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To: internals@lists.php.net,Stas Malyshev <smalyshev@sugarcrm.com>
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Date: Mon, 23 Dec 2013 10:20:46 +0000
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Subject: Re: [PHP-DEV] [RFC] Timing attack safe string comparison function
From: krakjoe@php.net (Joe Watkins)

On 12/23/2013 10:11 AM, Stas Malyshev wrote:
> Hi!
>
>> I'd like to propose this RFC to introduce a time-constant string
>> comparison function: https://wiki.php.net/rfc/timing_attack
>
> I wonder how practical this would be. There are probably many side
> channels in PHP related to how PHP manages memory, copies variables,
> processes opcodes, etc. so I wonder if providing such function for PHP
> API would practically add anything or if you should be doing crypto that
> sensitive in PHP anyway?
>

One of the chaps on SO done a bit of testing, it appears that without 
usleep in php land you cannot avoid cpu spikes, and so cannot get a 
reliable vector of attack unless the server side code has been prepared 
to be attacked. But this is only testing.

I see the things you see, however, probably better to do something than 
nothing I think, this is technically the correct thing to do, and is 
simple enough, so I say do it ...

Cheers
Joe