hi,

I looking for an algoritm to encrypt some data sent from a c program(client) to a php server(can be in perl or cgi-bin) over the internet.

How should i send it in c? Some http call? Or it can be in via a perl script.

Then i need some basic algoritm to encrypt it. Any ideas. How do i save the key in the c program? Just something basic so its not clear text. This is not for a bank or visacards etc

Any idees? Thanks for any help or leeds.

ok i found this: http://www.ficgs.com/How-to-crypt-an...ypt-s3141.html

and base64_encode and base64_decode does exist in PHP as in c.

Now i have to translate this to php and figure out how to handle the keys for different versions etc.

Happy programming!



How to crypt and decrypt ?

Every programmer at least once look for a good way to encrypt with the possibility to decrypt. Md5 and Sha1 are not convenient in this case as it is not possible to decrypt with these functions.

Here are nice functions that will help you to encrypt and decrypt with a key :

<?

function encrypt($string, $key)
{
$string = 'STT576PWZA'.$string;

$result = '';
for($i=0; $i<strlen($string); $i++)
{
$char = substr($string, $i, 1);
$keychar = substr($key, ($i % strlen($key))-1, 1);
$char = chr(ord($char)+ord($keychar));
$result.=$char;
}

return base64_encode($result);
}

function decrypt($string, $key)
{
$result = '';
$string = base64_decode($string);

for($i=0; $i<strlen($string); $i++)
{
$char = substr($string, $i, 1);
$keychar = substr($key, ($i % strlen($key))-1, 1);
$char = chr(ord($char)-ord($keychar));
$result.=$char;
}

$result = substr($result,10,strlen($result));

return $result;
}

?>


Note that here the string to encrypt is added to 10 characters, this may not be useful but it is just a way to add kind of salt.

It works fine anyway !

You might also want to look at gnutls, which can give you an encrypted session. It's pretty easy to use once you understand it, and TLS is also available for PHP (though I haven't used it.)
Kevin Barry