RE: Secure random ID generation

From: Ryan M Harris (rmharrisat_private)
Date: Tue Dec 03 2002 - 12:17:42 PST

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    Yeah, the seeding is done in a separate section of code...  I should
    have included that in the email.  Sorry about that.  I will probably use
    a yarrow derivative for the PRNG.  Shortly after I posted the message I
    came across the "mersenne twister" home page which stated that it was
    not secure.  I have since read that it "may be" which is why I did not
    withdraw the previous post.
    
    Ryan
    
    -----Original Message-----
    From: David Wagner [mailto:dawat_private] 
    Sent: Tuesday, December 03, 2002 12:26 PM
    To: secprogat_private
    Subject: Re: Secure random ID generation
    
    Ryan M Harris wrote:
    >I have a batch of code that is to be used for secure session
    identifiers
    >in a network security system, can you tell me if this formula is good
    >for that type of environment.
    
    No, it is not. Your PRNG ("Mersenne twister") is not cryptographically
    strong. And you never took any care to ensure that the PRNG was seeded,
    which is a very common failure mode.
    
    You can find some information on how to do this right at
    http://www.cs.berkeley.edu/~daw/rnd/index.html
    



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