用户注册的密码一般不会明文保存，总得加个密先。最简单的当然是在数据库sql语句中调用md5函数加密用户密码。这里介绍一个加解密类。如果你想在用户忘记密码时为他或她找回原来的密码，那么这个类是个好用的工具。当然，这个加解密类也可用于其他用途。
代码如下:
PHPclass crypt { private $skey; public function __construct($key) {
$this->skey = hash("md5",$key,true); //32位skey
} public function safe_b64encode($string) {
$data = base64_encode($string);
$data = str_replace(array('+','/','='),array('-','_',''),$data);
return $data;
} public function safe_b64decode($string) {
$data = str_replace(array('-','_'),array('+','/'),$string);
$mod4 = strlen($data) % 4;
if ($mod4) {
$data .= substr('====',$mod4);
}
return base64_decode($data);
} public function encode($value) {
if (!$value) {
return false;
}
$text = $value;
$iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256,MCRYPT_MODE_ECB);
$iv = mcrypt_create_iv($iv_size,MCRYPT_RAND);
$crypttext = mcrypt_encrypt(MCRYPT_RIJNDAEL_256,$this->skey,$text,MCRYPT_MODE_ECB,$iv);
return trim($this->safe_b64encode($crypttext));
} public function decode($value) {
if (!$value) {
return false;
}
$crypttext = $this->safe_b64decode($value);
$iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256,MCRYPT_RAND);
$decrypttext = mcrypt_decrypt(MCRYPT_RIJNDAEL_256,$crypttext,$iv);
return trim($decrypttext);
}}
$this->skey = hash("md5",$key,true); //32位skey
} public function safe_b64encode($string) {
$data = base64_encode($string);
$data = str_replace(array('+','/','='),array('-','_',''),$data);
return $data;
} public function safe_b64decode($string) {
$data = str_replace(array('-','_'),array('+','/'),$string);
$mod4 = strlen($data) % 4;
if ($mod4) {
$data .= substr('====',$mod4);
}
return base64_decode($data);
} public function encode($value) {
if (!$value) {
return false;
}
$text = $value;
$iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256,MCRYPT_MODE_ECB);
$iv = mcrypt_create_iv($iv_size,MCRYPT_RAND);
$crypttext = mcrypt_encrypt(MCRYPT_RIJNDAEL_256,$this->skey,$text,MCRYPT_MODE_ECB,$iv);
return trim($this->safe_b64encode($crypttext));
} public function decode($value) {
if (!$value) {
return false;
}
$crypttext = $this->safe_b64decode($value);
$iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256,MCRYPT_RAND);
$decrypttext = mcrypt_decrypt(MCRYPT_RIJNDAEL_256,$crypttext,$iv);
return trim($decrypttext);
}}
