MD5 collision in X509 certificates

[Dan Kaminsky]

Ben Laurie wrote:

> Dan Kaminsky wrote:
>
>>     The x.509 cert collision is a necessary consequence of the earlier
>> discussed prime/not-prime collision.  Take the previous concept, make
>> both prime, and surround with the frame of an x.509 cert, and you get
>> the new paper.
>
>
> Actually, not - an RSA public key is not prime. Generating colliding
> public keys takes quite a bit more work.

*laughs* Yes, I suppose it would be difficult for pq to be prime now
wouldn't it :)

So they've basically solved:

md5(pq) == md5(p'q')

For integer values of p, q, p' and q'.  You are right, this is much more
work.

--Dan


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