[130179] in cryptography@c2.net mail archive

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Re: OpenID/Debian PRNG/DNS Cache poisoning advisory

daemon@ATHENA.MIT.EDU (Ben Laurie)
Fri Aug 8 16:02:55 2008

Date: Fri, 8 Aug 2008 20:10:41 +0100
From: "Ben Laurie" <benl@google.com>
To: "Tim Dierks" <tim@dierks.org>
Cc: "Dan Kaminsky" <dan@doxpara.com>,
        "Eric Rescorla" <ekr@networkresonance.com>,
        "Dave Korn" <dave.korn@artimi.com>, bugtraq@securityfocus.com,
        security@openid.net, "OpenID List" <general@openid.net>,
        cryptography@metzdowd.com, full-disclosure@lists.grok.org.uk
In-Reply-To: <aafe62bf0808081154i62fb15bfp6153938d1bb90ce6@mail.gmail.com>

On Fri, Aug 8, 2008 at 7:54 PM, Tim Dierks <tim@dierks.org> wrote:
> Using this Bloom filter calculator:
> http://www.cc.gatech.edu/~manolios/bloom-filters/calculator.html , plus the
> fact that there are 32,768 weak keys for every key type & size, I get
> various sizes of necessary Bloom filter, based on how many key type / sizes
> you want to check and various false positive rates:
>  * 3 key types/sizes with 1e-6 false positive rate: 2826759 bits = 353 KB
>  * 3 key types/sizes with 1e-9 false positive rate: 4240139 bits = 530 KB
>  * 7 key types/sizes with 1e-6 false positive rate: 6595771 bits = 824 KB
>  * 7 key types/sizes with 1e-9 false positive rate: 9893657 bits = 1237 KB
>
> I presume that the first 3 & first 7 key type/sizes in this list
> http://metasploit.com/users/hdm/tools/debian-openssl/ are the best to
> incorporate into the filter.
>
> Is there any chance it would be feasible to get a list of all the weak keys
> that were actually certified by browser-installed CAs, or those weak
> certificates? Presumably, this list would be much smaller and would be more
> effectively distributed in Bloom filter form.

Or as a CRL :-)

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