For a practical example suitable for encrypting and
validating cookies or passing secure messages,
go to 

the encrypted result data maybe binary data and It make errors in sql
query.
so use the base64_encode/base64_decode function with mcrypt()
try below

base64_encode(mcrypt_ecb(MCRYPT_BLOWFISH,$key,$input,MCRYPT_ENCRYPT));

mcrypt_ecb(MCRYPT_BLOWFISH,$key,base64_decode($input),MCRYPT_DECRYPT);

If you are interested to see a blowfish implementation written in plain
php, go to 

I was just testing if it is possible. Yes it is, but it's really slow and
unoptimized yet :( Maybe somebody knows how to speed the code up ?

Bye
Bjoern

If you are trying to use mcrypt to encrypt and decrypt data for storing in
cookies, then you should use bin2hex() before storing the data. 
If you use rawurlencode() instead, then Internet Explorer does something
fishy with the cookie, and when you try and use mdecrypt on the cookie
later, the decrypt fails part way through.

Mcrypt support in PHP has gone through cycles and it seems to have finally
leveled off. 

First, get libmcrypt-2.4.15 (well, that was the lastest as of today) and
compile it. Pay no attention to the mcrypt examples in this manual as most
of them will simply cause your web server to segfault. Here are some
functions that I hope will help others with mcrypt. 

PHP Manual Editor : Can you remove all the outdated comments and examples
from the manual? It was seriously confusing to get to the bottom of the
problems I had starting to use mcrypt and it's fairly straight forward
now, I just think the PHP manual needs some updating in this area. Note
that it seems Zend's manual pages have been updated as that's where I
finally got some working example code.

Thanks!!!
 


$sCryptoKey = "whatever";

	function
	my_encrypt($sString) {
	
		GLOBAL $sCryptoKey;
		
		$iIV = mcrypt_create_iv (mcrypt_get_iv_size (MCRYPT_RIJNDAEL_256,
MCRYPT_MODE_ECB), MCRYPT_RAND);
		
		$sEncrypted = mcrypt_encrypt (MCRYPT_RIJNDAEL_256, $sCryptoKey,
$sString, MCRYPT_MODE_ECB, $iIV);
		
		return($sEncrypted);

	} // End function my_encrypt

	function
	my_decrypt($sString) {

		GLOBAL $sCryptoKey;
		
		$iIV = mcrypt_create_iv (mcrypt_get_iv_size (MCRYPT_RIJNDAEL_256,
MCRYPT_MODE_ECB), MCRYPT_RAND);
		
		$sDecrypted = mcrypt_decrypt(MCRYPT_RIJNDAEL_256, $sCryptoKey, $sString,
MCRYPT_MODE_ECB, $iIV);
	
		return(trim($sDecrypted));
			
	} // End function my_decrypt

According to the mcrypt manual page at 
, RC4 is not included with Mcrypt(as stated above). If anyone else is
looking for RC4, as I was, there is a PHP library at sourceforge.net
called RC4Crypt.

If you compiled mcrypt and php without problem, but phpinfo() shows there
are no supported ciphers and modes, try to change mode to 755 on libdirs
(/usr/local/libmcrypt, /usr/local/libcrypt).

The example2 contain this key:

$key = "this is a very secret key";

It's a 25 character length key and the max for TripleDES is 24
characters...

I had some problems trying to link mcrypt module with PhP 4.1.1.
After sometimes, I figured that the PhP configure command incorrectly adds
mcrypt library to the LIBS
//Original code
#LIBS="-lmcrypt
#      -L$MCRYPT_DIR/lib
#     $LIBS"

// modify like this:
LIBS=$LIBS" -lmcrypt"
LIBS=" -L$MCRYPT_DIR/lib
     $LIBS"

Hope this helps,
Leon

if you download 
you can use rc4 encryption with PHP 4.*.* on windows.


regester the dll by going to the directory and typing (regsvr32
rc4dll.dll) 

use


<?

$RC4 = new COM("RC4DLL.Crypt") or die("Unable to load
RC4"); 

echo "(Hello World) encrypted with (My Key) as the key"; 
echo $RC4->EnCrypt("Hello World","My Key");
echo "\n";
echo "(x�
+�0�б) encrypted with (My Key) as the key";
echo $RC4->EnCrypt("1�N\�-��","My Key"); 
?>

If you are using ECB mode to encrypt it does not seem to use the iv
(initialization vector) for much of anything, given the same key it will
always decrypt it no matter what the iv is.  If you use CBC mode you must
decrypt with the same iv that you encrypted with. 

 If you use a different iv before decrypting, your decrypt will not work. 
IMHO it seems better to use CBC mode than ECB as ECB will always encrypt
to the same cipher text given the same plain text  (leaving you open to
know plaintext attacks).  CBC uses the random iv which means text encrypts
to different things.  You probably could get the same effect from using
random keys in ECB mode.

Read that in the Schneier book - Applied Cryptography (ISBN 0-471-11709-9)
 This book is a must for anyone seriously using any type of encryption.

If your a windows PHP user, you can download the Mcrypt Encryption
Functions for  in
a nice package.  Too bad their site is down right now   

        :o(