Is it possible that 4% of the time, you have spaces on the start/end
of the string, which get trimmed before encryption?
And if rijndael is one of the algorithms which requires a fixed-size
input, that also would be "bad" to trim it. If you need multiple of
16 bytes input, leave the input alone.
Actually, I'd suggest that the encryption function has no business
trimming the text anyway.
If I want to jagencdecr(str_repeat(' ', 1000), 'E'), then I probably
don't want the function to trim that, eh? :-)
On Tue, January 15, 2008 6:54 pm, Ken Kixmoeller -- reply to
ken@xxxxxxxxxxxxxx wrote:
> Hey --- - -
>
> I am in the process of upgrading the encryption technology I am using
> from (64 bit) blowfish to (256 bit) rijndael.
>
> The code (and some explanations) is below, but the results are, um,
> unusual, and I can't see what I am doing wrong. For testing, I have a
> program that generates a random 16-character string, encrypts it to a
> variable, and decrypts it. Running it in 500 iteration loops, it
> fails roughly 4% of the time. By "fails" I mean that the original
> string and the eventual decrypted one don't match.
>
> Anybody able to spot why?
>
> Ken
> --------------------------------------
> function jagencdecr($text,$EorD,$encpass='') {
> // parameters:
> // - $text = string to be en/decrypted,
> // - $EorD = Encrypt or Decrypt
> // - $encpass = key phrase
> if (empty($text)) {return "";}
> $text = trim($text);
> $cypher = mcrypt_module_open('rijndael-256', '', 'ecb', '');
> // "ecb" mode produces the above results.
> // "ofb" mode produces 100% errors
>
> $size = mcrypt_enc_get_iv_size($cypher);
> $phprand = rand(1000,9999);
> $iv = mcrypt_create_iv($size,$phprand); // produces the same results
> as below, platform independent
> //$iv = mcrypt_create_iv($size,MCRYPT_RAND); // for Windows
> //$iv = mcrypt_create_iv($size,MCRYPT_DEV_RAND); // for 'NIX
>
> $ks = mcrypt_enc_get_key_size($cypher);
> /* Create key */
> $key = substr(md5($encpass), 0, $ks);
> mcrypt_generic_init($cypher,$key,$iv);
> if ($EorD == "D") {
> $text_out = mdecrypt_generic($cypher,$text);
> } else {
> $text_out = mcrypt_generic($cypher,$text);
> } // endif ($EorD == "D")
> mcrypt_generic_deinit($cypher);
> mcrypt_module_close($cypher);
> return trim($text_out);
>
> } // endfunc jagencdecr Jaguar Ecnrypt/Decrypt
>
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>
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Know what I want?
I want you to buy a CD from some indie artist.
http://cdbaby.com/from/lynch
Yeah, I get a buck. So?
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