加密过滤器

*mcrypt.**和 *mdecrypt.**使用 libmcrypt 提供了对称的加密和解密。这两组过滤器都支持 mcrypt 扩展库中相同的算法,格式为 mcrypt.ciphername,其中 ciphername是密码的名字,将被传递给 mcrypt_module_open。有以下五个过滤器参数可用:

参数是否必须默认值取值举例
mode可选cbccbc, cfb, ecb, nofb, ofb, stream
algorithms_dir可选ini_get('mcrypt.algorithms_dir')algorithms 模块的目录
modes_dir可选ini_get('mcrypt.modes_dir')modes 模块的目录
iv必须N/A典型为 8,16 或 32 字节的二进制数据。根据密码而定
key必须N/A典型为 8,16 或 32 字节的二进制数据。根据密码而定

示例 #1 用 3DES 将文件加密输出

<?php
$passphrase = 'My secret';

/* Turn a human readable passphrase
 * into a reproducable iv/key pair
 */
$iv = substr(md5('iv'.$passphrase, true), 0, 8);
$key = substr(md5('pass1'.$passphrase, true) .
               md5('pass2'.$passphrase, true), 0, 24);
$opts = array('iv'=>$iv, 'key'=>$key);

$fp = fopen('secert-file.enc', 'wb');
stream_filter_append($fp, 'mcrypt.tripledes', STREAM_FILTER_WRITE, $opts);
fwrite($fp, 'Secret secret secret data');
fclose($fp);
?>

示例 #2 读取加密的文件

<?php
$passphrase = 'My secret';

/* Turn a human readable passphrase
 * into a reproducable iv/key pair
 */
$iv = substr(md5('iv'.$passphrase, true), 0, 8);
$key = substr(md5('pass1'.$passphrase, true) .
               md5('pass2'.$passphrase, true), 0, 24);
$opts = array('iv'=>$iv, 'key'=>$key);

$fp = fopen('secert-file.enc', 'rb');
stream_filter_append($fp, 'mdecrypt.tripledes', STREAM_FILTER_WRITE, $opts);
$data = rtrim(stream_get_contents($fp));
fclose($fp);

echo $data;
?>