[A51] New A5/1 attack patented

Sylvain Munaut 246tnt at gmail.com
Thu Dec 27 04:43:32 CET 2012

> Elad Barkan and Eli Biham (them again) filed a patent which was made
> public 2 months ago. It appears to be a new attack against A5/1:
>   http://www.google.com/patents/US8295477

I've just did a quick scan through it and didn't really see what's
"new" about it ...

The abstract seems to describe the very well known A5/2 attack and
it's optimization. They also describe in the invention the classic
downgrade attacks (sinceit all A5/x share the same Kc, you attack A5/2
or A5/1 using an imsi catcher and reuse the found Kc to decrypt
intercepted A5/3 data for eg).

Can you pin point exactly what "new" about it ?

AFAICT it's just the exact stuff they published 10 years ago ...



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