full-disclosure - Israeli boffins crack GSM code

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From: damian at sentex.net (Damian Gerow)
Subject: Israeli boffins crack GSM code

Thus spake Gregory A. Gilliss (ggilliss@...publishing.com) [09/09/03 14:11]:
> Sorry, which GSM code would this be? Because I distinctly remember being
> at a party years ago where the GSM code (some weak variant of A5) was
> shown to be weak and hackable.  This was back in 1998...

Discussion on the cryptography mailing list indicated that all this does is
force a downgrade from A5/3 to A5/2, which can then be cracked.  I can't
find the archives online, so I'll paraphrase...

The attack forces the terminal end of the call to use A5/2, which is known
to be insecure.  It then cracks the key, and continues to use this cracked
key for A5/3.  A5/3 itself still hasn't been cracked, it looks like it's
just the initial negotiation.