How do I encrypt a string in PHP?
encryption, php
Solution
Security Warning: Encryption without authentication is vulnerable to something called a chosen-ciphertext attack. See Eugene's answer for a solution that offers authenticated encryption.
If you are using PHP >= 5.3, the new `openssl_encrypt` might help you: It allows encryption of data using a wide range of cypher methods.
Those data can later be decrypted with `openssl_decrypt`, which, obviously, does the exact opposite.
And if you want to know which cypher functions you can use, `openssl_get_cipher_methods` will be helpful ;-) There are quite a lot of those, it seems ^^
Here's a portion of code I posted on my blog some time ago, that should demonstrate the usage of those three functions:
$methods = openssl_get_cipher_methods();
var_dump($methods);
$textToEncrypt = "he who doesn't do anything, doesn't go wrong -- Zeev Suraski";
$secretKey = "glop";
echo '<pre>';
foreach ($methods as $method) {
$encrypted = openssl_encrypt($textToEncrypt, $method, $secretKey);
$decrypted = openssl_decrypt($encrypted, $method, $secretKey);
echo $method . ': ' . $encrypted . ' ; ' . $decrypted . "\n";
}
echo '</pre>';
The output I got when writing this was something like that:
bf-ecb: /nyRYCzQPE1sunxSBclxXBd7p7gl1fUnE80gBCS1NM4s3wS1Eho6rFHOOR73V9UtnolYW+flbiCwIKa/DYh5CQ== ; he who doesn't do anything, doesn't go wrong -- Zeev Suraski
bf-ofb: M9wwf140zhwHo98k8sj2MEXdogqXEQ+TjN81pebs2tmhNOsfU3jvMy91MBM76dWM7GVjeh95p8oDybDt ; he who doesn't do anything, doesn't go wrong -- Zeev Suraski
cast5-cbc: xKgdC1y654PFYW1rIjdevu8MsQOegvJoZx0KmMwb8aCHFmznxIQVy1yvAWR3bZztvGCGrM84WkpbG33pZcxUiQ== ; he who doesn't do anything, doesn't go wrong -- Zeev Suraski
cast5-cfb: t8ABR9mPvocRikrX0Kblq2rUXHiVnA/OnjR/mDJDq8+/nn6Z9yfPbpcpRat0lYqfVAcwlypT4A4KNq4S ; he who doesn't do anything, doesn't go wrong -- Zeev Suraski
cast5-ecb: xKgdC1y654NIzRl9gJqbhYKtmJoXBoFpgLhwgdtPtYB7VZ1tRHLX0MjErtfREMJBAonp48zngSiTKlsKV0/WhQ== ; he who doesn't do anything, doesn't go wrong -- Zeev Suraski
cast5-ofb: t8ABR9mPvofCv9+AKTcRO4Q0doYlavn8zRzLvV3dZk0niO7l20KloA4nUll4VN1B5n89T/IuGh9piPte ; he who doesn't do anything, doesn't go wrong -- Zeev Suraski
des-cbc: WrCiOVPU1ipF+0trwXyVZ/6cxiNVft+TK2+vAP0E57b9smf9x/cZlQQ4531aDX778S3YJeP/5/YulADXoHT/+Q== ; he who doesn't do anything, doesn't go wrong -- Zeev Suraski
des-cfb: cDDlaifQN+hGOnGJ2xvGna7y8+qRxwQG+1DJBwQm/4abKgdZYUczC4+aOPGesZM1nKXjgoqB4+KTxGNo ; he who doesn't do anything, doesn't go wrong -- Zeev Suraski
And if you are not using PHP 5.3, you might want to take a look to the Mcrypt section of the manual, and functions such as `mcrypt_encrypt` ;-)
This is an interface to the mcrypt library, which supports a wide variety of block algorithms such as DES, TripleDES, Blowfish (default), 3-WAY, SAFER-SK64, SAFER-SK128, TWOFISH, TEA, RC2 and GOST in CBC, OFB, CFB and ECB cipher modes.
Problem
I want to make an encryption function that should have some secret key. Something like the following: ``` function encrypt($string) { $key = "mastermind"; $enc = encryptfunc($string, $key); return $enc; } ``` The same thing should apply for decryption.