mcrypt 问题

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<?php
/* Open the cipher */
$td = mcrypt_module_open('rijndael-256', '', 'ofb', '');

/* Create the IV and determine the keysize length, use MCRYPT_RAND
* on Windows instead */
$iv = mcrypt_create_iv(mcrypt_enc_get_iv_size($td), MCRYPT_DEV_RANDOM);
$ks = mcrypt_enc_get_key_size($td);

/* Create key */
$key = substr(md5('very secret key'), 0, $ks);

/* Intialize encryption */
mcrypt_generic_init($td, $key, $iv);

/* Encrypt data */
$encrypted = mcrypt_generic($td, 'This is very important data');
echo (base64_encode($encrypted));

?>

像这样,每次生成的encrypted都不一样. 那怎么能下次再解密?

encrypted

key

create

1 replies • 2014-07-30 03:26:06 +08:00

vixvix

Jul 30, 2014

你把mdecrypt_generic的文档和例子看看. 我没用过这个库，理论上来说，你只要用相同模块rijndael-256，和相同的key - 'very secret key'就可以解开加密的文件。加密的data由于使用random生成initialization vector(iv), 所以生成的加密数据每次也不同，具体细节可以参考使用的加密模块，例如这里用到的rijndael-256.