAY、SAFER-SK64、SAFER-SK128、TWOFISH、TEA、RC2和GOST等，在CBC、OFB、CFB和ECB密码模式下。
- Pascal MARTIN
4
那个函数非常好用，如果我想使用AES256，我应该使用openssl_encrypt($texteACrypter, "AES265", $clefSecrete)吗？ - John
1php 5.4.20：我收到了“警告：openssl_encrypt（）：使用空的初始化向量（iv）可能是不安全的，不建议使用”。 - cenk
几乎使用了这个例子，但cenk是正确的，这是非常不安全的。要了解原因，请查看：https://dev59.com/U2gt5IYBdhLWcg3wxAVj - user3586062
请对您的密文进行MAC并在恒定时间内进行比较。 :) - Scott Arciszewski
5
虽然我不是加密专家，但我会使用这种工具：
function crypt($dataToEncrypt){
$appKey = '%39d15#13P0£df458asdc%/dfr_A!8792*dskjfzaesdfpopdfo45s4dqd8d4fsd+dfd4s"Z1';
$td = mcrypt_module_open(MCRYPT_SERPENT, '', MCRYPT_MODE_CBC, '');
// Creates IV and gets key size
$iv = mcrypt_create_iv(mcrypt_enc_get_iv_size($td), MCRYPT_DEV_RANDOM);
$ks = mcrypt_enc_get_key_size($td);
// Creates key from application key
$key = substr($appKey, 0, $ks);
// Initialization
mcrypt_generic_init($td, $key, $iv);
// Crypt data
$encrypted = mcrypt_generic($td, $dataToEncrypt);
// Close
mcrypt_generic_deinit($td);
mcrypt_module_close($td);
return array($encrypted, $iv);
}
为了解密一个字符串，你需要密钥和初始化向量 (
$iv)。function decrypt($encryptedData, $iv){
$appKey = '%39d15#13P0£df458asdc%/dfr_A!8792*dskjfzaesdfpopdfo45s4dqd8d4fsd+dfd4s"Z1';
$td = mcrypt_module_open(MCRYPT_SERPENT, '', MCRYPT_MODE_CBC, '');
// Gets key size
$ks = mcrypt_enc_get_key_size($td);
// Creates key from application key
$key = substr($appKey, 0, $ks);
// Initialization
mcrypt_generic_init($td, $key, $iv);
// Decrypt data
$decrypted = mdecrypt_generic($td, $encryptedData);
// Close
mcrypt_generic_deinit($td);
mcrypt_module_close($td);
return trim($decrypted);
}
- Arkh
1
41不，那只是我将头在键盘上滚动时创建的随机字符串。 - Arkh
3
这是对Eugene Fidelin原始代码的更新和加强版。
请注意输出结果中包含IV和Salt，您需要与解密密钥一起安全地存储它们。
请注意输出结果中包含IV和Salt，您需要与解密密钥一起安全地存储它们。
class Cipher
{
/**
----------------------------------------------
Original Code by Eugene Fidelin
----------------------------------------------
**/
private $key;
private $salt;
private $iv;
function __construct()
{
}
function set_salt( $salt )
{
$this->salt = $salt;
}
function generate_salt()
{
$this->salt = mcrypt_create_iv( 32, MCRYPT_DEV_RANDOM ); // abuse IV function for random salt
}
function set_iv( $iv )
{
$this->iv = $iv;
}
function generate_iv()
{
$this->iv = mcrypt_create_iv( mcrypt_get_iv_size( MCRYPT_RIJNDAEL_128, MCRYPT_MODE_CBC ) );
}
function generate_key( $passphrase, $iterations = 10000, $length = 32 )
{
$this->key = hash_pbkdf2 ( 'sha256', $passphrase, $this->salt, $iterations, $length );
}
function get_key()
{
echo $this->key;
}
function encrypt( $plaintext )
{
$ciphertext = mcrypt_encrypt( MCRYPT_RIJNDAEL_128, $this->key, $plaintext, MCRYPT_MODE_CBC, $this->iv );
$data_return = array();
$data_return['iv'] = base64_encode( $this->iv );
$data_return['salt'] = base64_encode( $this->salt );
$data_return['ciphertext'] = base64_encode( $ciphertext );
return json_encode( $data_return );
}
function decrypt( $data_enciphered, $passphrase )
{
$data_decoded = json_decode( $data_enciphered, TRUE );
$this->set_iv( base64_decode( $data_decoded['iv'] ) );
$this->set_salt( base64_decode( $data_decoded['salt'] ) );
$this->generate_key( $passphrase );
$ciphertext = base64_decode( $data_decoded['ciphertext'] );
return trim( mcrypt_decrypt( MCRYPT_RIJNDAEL_128, $this->key, $ciphertext, MCRYPT_MODE_CBC, $this->iv ) );
}
}
$cipher = new Cipher();
$cipher->generate_salt();
$cipher->generate_iv();
$cipher->generate_key( '123' ); // the key will be generated from the passphrase "123"
// echo $cipher->get_key();
$data_encrypted = $cipher->encrypt( 'hello' );
echo 'encrypted:';
echo '<pre>';
print_r( $data_encrypted );
echo '</pre>';
unset( $cipher );
echo 'decrypted:';
$cipher = new Cipher();
$decrypted = $cipher->decrypt( $data_encrypted, '123' );
echo '<pre>';
print_r( $decrypted );
echo '</pre>';
die();
- Herr
4
重要通知 - 盐和Iv不应该被安全地存储，您可以将其与加密文本一起传输。 - Eugene Fidelin
@massab 生成密钥() - Herr
@HerrK 我的意思是说 hash_pbkdf2 函数定义在哪里？ - Massab
@HerrK 我已经检查了我的服务器上的PHP版本是5.2.17，而这个函数在那个版本中没有被添加，有什么帮助吗？我该怎么办？ - Massab
1
这里有一个很好的PHP库，可以帮助您加密和解密字符串 - 可以通过Composer获取并且使用也很容易：
https://github.com/CoreProc/crypto-guard
这里是一个示例：<?php
require 'vendor/autoload.php';
use Coreproc\CryptoGuard\CryptoGuard;
// This passphrase should be consistent and will be used as your key to encrypt/decrypt
// your string
$passphrase = 'whatever-you-want';
// Instantiate the CryptoGuard class
$cryptoGuard = new CryptoGuard($passphrase);
$stringToEncrypt = 'test';
// This will spit out the encrypted text
$encryptedText = $cryptoGuard->encrypt($stringToEncrypt);
// This should give you back the string you encrypted
echo $cryptoGuard->decrypt($encryptedText);
- chrisbjr
网页内容由stack overflow 提供, 点击上面的可以查看英文原文，
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