Re: [VOTE] Timing attack safe string comparison function
| From: | Yasuo Ohgaki | Date: | Thu, 06 Feb 2014 04:31:17 +0000 |
| Subject: | Re: [VOTE] Timing attack safe string comparison function | ||
| References: | 1 2 3 4 5 6 7 8 9 | Groups: | php.internals |
| Request: | Send a blank email to internals+get-72316@lists.php.net to get a copy of this message | ||
Sorry for multiple posts.
On Thu, Feb 6, 2014 at 1:20 PM, Yasuo Ohgaki <yohgaki@ohgaki.net> wrote:
> Since comparison of short and/or not hashed data (e.g. user supplied raw
> password) should
> not be done as the function name imply, we may better to document so that
> users always
> compare hashed values even when they store raw password/etc.
> So randomized delay may be overkill.
>
Because user should not pass other than hashed values, we may
return FALSE simply when length mismatches. Generated hashed
length should not be a secret. This get rid of length leak issue and
the function name is good for this purpose and make the operation
always constant.
Regards,
--
Yasuo Ohgaki
yohgaki@ohgaki.netSo