Trouble decrypting data

[laredotornado@zipmail.com]

Hi,

I am using PHP 4.4.3 and trying to encrypt and decrypt data. Below are
my functions. The problem is that when I run this code, different
results are printed out ...

require("util_f ns.php");
$data = "wood";
$encData = encryptData($da ta);
$decData = decryptData($en cData);
// This prints out "wood" and then "wood" with a bunch of junk
after it.
print "$data<BR>\n$de cData<BR>\n";

Could someone help me correct what's wrong? Thanks, - Dave

function encryptData($p_ str)
{
if (ENCRYPTION_ENA BLED) {
$iv_size = mcrypt_get_iv_s ize(MCRYPT_XTEA ,
MCRYPT_MODE_ECB );
$iv = mcrypt_create_i v($iv_size, MCRYPT_RAND);

$enc = mcrypt_encrypt( MCRYPT_XTEA,
ENCRYPTION_KEY, $p_str, MCRYPT_MODE_ECB , $iv);
return $enc;
} else {
return $p_str;
} // if
} // encryptData

function decryptData($p_ str)
{
if (ENCRYPTION_ENA BLED) {
$iv_size = mcrypt_get_iv_s ize(MCRYPT_XTEA ,
MCRYPT_MODE_ECB );
$iv = mcrypt_create_i v($iv_size, MCRYPT_RAND);
$crypttext = mcrypt_decrypt( MCRYPT_XTEA,
ENCRYPTION_KEY, $p_str, MCRYPT_MODE_ECB , $iv);
return $crypttext;
} else {
return $p_str;
} // if
} // decryptData

[Benjamin]

Re: Trouble decrypting data

I would suggest you take a look at the mcypt functions found at

http://www.php.net/mcrypt

you need to call mcrypt_module_o pen first to get a module then pass it
as the first parameter for the rest of the functions. I would suggest
you look at the documentation for all the params
laredotornado@z ipmail.com wrote:

Hi,
>
I am using PHP 4.4.3 and trying to encrypt and decrypt data. Below are
my functions. The problem is that when I run this code, different
results are printed out ...
>
require("util_f ns.php");
$data = "wood";
$encData = encryptData($da ta);
$decData = decryptData($en cData);
// This prints out "wood" and then "wood" with a bunch of junk
after it.
print "$data<BR>\n$de cData<BR>\n";
>
Could someone help me correct what's wrong? Thanks, - Dave
>
function encryptData($p_ str)
{
if (ENCRYPTION_ENA BLED) {
$iv_size = mcrypt_get_iv_s ize(MCRYPT_XTEA ,
MCRYPT_MODE_ECB );
$iv = mcrypt_create_i v($iv_size, MCRYPT_RAND);
>
$enc = mcrypt_encrypt( MCRYPT_XTEA,
ENCRYPTION_KEY, $p_str, MCRYPT_MODE_ECB , $iv);
return $enc;
} else {
return $p_str;
} // if
} // encryptData
>
function decryptData($p_ str)
{
if (ENCRYPTION_ENA BLED) {
$iv_size = mcrypt_get_iv_s ize(MCRYPT_XTEA ,
MCRYPT_MODE_ECB );
$iv = mcrypt_create_i v($iv_size, MCRYPT_RAND);
$crypttext = mcrypt_decrypt( MCRYPT_XTEA,
ENCRYPTION_KEY, $p_str, MCRYPT_MODE_ECB , $iv);
return $crypttext;
} else {
return $p_str;
} // if
} // decryptData

[veg_all@yahoo.com]

Re: Trouble decrypting data

laredotornado@z ipmail.com wrote:

Hi,
>
I am using PHP 4.4.3 and trying to encrypt and decrypt data. Below are
my functions. The problem is that when I run this code, different

the problem is the initialization vector is different each time . you
would need to use the same $iv to get the same result. i can paste
some code using rijndael-128 if interested.

[laredotornado@zipmail.com]

Re: Trouble decrypting data

Please do.

Thanks, - Dave

veg_all@yahoo.c om ha escrito:

laredotornado@z ipmail.com wrote:

Hi,

I am using PHP 4.4.3 and trying to encrypt and decrypt data. Below are
my functions. The problem is that when I run this code, different

>
the problem is the initialization vector is different each time . you
would need to use the same $iv to get the same result. i can paste
some code using rijndael-128 if interested.

[veg_all@yahoo.com]

Re: Trouble decrypting data

here is some untested code i pasted below: basically the iv,
initailization vector is prepended to the encrypted data.

////////////////////////////////

function aes_encrypt ($input) {

global $key;

$td = mcrypt_module_o pen('rijndael-128', '', 'cbc', '');

// iv = initiailization _vector;

$iv = mcrypt_create_i v (mcrypt_enc_get _iv_size($td), MCRYPT_RAND );

mcrypt_generic_ init($td, $key, $iv);

$encrypted_data = mcrypt_generic( $td, $input);

mcrypt_generic_ deinit($td);
mcrypt_module_c lose($td);

$encrypted_data = bin2hex ( $iv ) . bin2hex ( $encrypted_data );

return $encrypted_data ;

} // end function

//////////////////////////////

function aes_decrypt ( $input ) {

global $key;

$iv = substr ( $input, 0, 32 );
$iv = pack ( H32, $iv );

$input = substr ( $input, 32, strlen ( $input ) );
$input =pack("H" . strlen ( $input ) , $input );

$td = mcrypt_module_o pen('rijndael-128', '', 'cbc', '');

mcrypt_generic_ init($td, $key, $iv);

$dec = mdecrypt_generi c($td, $input );

mcrypt_generic_ deinit($td);
mcrypt_module_c lose($td);

return trim ( $dec );

} // end function

//////////////////////////////