note 107210 deleted from function.openssl-decrypt by salathe
| From: | salathe@php.net | Date: | Mon, 12 Jan 2015 20:10:00 +0000 |
| Subject: | note 107210 deleted from function.openssl-decrypt by salathe | ||
| References: | 1 | Groups: | php.notes |
| Request: | Send a blank email to php-notes+get-201416@lists.php.net to get a copy of this message | ||
Note Submitter: nbari at dalmp dot com
----
There are cases where you need to send data in a secure way within an 'un-secure'
connection, a typically scenario of this, is a site with out SSL (no https).
For this cases you can use the GibberishAES javascript library, this library will encrypt your data
before it is submitted using CBC AES encryption mode, and it is fully compatible with a standar like
OpenSSL.
Example:
When displaying a form, you can set a hidden field containing a token, the one is stored on the
server via sessions and is going to be used as the 'password' for encrypting the data on
the user side, in help with the GibberishAES library.
In Javascript (user side):
// GibberishAES.enc(string, password)
// Defaults to 256 bit encryption
GibberishAES.enc("Made with Gibberish\n", "password");
// Outputs: "U2FsdGVkX1+21O5RB08bavFTq7Yq/gChmXrO3f00tvJaT55A5pPvqw0zFVnHSW1o"
Later when the user submits the data, you will need to decrypt the data, for that you could use the
class below and use it like this:
<?php
sqAES::decrypt('password',
'U2FsdGVkX1+21O5RB08bavFTq7Yq/gChmXrO3f00tvJaT55A5pPvqw0zFVnHSW1o');
?>
That will return the same result, that openssl would return from this command line :
echo "U2FsdGVkX1+21O5RB08bavFTq7Yq/gChmXrO3f00tvJaT55A5pPvqw0zFVnHSW1o" | openssl enc -d
-aes-256-cbc -a -k password
This class currently only encrypts/decrypts AES256 but can be easily modified to feed your needs,
right now it is fully compatible withe the GibberishAES library, so you could decrypt all your
users data and also send encrypted data back to the user in a secure way, all this thanks to the
openssl-decrypt/openssl-encrypt functions.
<?php
class sqAES {
/**
* decrypt AES 256
*
* @param string $password
* @param data $edata
* @return dencrypted data
*/
public static function decrypt($password, $edata) {
$data = base64_decode($edata);
$salt = substr($data, 8, 8);
$ct = substr($data, 16);
/**
* From https://github.com/mdp/gibberish-aes
*
* Number of rounds depends on the size of the AES in use
* 3 rounds for 256
* 2 rounds for the key, 1 for the IV
* 2 rounds for 128
* 1 round for the key, 1 round for the IV
* 3 rounds for 192 since it's not evenly divided by 128 bits
*/
$rounds = 3;
$data00 = $password.$salt;
$md5_hash = array();
$md5_hash[0] = md5($data00, true);
$result = $md5_hash[0];
for ($i = 1; $i < $rounds; $i++) {
$md5_hash[$i] = md5($md5_hash[$i - 1].$data00, true);
$result .= $md5_hash[$i];
}
$key = substr($result, 0, 32);
$iv = substr($result, 32,16);
return openssl_decrypt($ct, 'aes-256-cbc', $key, true, $iv);
}
/**
* crypt AES 256
*
* @param string $password
* @param data $data
* @return base64 encrypted data
*/
public static function crypt($password, $data) {
// Set a random salt
$salt = openssl_random_pseudo_bytes(8);
$salted = '';
$dx = '';
// Salt the key(32) and iv(16) = 48
while (strlen($salted) < 48) {
$dx = md5($dx.$password.$salt, true);
$salted .= $dx;
}
$key = substr($salted, 0, 32);
$iv = substr($salted, 32,16);
$encrypted_data = openssl_encrypt($data, 'aes-256-cbc', $key, true, $iv);
return base64_encode('Salted__' . $salt . $encrypted_data);
}
}
?>