I want to encrypt a message by php but at client side, I want javascript to decrypt it. I had tried Blowfish(using mcrypt ), but I discovered that php echoing non-alpha-numberic character and Javascript display alpha-numeric. I am using ajax so that the page will not reload.
I had tested codes from http://aam.ugpl.de/?q=node/1060 and http://www.php-einfach.de/blowfish_en.php#ausgabe.
Any help is appreciated.
Edit: I use Diffie-Hellman to calculate secret key with random generated number a and b. Below is the resulted from php code
class Encryption
{
const CYPHER = 'blowfish';
const MODE = 'cbc';
const KEY = '26854571066639171754759502724211797107457520821';
public function encrypt($plaintext)
{
$td = mcrypt_module_open(self::CYPHER, '', self::MODE, '');
$iv = mcrypt_create_iv(mcrypt_enc_get_iv_size($td), MCRYPT_RAND);
mcrypt_generic_init($td, self::KEY, $iv);
$crypttext = mcrypt_generic($td, $plaintext);
mcrypt_generic_deinit($td);
return $iv.$crypttext;
}
public function decrypt($crypttext)
{
$plaintext = '';
$td = mcrypt_module_open(self::CYPHER, '', self::MODE, '');
$ivsize = mcrypt_enc_get_iv_size($td);
$iv = substr($crypttext, 0, $ivsize);
$crypttext = substr($crypttext, $ivsize);
if ($iv)
{
mcrypt_generic_init($td, self::KEY, $iv);
$plaintext = mdecrypt_generic($td, $crypttext);
}
return $plaintext;
}
}
$encrypted_string = Encryption::encrypt('this is a test');
$decrypted_string = Encryption::decrypt($encrypted_string);
echo "encrypted: $encrypted_string<br>";
echo "decrypted: $decrypted_string<br>";
encrypted: µ˜?r_¿ÖŸŒúw‰1‹Žn!úaH
decrypted: this is a test
This javascript AES crypto library from a few stanford students is the best I've seen:
http://crypto.stanford.edu/sjcl/
But note their caveat:
We believe that SJCL provides the best security which is practically available in Javascript. (Unfortunately, this is not as great as in desktop applications because it is not feasible to completely protect against code injection, malicious servers and side-channel attacks.)
UPDATE:
In PHP, use base64_encode() after encrypting and base64_decode() before decrypting. This way it will be rendered with characters safe for transmission. In the browser, use atob() and btoa().
Related
So my goal is to demonstrate an online version of the enigma machine. I'm using PHP to do this and using mcrypt as it seems to be the only way to use the enigma algorithm without writing it out myself.
Trouble is there is no information out there currently on how to set up mcrypt's enigma.
I am also using stream as nothing else seems to work before anyone asks.
I really would be greatful for any help regarding this.
This is my current setup.
$td = mcrypt_module_open('enigma', '', 'stream', '');
$iv = mcrypt_create_iv(mcrypt_enc_get_iv_size($td), MCRYPT_DEV_RANDOM);
$ks = mcrypt_enc_get_key_size($td);
$key = substr(md5('very secret key'), 0, $ks);
mcrypt_generic_init($td, $key, $iv);
$encrypted = mcrypt_generic($td, 'This is very important data');
mcrypt_generic_deinit($td);
mcrypt_generic_init($td, $key, $iv);
$decrypted = mdecrypt_generic($td, $encrypted);
mcrypt_generic_deinit($td);
mcrypt_module_close($td);
echo trim($decrypted) . "\n";
How do I get it encrypt in the enigma way then display it in ciphertext aswell as the ordinary text?
When running you're code I'm getting this warning:
Warning: mcrypt_create_iv(): Cannot create an IV with a size of less than 1 or greater than 2147483647
The error occurs because
mcrypt_enc_get_iv_size($td)
gives an value of '0':
$ivSize = mcrypt_enc_get_iv_size($td);
echo "ivSize: " . $ivSize;
ivSize: 0
The solution is to use a blank IV:
$iv = "";
and everything works like expected:
echo trim($decrypted) . "\n";
This is very important data
currently we have a mcrypt implentation on our systems to crypt some Ids in our PHP application.
But Mcrypt is deprecated now and I have to replace it.
Unfortunately, I cannot convert all of the saved information.
Decryption would be enough.
These are the two functions that I use:
self::$key = '123456';
public static function encrypt($plaintext)
{
$td = mcrypt_module_open('cast-256', '', 'ecb', '');
$iv = mcrypt_create_iv (mcrypt_enc_get_iv_size($td), MCRYPT_RAND);
mcrypt_generic_init($td, self::$key, $iv);
$encrypted_data = mcrypt_generic($td, $plaintext);
mcrypt_generic_deinit($td);
mcrypt_module_close($td);
$encoded_64 = base64_encode($encrypted_data);
return trim($encoded_64);
}
and
public static function decrypt($crypttext)
{
$decoded_64 = base64_decode($crypttext);
$td = mcrypt_module_open('cast-256', '', 'ecb', '');
$iv = mcrypt_create_iv (mcrypt_enc_get_iv_size($td), MCRYPT_RAND);
mcrypt_generic_init($td, self::$key, $iv);
$decrypted_data = mdecrypt_generic($td, $decoded_64);
mcrypt_generic_deinit($td);
mcrypt_module_close($td);
return trim($decrypted_data);
}
Eh? PHP has OpenSSL support ... https://www.php.net/manual/en/book.openssl.php
"So, certainly yes." You can use mcrypt to decrypt all of your existing information and then encrypt it using OpenSSL or some other cipher algorithm of your choosing.
Now, I'd bear in mind that OpenSSL is very much designed around the notion of "public and private keys." So, if you go that route, you should try to take advantage of that. There are actually a great many cipher algorithms that can be used in modern PHP ... https://www.php.net/manual/en/function.crypt.php
m using
public function encrypt($plain_str,$key)
{
$str= mcrypt_encrypt(MCRYPT_RIJNDAEL_128, $key, $plain_str, MCRYPT_MODE_ECB, mcrypt_create_iv(mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_ECB), MCRYPT_RAND));
$str = urlencode(base64_encode($str));
return $str ;
}
public function decrypt($cipher_str,$key)
{
$str = urldecode(base64_decode($cipher_str));
return mcrypt_decrypt(MCRYPT_RIJNDAEL_128, $key, $str, MCRYPT_MODE_ECB, mcrypt_create_iv(mcrypt_get_iv_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_ECB), MCRYPT_RAND));
}
on crypting :201433~58~g#fds.com~20140820142427
i get : %2BAihYMLwpwrsmL4lSGGzwFTfonvdCyOb%2BCGEUJ%2F%2BE%2F7ZnvgwFRYFtlazQeSrVjUjyaaGZADK8%2BZyynIGxyt4VQ%3D%3D
on decrypting : %2BAihYMLwpwrsmL4lSGGzwFTfonvdCyOb%2BCGEUJ%2F%2BE%2F7ZnvgwFRYFtlazQeSrVjUjyaaGZADK8%2BZyynIGxyt4VQ%3D%3D
i get :201433~58~g#fds.com~20140820142427 back but
when string is malformed like some character removed
like this : %2BAihYMLwpwrsmL4lSGGzwFTfonvdCyOb%2BCGEUJ%2F%2BE%2F7Z
on decrypting i get : 201433~58~g#fds.com~201408201424O#¿W«Gݽˋ¯ È#'oP´ŸØw\Â⦑
How can i detect this anomoly ?
First of all, I'd like to list some flaws in your code:
Don't use ECB mode.
You are encrypting using MCRYPT_RIJNDAEL_128, but you're getting the IV size for MCRYPT_RIJNDAEL_256. (btw, IV is ignored in ECB mode, which is one of the reasons why not to use it)
You are also using MCRYPT_RAND as your randomness source, which is not secure. You should use MCRYPT_DEV_URANDOM (that is also the new default in PHP 5.6).
You don't have to urlencode() the resulting ciphertext, Base64 encoding is URL-safe.
Now, to answer your question ... this is done via a HMAC. The easiest way to use a HMAC is to prepend the cipher-text with it (which you should do with the IV as well; don't worry, it's not a secret):
public function encrypt($plainText, $encKey, $hmacKey)
{
$ivSize = mcrypt_get_iv_size('rijndael-128', 'ctr');
$iv = mcrypt_create_iv($ivSize, MCRYPT_DEV_URANDOM);
$cipherText = mcrypt_encrypt('rijndael-128', $encKey, $plainText, 'ctr', $iv);
$cipherText = $iv.$cipherText;
$hmac = hash_hmac('sha256', $cipherText, $hmacKey, true);
return base64_encode($hmac.$cipherText);
}
public function decrypt($cipherText, $encKey, $hmacKey)
{
$cipherText = base64_decode($cipherText);
if (strlen($cipherText) <= 32)
{
throw new Exception('Authentication failed!');
}
$recvHmac = substr($cipherText, 0, 32);
$cipherText = substr($cipherText, 32);
$calcHmac = hash_hmac('sha256', $cipherText, $hmacKey, true);
if ( ! hash_equals($recvHmac, $calcHmac))
{
throw new Exception('Authentication failed!');
}
$ivSize = mcrypt_get_iv_size('rijndael-128', 'ctr');
$iv = substr($cipherText, $ivSize);
$cipherText = substr($cipherText, $ivSize);
return mcrypt_decrypt('rijndael-128', $encKey, $cipherText, 'ctr', $iv);
}
Please note that the encryption key and HMAC key are different - they most NOT be the same key. Also, for Rijndael-128, you should create a 128-bit (or 16-byte) random key, it is not something that you can just type in with your keyboard. Here's how to generate one:
$encKey = mcrypt_create_iv(16, MCRYPT_DEV_URANDOM);
I'm having a problem when writing and parsing some DATA out of stored cookies.
Here are my crypt and decrypt functions (which I have found in another topic here).
function decrypt($crypttext){
$crypttext = base64_decode($crypttext);
$plaintext = '';
$td = mcrypt_module_open(MCRYPT_RIJNDAEL_256, '', MCRYPT_MODE_CBC, '');
$ivsize = mcrypt_enc_get_iv_size($td);
$iv = substr($crypttext, 0, $ivsize);
$crypttext = substr($crypttext, $ivsize);
if ($iv)
{
mcrypt_generic_init($td, CRYPTKEY, $iv);
$plaintext = mdecrypt_generic($td, $crypttext);
}
return trim($plaintext);
}
function encrypt($plaintext){
$td = mcrypt_module_open(MCRYPT_RIJNDAEL_256, '', MCRYPT_MODE_CBC, '');
$iv = mcrypt_create_iv(mcrypt_enc_get_iv_size($td), MCRYPT_RAND);
mcrypt_generic_init($td, CRYPTKEY, $iv);
$crypttext = mcrypt_generic($td, $plaintext);
mcrypt_generic_deinit($td);
return base64_encode($iv.$crypttext);
}
My usage is fairly simple:
//read, split if neccesarry, check if already in it, if not-> add, crypt, write
if(isset($_COOKIE['DATA'])){
$data = decrypt($_COOKIE['DATA']);
$search = explode('#',$data);
if(!in_array($lnk, $search)){
$data.= "#".$lnk; // $lnk = additional data
$err = setrawcookie("DATA", encrypt($data));
}
$err = true;
}
In most tries, it doesn't work adding a $lnk. The decryption of the cookie after I've wrote it, is wrong. undefined junk. (so something doesn't work well).
I haven't been able to find any errors in the code at all. My best guess is that the problem is caused by :
$ivsize = mcrypt_enc_get_iv_size($td);
$iv = substr($crypttext, 0, $ivsize);
Specifically, that $ciphertext is smaller than $ivsize?
Any other ideas?
// to prevent questions about it:
the data which i store, are just php uniqueID()'s separeted by '#'. so maybe in future there will be 10 IDs stored (encrypted) in the cookie...i didin't know the max size of a cookie and the factor AES blow this up, but i thought a cookie should get it.
(if there is a easier synchronus way to encrypt (this should not be high security, but mostly safe) please feel free to tell me.
Try using bin2hex instead of base64_encode(). I previously answered a similar question on SO.
Ok, I have tried to create my own encryption/decryption methods using PHP mcrypt, and when I posted them a while back some called them "trash". They were mentioning things about "Initialization Vectors" and such. Basically, how can I make these cryptography methods better:
function encrypt($key, $data){
$encrypted_data = mcrypt_cbc(MCRYPT_RIJNDAEL_192, $key, $data, MCRYPT_ENCRYPT);
return base64_encode($encrypted_data);
}
function decrypt($key, $encryptedData){
$dec = base64_decode($encryptedData);
$decrypt = mcrypt_cbc(MCRYPT_RIJNDAEL_192, $key, $dec, MCRYPT_DECRYPT);
return trim($decrypt);
}
I want these to work the best they can except I am a duck in a brand new world when it comes to mcrypt, any suggestions are welcome, thanks!
Here is a snippet of the mcrypt functions I use. They use mcrypt_generic and mdecrypt_generic, which should be used according to the PHP manual.
function encrypt($key, $data){
$b = mcrypt_get_block_size(MCRYPT_RIJNDAEL_256, MCRYPT_MODE_CBC);
$enc = mcrypt_module_open(MCRYPT_RIJNDAEL_256, '', MCRYPT_MODE_CBC, '');
$iv = mcrypt_create_iv(mcrypt_enc_get_iv_size($enc), MCRYPT_DEV_URANDOM);
mcrypt_generic_init($enc, md5($key), $iv);
// PKCS7 Padding from: https://gist.github.com/1077723
$dataPad = $b-(strlen($data)%$b);
$data .= str_repeat(chr($dataPad), $dataPad);
$encrypted_data = mcrypt_generic($enc, $data);
mcrypt_generic_deinit($enc);
mcrypt_module_close($enc);
return array(
'data' => base64_encode($encrypted_data),
'iv' => base64_encode($iv)
);
}
function decrypt($key, $iv, $encryptedData){
$iv = base64_decode($iv);
$enc = mcrypt_module_open(MCRYPT_RIJNDAEL_256, '', MCRYPT_MODE_CBC, '');
mcrypt_generic_init($enc, md5($key), $iv);
$encryptedData = base64_decode($encryptedData);
$data = mdecrypt_generic($enc, $encryptedData);
mcrypt_generic_deinit($enc);
mcrypt_module_close($enc);
// PKCS7 Padding from: https://gist.github.com/1077723
$dataPad = ord($data[strlen($data)-1]);
return substr($data, 0, -$dataPad);
}
I don't know much about mcrypt either, so I just kinda hacked these together. I md5 the key so it's always 32 characters (the max key length), and I randomly calculate an "Initialization Vector".
Using PKCS7 Padding is better because you can have strings that end in white space (as trim would remove that), also the encryption is more efficient when the string is a certain length.
I'm using AES 256 (MCRYPT_RIJNDAEL_256) here, but AES 192 (MCRYPT_RIJNDAEL_192) would work too.
Demo: http://ideone.com/WA5Tk
You can create an iv with mcrypt_create_iv(), using the appropriate size for your encryption mode.
$size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_192, MCRYPT_MODE_CBC);
$iv = mcrypt_create_iv($size, MCRYPT_DEV_RANDOM);
Then pass it to mcrypt_cbc() as the optional 5th parameter. The only changes I've made here to your original functions are to pass in $iv:
function encrypt($key, $data, $iv){
$encrypted_data = mcrypt_cbc(MCRYPT_RIJNDAEL_192, $key, $data, MCRYPT_ENCRYPT, $iv);
return base64_encode($encrypted_data);
}
function decrypt($key, $encryptedData, $iv){
$dec = base64_decode($encryptedData);
$decrypt = mcrypt_cbc(MCRYPT_RIJNDAEL_192, $key, $dec, MCRYPT_DECRYPT, $iv);
return trim($decrypt);
}