----- Forwarded message from Maxim Kammerer ----- Date: Thu, 15 Aug 2013 15:38:56 +0300 From: Maxim Kammerer To: liberationtech Subject: Re: [liberationtech] Google confirms critical Android crypto flaw Reply-To: liberationtech On Thu, Aug 15, 2013 at 2:34 PM, Nathan of Guardian wrote:

The best description is here: http://armoredbarista.blogspot.ch/2013/03/randomly-failed-weaknesses-in-java...

Unbelievable… It seems that PRNG implementers suffer from NIH syndrome. If you are going to use /dev/urandom, then use it all the time, and rely on code that's reviewed and maintained by thousands of kernel people, not just your favorite buggy seeded PRNG du-jour. And even sans the bugs, consider something like the following in Apache Harmony (precursor of Dalvik's class library) [1, p. 131]: iv = sha1(iv,concat(state, cnt)); cnt = cnt + 1; return iv; So they're essentially constructing a state-based bit stream that varies in each block, and hash it with SHA-1 — exposing each intermediate hash value in the middle. Who the hell told them it's safe from cryptanalysis POV? E.g., SP800-90A's Hash_DRBG [2, p. 40] resembles nothing of the sort. [1] http://dx.doi.org/10.1007/978-3-642-36095-4_9 [2] http://csrc.nist.gov/publications/nistpubs/800-90A/SP800-90A.pdf -- Maxim Kammerer Liberté Linux: http://dee.su/liberte -- Liberationtech is a public list whose archives are searchable on Google. Violations of list guidelines will get you moderated: https://mailman.stanford.edu/mailman/listinfo/liberationtech. Unsubscribe, change to digest, or change password by emailing moderator at companys@stanford.edu. ----- End forwarded message ----- -- Eugen* Leitl <a href="http://leitl.org">leitl</a> http://leitl.org ______________________________________________________________ ICBM: 48.07100, 11.36820 http://ativel.com http://postbiota.org AC894EC5: 38A5 5F46 A4FF 59B8 336B 47EE F46E 3489 AC89 4EC5