php实现的rc4加密解密类定义与用法示例
发布:smiling 来源: PHP粉丝网 添加日期:2021-10-25 14:43:54 浏览: 评论:0
这篇文章主要介绍了php实现的rc4加密解密类定义与用法,结合完整实例形式给出了php rc4加密解密类文件class.rc4crypt.php的定义及相关使用技巧,需要的朋友可以参考下。
本文实例讲述了php实现的rc4加密解密类,分享给大家供大家参考,具体如下:
class.rc4crypt.php文件:
- <?php
- /*
- * By julying.com
- */
- define('CRYPT_RC4_MODE_INTERNAL', 1);
- define('CRYPT_RC4_MODE_MCRYPT', 2);
- define('CRYPT_RC4_ENCRYPT', 0);
- define('CRYPT_RC4_DECRYPT', 1);
- class Crypt_RC4 {
- /**
- * The Key
- *
- * @see Crypt_RC4::setKey()
- * @var String
- * @access private
- */
- var $key = "\0";
- /**
- * The Key Stream for encryption
- *
- * If CRYPT_RC4_MODE == CRYPT_RC4_MODE_MCRYPT, this will be equal to the mcrypt object
- *
- * @see Crypt_RC4::setKey()
- * @var Array
- * @access private
- */
- var $encryptStream = false;
- /**
- * The Key Stream for decryption
- *
- * If CRYPT_RC4_MODE == CRYPT_RC4_MODE_MCRYPT, this will be equal to the mcrypt object
- *
- * @see Crypt_RC4::setKey()
- * @var Array
- * @access private
- */
- var $decryptStream = false;
- /**
- * The $i and $j indexes for encryption
- *
- * @see Crypt_RC4::_crypt()
- * @var Integer
- * @access private
- */
- var $encryptIndex = 0;
- /**
- * The $i and $j indexes for decryption
- *
- * @see Crypt_RC4::_crypt()
- * @var Integer
- * @access private
- */
- var $decryptIndex = 0;
- /**
- * MCrypt parameters
- *
- * @see Crypt_RC4::setMCrypt()
- * @var Array
- * @access private
- */
- var $mcrypt = array('', '');
- /**
- * The Encryption Algorithm
- *
- * Only used if CRYPT_RC4_MODE == CRYPT_RC4_MODE_MCRYPT. Only possible values are MCRYPT_RC4 or MCRYPT_ARCFOUR.
- *
- * @see Crypt_RC4::Crypt_RC4()
- * @var Integer
- * @access private
- */
- var $mode;
- /**
- * Default Constructor.
- *
- * Determines whether or not the mcrypt extension should be used.
- *
- * @param optional Integer $mode
- * @return Crypt_RC4
- * @access public
- */
- var $continuousBuffer ;
- function Crypt_RC4()
- {
- if ( !defined('CRYPT_RC4_MODE') ) {
- switch (true) {
- case extension_loaded('mcrypt') && (defined('MCRYPT_ARCFOUR') || defined('MCRYPT_RC4')):
- // i'd check to see if rc4 was supported, by doing in_array('arcfour', mcrypt_list_algorithms('')),
- // but since that can be changed after the object has been created, there doesn't seem to be
- // a lot of point...
- define('CRYPT_RC4_MODE', CRYPT_RC4_MODE_MCRYPT);
- break;
- default:
- define('CRYPT_RC4_MODE', CRYPT_RC4_MODE_INTERNAL);
- }
- }
- switch ( CRYPT_RC4_MODE ) {
- case CRYPT_RC4_MODE_MCRYPT:
- switch (true) {
- case defined('MCRYPT_ARCFOUR'):
- $this->mode = MCRYPT_ARCFOUR;
- break;
- case defined('MCRYPT_RC4');
- $this->mode = MCRYPT_RC4;
- }
- }
- }
- /**
- * Sets the key.
- *
- * Keys can be between 1 and 256 bytes long. If they are longer then 256 bytes, the first 256 bytes will
- * be used. If no key is explicitly set, it'll be assumed to be a single null byte.
- *
- * @access public
- * @param String $key
- */
- function setKey($key)
- {
- $this->key = $key;
- if ( CRYPT_RC4_MODE == CRYPT_RC4_MODE_MCRYPT ) {
- return;
- }
- $keyLength = strlen($key);
- $keyStream = array();
- for ($i = 0; $i < 256; $i++) {
- $keyStream[$i] = $i;
- }
- $j = 0;
- for ($i = 0; $i < 256; $i++) {
- $j = ($j + $keyStream[$i] + ord($key[$i % $keyLength])) & 255;
- $temp = $keyStream[$i];
- $keyStream[$i] = $keyStream[$j];
- $keyStream[$j] = $temp;
- }
- $this->encryptIndex = $this->decryptIndex = array(0, 0);
- $this->encryptStream = $this->decryptStream = $keyStream;
- }
- /**
- * Dummy function.
- *
- * Some protocols, such as WEP, prepend an "initialization vector" to the key, effectively creating a new key [1].
- * If you need to use an initialization vector in this manner, feel free to prepend it to the key, yourself, before
- * calling setKey().
- *
- * [1] WEP's initialization vectors (IV's) are used in a somewhat insecure way. Since, in that protocol,
- * the IV's are relatively easy to predict, an attack described by
- * {@link http://www.drizzle.com/~aboba/IEEE/rc4_ksaproc.pdf Scott Fluhrer, Itsik Mantin, and Adi Shamir}
- * can be used to quickly guess at the rest of the key. The following links elaborate:
- *
- * {@link http://www.rsa.com/rsalabs/node.asp?id=2009 http://www.rsa.com/rsalabs/node.asp?id=2009}
- * {@link http://en.wikipedia.org/wiki/Related_key_attack http://en.wikipedia.org/wiki/Related_key_attack}
- *
- * @param String $iv
- * @see Crypt_RC4::setKey()
- * @access public
- */
- function setIV($iv)
- {
- }
- /**
- * Sets MCrypt parameters. (optional)
- *
- * If MCrypt is being used, empty strings will be used, unless otherwise specified.
- *
- * @link http://php.net/function.mcrypt-module-open#function.mcrypt-module-open
- * @access public
- * @param optional Integer $algorithm_directory
- * @param optional Integer $mode_directory
- */
- function setMCrypt($algorithm_directory = '', $mode_directory = '')
- {
- if ( CRYPT_RC4_MODE == CRYPT_RC4_MODE_MCRYPT ) {
- $this->mcrypt = array($algorithm_directory, $mode_directory);
- $this->_closeMCrypt();
- }
- }
- /**
- * Encrypts a message.
- *
- * @see Crypt_RC4::_crypt()
- * @access public
- * @param String $plaintext
- */
- function encrypt($plaintext)
- {
- return self::toHex($this->_crypt($plaintext, CRYPT_RC4_ENCRYPT));
- }
- /**
- * Decrypts a message.
- *
- * $this->decrypt($this->encrypt($plaintext)) == $this->encrypt($this->encrypt($plaintext)).
- * Atleast if the continuous buffer is disabled.
- *
- * @see Crypt_RC4::_crypt()
- * @access public
- * @param String $ciphertext
- */
- function decrypt($ciphertext)
- {
- $ciphertext = self::fromHex($ciphertext);
- return $this->_crypt($ciphertext, CRYPT_RC4_DECRYPT);
- }
- /**
- * Encrypts or decrypts a message.
- *
- * @see Crypt_RC4::encrypt()
- * @see Crypt_RC4::decrypt()
- * @access private
- * @param String $text
- * @param Integer $mode
- */
- function _crypt($text, $mode)
- {
- if ( CRYPT_RC4_MODE == CRYPT_RC4_MODE_MCRYPT ) {
- $keyStream = $mode == CRYPT_RC4_ENCRYPT ? 'encryptStream' : 'decryptStream';
- if ($this->$keyStream === false) {
- $this->$keyStream = mcrypt_module_open($this->mode, $this->mcrypt[0], MCRYPT_MODE_STREAM, $this->mcrypt[1]);
- mcrypt_generic_init($this->$keyStream, $this->key, '');
- } else if (!$this->continuousBuffer) {
- mcrypt_generic_init($this->$keyStream, $this->key, '');
- }
- $newText = mcrypt_generic($this->$keyStream, $text);
- if (!$this->continuousBuffer) {
- mcrypt_generic_deinit($this->$keyStream);
- }
- return $newText;
- }
- if ($this->encryptStream === false) {
- $this->setKey($this->key);
- }
- switch ($mode) {
- case CRYPT_RC4_ENCRYPT:
- $keyStream = $this->encryptStream;
- list($i, $j) = $this->encryptIndex;
- break;
- case CRYPT_RC4_DECRYPT:
- $keyStream = $this->decryptStream;
- list($i, $j) = $this->decryptIndex;
- }
- $newText = '';
- for ($k = 0; $k < strlen($text); $k++) {
- $i = ($i + 1) & 255;
- $j = ($j + $keyStream[$i]) & 255;
- $temp = $keyStream[$i];
- $keyStream[$i] = $keyStream[$j];
- $keyStream[$j] = $temp;
- $temp = $keyStream[($keyStream[$i] + $keyStream[$j]) & 255];
- $newText.= chr(ord($text[$k]) ^ $temp);
- }
- if ($this->continuousBuffer) {
- switch ($mode) {
- case CRYPT_RC4_ENCRYPT:
- $this->encryptStream = $keyStream;
- $this->encryptIndex = array($i, $j);
- break;
- case CRYPT_RC4_DECRYPT:
- $this->decryptStream = $keyStream;
- $this->decryptIndex = array($i, $j);
- }
- }
- return $newText;
- }
- /**
- * Treat consecutive "packets" as if they are a continuous buffer.
- *
- * Say you have a 16-byte plaintext $plaintext. Using the default behavior, the two following code snippets
- * will yield different outputs:
- *
- * <code>
- * echo $rc4->encrypt(substr($plaintext, 0, 8));
- * echo $rc4->encrypt(substr($plaintext, 8, 8));
- * </code>
- * <code>
- * echo $rc4->encrypt($plaintext);
- * </code>
- *
- * The solution is to enable the continuous buffer. Although this will resolve the above discrepancy, it creates
- * another, as demonstrated with the following:
- *
- * <code>
- * $rc4->encrypt(substr($plaintext, 0, 8));
- * echo $rc4->decrypt($des->encrypt(substr($plaintext, 8, 8)));
- * </code>
- * <code>
- * echo $rc4->decrypt($des->encrypt(substr($plaintext, 8, 8)));
- * </code>
- *
- * With the continuous buffer disabled, these would yield the same output. With it enabled, they yield different
- * outputs. The reason is due to the fact that the initialization vector's change after every encryption /
- * decryption round when the continuous buffer is enabled. When it's disabled, they remain constant.
- *
- * Put another way, when the continuous buffer is enabled, the state of the Crypt_DES() object changes after each
- * encryption / decryption round, whereas otherwise, it'd remain constant. For this reason, it's recommended that
- * continuous buffers not be used. They do offer better security and are, in fact, sometimes required (SSH uses them),
- * however, they are also less intuitive and more likely to cause you problems.
- *
- * @see Crypt_RC4::disableContinuousBuffer()
- * @access public
- */
- function enableContinuousBuffer()
- {
- $this->continuousBuffer = true;
- }
- /**
- * Treat consecutive packets as if they are a discontinuous buffer.
- *
- * The default behavior.
- *
- * @see Crypt_RC4::enableContinuousBuffer()
- * @access public
- */
- function disableContinuousBuffer()
- {
- if ( CRYPT_RC4_MODE == CRYPT_RC4_MODE_INTERNAL ) {
- $this->encryptIndex = $this->decryptIndex = array(0, 0);
- $this->setKey($this->key);
- }
- $this->continuousBuffer = false;
- }
- /**
- * Dummy function.
- *
- * Since RC4 is a stream cipher and not a block cipher, no padding is necessary. The only reason this function is
- * included is so that you can switch between a block cipher and a stream cipher transparently.
- *
- * @see Crypt_RC4::disablePadding()
- * @access public
- */
- function enablePadding()
- {
- }
- /**
- * Dummy function.
- *
- * @see Crypt_RC4::enablePadding()
- * @access public
- */
- function disablePadding()
- {
- }
- /**
- * Class destructor.
- *
- * Will be called, automatically, if you're using PHP5. If you're using PHP4, call it yourself. Only really
- * needs to be called if mcrypt is being used.
- *
- * @access public
- */
- function __destruct()
- {
- if ( CRYPT_RC4_MODE == CRYPT_RC4_MODE_MCRYPT ) {
- $this->_closeMCrypt();
- }
- }
- /**
- * Properly close the MCrypt objects.
- *
- * @access prviate
- */
- function _closeMCrypt()
- {
- if ( $this->encryptStream !== false ) {
- if ( $this->continuousBuffer ) {
- mcrypt_generic_deinit($this->encryptStream);
- }
- mcrypt_module_close($this->encryptStream);
- $this->encryptStream = false;
- }
- if ( $this->decryptStream !== false ) {
- if ( $this->continuousBuffer ) {
- mcrypt_generic_deinit($this->decryptStream);
- }
- mcrypt_module_close($this->decryptStream);
- $this->decryptStream = false;
- }
- }
- // @function fromHex 把十六进制数转换成字符串
- function toHex($sa , $len = 0){
- $buf = "";
- if( $len == 0 )
- $len = strlen($sa) ;
- for ($i = 0; $i < $len; $i++)
- {
- $val = dechex(ord($sa{$i}));
- if(strlen($val)< 2)
- $val = "0".$val;
- $buf .= $val;
- }
- return $buf;
- }
- // @function fromHex 把十六进制数转换成字符串
- function fromHex($sa){
- $buf = "";
- $len = strlen($sa) ;
- for($i = 0; $i < $len; $i += 2){
- $val = chr(hexdec(substr($sa, $i, 2)));
- $buf .= $val;
- }
- return $buf;
- }
- }
使用方法:
- include('class.rc4crypt.php');
- $rc4 = new Crypt_RC4();
- $rc4 -> setKey('21sd54a1w5q');
- $text = 'www.phpfensi.com';
- echo $x = $rc4->encrypt($text);//加密
- echo '<br />';
- echo $rc4->decrypt( $x) ;//解密
运行结果:
7907bb7c6694f179e9642ebd
www.phpfensi.com
Tags: rc4加密解密类
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