Posted by Andy Hassall on 11/05/06 23:11

On Sun, 05 Nov 2006 13:45:04 -0500, CharlesL <cl@sd.nl> wrote:

>I am trying to handle binary strings in php. I get a binary output
>initialization vector from mcrypt as such:
>
>from mcrypt:
> $iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
>
>This output may have padded nulls at the end which are significant.
>
>I would like to convert all characters including all padding nulls at
>end and convert it in a string to be saved into a database in such a way
>that I can reconstruct it back to binary again later.
>
>base64_encode and decode is not doing the job. They don't seem to
>preserve the original binary value after base64_decode().

What version are you using? I'm not seeing trimming of trailing nul bytes on
PHP 5.2.0, at least:

andyh@excession /cygdrive/c/public_html
$ cat test.php
<?php
$data = str_repeat(chr(0), 16);

var_dump(unpack('H*', $data));

print base64_encode($data) . "\n";

var_dump(unpack('H*', base64_decode(base64_encode($data))));
?>

andyh@excession /cygdrive/c/public_html
$ php test.php
array(1) {
[1]=>
string(32) "00000000000000000000000000000000"
}
AAAAAAAAAAAAAAAAAAAAAA==
array(1) {
[1]=>
string(32) "00000000000000000000000000000000"
}

(And incidentally pack/unpack may give you another option)

--
Andy Hassall :: andy@andyh.co.uk :: http://www.andyh.co.uk
http://www.andyhsoftware.co.uk/space :: disk and FTP usage analysis tool

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