A concise PHP reversible cryptographic function (share) _php Tutorial

Many times we need to encrypt and decrypt data, such as some data that needs to be saved to a cookie, but not easily accessible by the user, and we need to encrypt the data to be stored in a cookie, and then decrypt it when we need to use it.

The encryption process is as follows:
Copy the Code code as follows:
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));
}

Re-decrypt when used:
if (Isset ($_cookie[' data '))
{
//Use a cookie to assign a value to the session
$_session[' data ' = Decrypt ("Nowamagic", $_cookie[' data ');
}

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));
}

The use of this reversible cryptographic function is recorded here.

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