A case of PHP reversible cryptographic function code

Encrypt the data and write it into a cookie. $cookie _data = $this, Encrypt ("Nowamagic", $data); $cookie = Array ( ' Name ' = ' $data ', ' Value ' = $cookie _data, ' Expire ' = $user _expire, ' Domain ' = ', ' Path ' = '/', ' prefix ' and ' = ' ); $this->input->set_cookie ($cookie); Encryption Public function Encrypt ($key, $plain _text) { $plain _text = Trim ($plain _text); $IV = substr (MD5 ($key), 0,mcrypt_get_iv_size (MCRYPT_CAST_256,MCRYPT_MODE_CFB)); $c _t = MCRYPT_CFB (mcrypt_cast_256, $key, $plain _text, Mcrypt_encrypt, $IV); Return Trim (Chop (Base64_encode ($c _t)); }//edit bbs.it-home.org 2013/6/7 Decrypt if (Isset ($_cookie[' data ')) { Assign a value to a session with a cookie $_session[' data ' = Decrypt ("Nowamagic", $_cookie[' data '); } Resolving functions function Decrypt ($key, $c _t) { $c _t = Trim (Chop (Base64_decode ($c _t)); $IV = substr (MD5 ($key), 0,mcrypt_get_iv_size (MCRYPT_CAST_256,MCRYPT_MODE_CFB)); $p _t = MCRYPT_CFB (mcrypt_cast_256, $key, $c _t, Mcrypt_decrypt, $IV); Return Trim (Chop ($p _t)); } ?> Copy Code

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