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Date: Thu, 14 Jun 2012 07:19:59 -0700
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Subject: Re: [PHP-DEV] Adding a simple API for secure password hashing?
From: thruska@cubiclesoft.com (Thomas Hruska)

On 6/14/2012 6:11 AM, Anthony Ferrara wrote:
> Daniel,
>
>> Stas has the right approach, not only should the methods be simplified and
>> platform/algorithm agnostic but have a proper salt built in (there are a
>> few CSPRNG implementations around), I've seen salts used from numbers to
>> md5's to just being skipped altogether.
>
> Well, just to be clear, a salt does not need a CSPRNG. All it needs to
> be is reasonably unique. In fact, I wouldn't make it CS, as that would
> deplete the available entropy in the system for CSPRNG generation.
>
> So in practice, a normal PRNG will suffice. With that said, mt_rand()
> is not enough. It should be a moderately good PSRNG. It just doesn't
> need to be CS. If mcrypt is available, DEV_URANDOM would be a good
> place to get entropy.
>
> Or, we could implement a system like I did in
> https://github.com/ircmaxell/PHP-CryptLib/tree/master/lib/CryptLib/Random
> that follows RFC4086: http://tools.ietf.org/html/rfc4086#section-5.2
> Where it mixes together several sources of weak and moderate strength
> PRNG...

This:

http://barebonescms.com/documentation/csprng/

Takes a different approach.  Generate one or more stored root seeds and 
then use those seeds to generate as much data as is needed without 
risking loss of entropy.  It also accepts extra entropy sources as input 
- even weak sources such as an incrementing integer or serialized 
user-submitted data - to further enhance the output.

Adding more random sources of information to PHP is a good thing.  If 
something like what is being discussed is developed, it will merely 
become one more source for root seed generation.  The more the merrier. 
  Good sources of entropy are hard to come by.

One thing I would like to recommend is add to the documentation that 
certain functions are inappropriate for specific use cases and recommend 
alternative solutions.  A lot of people out there think rand() and 
mt_rand() are suitable for security.  Maybe have a specific page in the 
PHP documentation dedicated to covering random string and number 
generation and link to that page from various function pages.

-- 
Thomas Hruska
CubicleSoft President

Barebones CMS is a high-performance, open source content management 
system for web developers operating in a team environment.

An open source CubicleSoft initiative.
Your choice of a MIT or LGPL license.

http://barebonescms.com/