php写的AES加密解密类分享

时间:2022-10-25 17:10:35

今天写了一个php的AES加密类。适用于Yii的扩展。
如果不用在Yii框架中,把代码中Yii::app()->params['encryptKey'] 换成你对应的默认key就可以了。
类代码:

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<?php
/**
 * php AES加解密类
 * 如果要与java共用,则密钥长度应该为16位长度
 * 因为java只支持128位加密,所以php也用128位加密,可以与java互转。
 * 同时AES的标准也是128位。只是RIJNDAEL算法可以支持128,192和256位加密。
 * java 要使用AES/CBC/NoPadding标准来加解密
 *
 * @author Terry
 *
 */
class PhpAes
{
    /**
     * This was AES-128 / CBC / NoPadding encrypted.
     * return base64_encode string
     * @author Terry
     * @param string $plaintext
     * @param string $key
     */
    public static function AesEncrypt($plaintext,$key = null)
    {
        $plaintext = trim($plaintext);
        if ($plaintext == '') return '';
        if(!extension_loaded('mcrypt'))
            throw new CException(Yii::t('yii','AesEncrypt requires PHP mcrypt extension to be loaded in order to use data encryption feature.'));
        $size = mcrypt_get_block_size(MCRYPT_RIJNDAEL_128, MCRYPT_MODE_CBC);
        $module = mcrypt_module_open(MCRYPT_RIJNDAEL_128, '', MCRYPT_MODE_CBC, '');
        $key=self::substr($key===null ? Yii::app()->params['encryptKey'] : $key, 0, mcrypt_enc_get_key_size($module));
        /* Create the IV and determine the keysize length, use MCRYPT_RAND
         * on Windows instead */
        $iv = substr(md5($key),0,mcrypt_enc_get_iv_size($module));
        /* Intialize encryption */
        mcrypt_generic_init($module, $key, $iv);
 
        /* Encrypt data */
        $encrypted = mcrypt_generic($module, $plaintext);
 
        /* Terminate encryption handler */
        mcrypt_generic_deinit($module);
        mcrypt_module_close($module);
        return base64_encode($encrypted);
    }
 
    /**
     * This was AES-128 / CBC / NoPadding decrypted.
     * @author Terry
     * @param string $encrypted     base64_encode encrypted string
     * @param string $key
     * @throws CException
     * @return string
     */
    public static function AesDecrypt($encrypted, $key = null)
    {
        if ($encrypted == '') return '';
        if(!extension_loaded('mcrypt'))
            throw new CException(Yii::t('yii','AesDecrypt requires PHP mcrypt extension to be loaded in order to use data encryption feature.'));
 
        $ciphertext_dec = base64_decode($encrypted);
        $module = mcrypt_module_open(MCRYPT_RIJNDAEL_128, '', MCRYPT_MODE_CBC, '');
        $key=self::substr($key===null ? Yii::app()->params['encryptKey'] : $key, 0, mcrypt_enc_get_key_size($module));
 
        $iv = substr(md5($key),0,mcrypt_enc_get_iv_size($module));
 
        /* Initialize encryption module for decryption */
        mcrypt_generic_init($module, $key, $iv);
 
        /* Decrypt encrypted string */
        $decrypted = mdecrypt_generic($module, $ciphertext_dec);
 
        /* Terminate decryption handle and close module */
        mcrypt_generic_deinit($module);
        mcrypt_module_close($module);
        return rtrim($decrypted,"\0");
    }
 
    /**
     * Returns the length of the given string.
     * If available uses the multibyte string function mb_strlen.
     * @param string $string the string being measured for length
     * @return integer the length of the string
     */
    private static function strlen($string)
    {
        return extension_loaded('mbstring') ? mb_strlen($string,'8bit') : strlen($string);
    }
 
    /**
     * Returns the portion of string specified by the start and length parameters.
     * If available uses the multibyte string function mb_substr
     * @param string $string the input string. Must be one character or longer.
     * @param integer $start the starting position
     * @param integer $length the desired portion length
     * @return string the extracted part of string, or FALSE on failure or an empty string.
     */
    private static function substr($string,$start,$length)
    {
        return extension_loaded('mbstring') ? mb_substr($string,$start,$length,'8bit') : substr($string,$start,$length);
    }
}