PHP: Class for encryption / decryption

PHP: Class for encryption / decryption

1. class Encryption {
2.  
3. const CYPHER = MCRYPT_RIJNDAEL_256;
4. const MODE = MCRYPT_MODE_CBC;
5. const KEY = 'anysecretkey';
6.  
7. public function encrypt($plaintext) {
8. $td = mcrypt_module_open(self::CYPHER, '', self::MODE, '');
9. $iv = mcrypt_create_iv(mcrypt_enc_get_iv_size($td), MCRYPT_RAND);
10. mcrypt_generic_init($td, self::KEY, $iv);
11. $crypttext = mcrypt_generic($td, $plaintext);
12. mcrypt_generic_deinit($td);
13. return base64_encode($iv . $crypttext);
14. }
15.  
16. public function decrypt($crypttext) {
17. $crypttext = base64_decode($crypttext);
18. $plaintext = '';
19. $td = mcrypt_module_open(self::CYPHER, '', self::MODE, '');
20. $ivsize = mcrypt_enc_get_iv_size($td);
21. $iv = substr($crypttext, 0, $ivsize);
22. $crypttext = substr($crypttext, $ivsize);
23. if ($iv) {
24. mcrypt_generic_init($td, self::KEY, $iv);
25. $plaintext = mdecrypt_generic($td, $crypttext);
26. }
27. return trim($plaintext);
28. }
29.  
30. }
31.  
32. // Using example:
33. // $encrypted_string = Encryption::encrypt('2');
34. // $decrypted_string = Encryption::decrypt($encrypted_string);
35. ?>