php 3des加密解密类程序代码

class Crypt3Des {
var $key;
function Crypt3Des($key){
$this->key = $key;
}

function encrypt($input){
$size = mcrypt_get_block_size(MCRYPT_3DES,'ecb');
$input = $this->pkcs5_pad($input, $size);
$key = str_pad($this->key,24,'0');
$td = mcrypt_module_open(MCRYPT_3DES, '', 'ecb', '');
$iv = @mcrypt_create_iv (mcrypt_enc_get_iv_size($td), MCRYPT_RAND);
@mcrypt_generic_init($td, $key, $iv);
$data = mcrypt_generic($td, $input);
mcrypt_generic_deinit($td);
mcrypt_module_close($td);
//$data = base64_encode($this->PaddingPKCS7($data));
$data = base64_encode($data);
return $data;
}

function decrypt($encrypted){
$encrypted = base64_decode($encrypted);
$key = str_pad($this->key,24,'0');
$td = mcrypt_module_open(MCRYPT_3DES,'','ecb','');
$iv = @mcrypt_create_iv(mcrypt_enc_get_iv_size($td),MCRYPT_RAND);
$ks = mcrypt_enc_get_key_size($td);
@mcrypt_generic_init($td, $key, $iv);
$decrypted = mdecrypt_generic($td, $encrypted);
mcrypt_generic_deinit($td);
mcrypt_module_close($td);
$y=$this->pkcs5_unpad($decrypted);
return $y;
}

function pkcs5_pad ($text, $blocksize) {
$pad = $blocksize - (strlen($text) % $blocksize);
return $text . str_repeat(chr($pad), $pad);
}

function pkcs5_unpad($text){
$pad = ord($text{strlen($text)-1});
if ($pad > strlen($text)) {
   return false;
}
if (strspn($text, chr($pad), strlen($text) - $pad) != $pad){
   return false;
}
return substr($text, 0, -1 * $pad);
}

function PaddingPKCS7($data) {
$block_size = mcrypt_get_block_size(MCRYPT_3DES, MCRYPT_MODE_CBC);
$padding_char = $block_size - (strlen($data) % $block_size);
$data .= str_repeat(chr($padding_char),$padding_char);
return $data;
}
}

用法:

$crypt = new Crypt3Des('密钥');
$a = '待加密字符串';
$code = $crypt->encrypt($a);//加密
echo $crypt->decrypt($code);//解密