On 2010-06-09 11:59, sascha wrote:
> On Wed, Jun 09, 2010 at 08:55:35PM +0300, Ber Lost wrote:
>
>> Thank you for your answers.
>> I have some more questions regarding the procedure.
>>
>> 1.There is a difference between the result from the demo and the code in
>> reference/a51.cpp.The first bit in the 64bit keystream produced from the c++
>> code is the xor of the 19th,22nd,23rd bits whereas in the demo it is the xor
>> after one clocking.Which one is the correct way?
>>
> our original reference code ("A pedagogical implementation of A5/1")
> computes the output bit before the clocking and so do we. Except in the
> demo which is a bug. Note that the reference code has been verified with
> an actual GSM conversation.
>
Just in the interest of historical correctness, the A5/1 code was
reverse engineered from actual GSM equipment, but we did not at the time
build an independent GSM stack to verify the code by performing a call.
That said, various members of the GSM Association and its cryptographic
advisers acknowledged to me that our A5/1 code is correct.
--Lucky Green
_______________________________________________
A51 mailing list
[email protected]
http://lists.lists.reflextor.com/cgi-bin/mailman/listinfo/a51
