0
$\begingroup$

Suppose somewhere is Fibonacci LFSR, we know that it has 7 cells and feedback taps are cell 2 and 7.

We intercepted part of a stream, and part intercepted is 1010101.

Is it possible to recover (preceeding)previous bits from this stream using this information?

$\endgroup$

1 Answer 1

2
$\begingroup$

Yes. just run the lfsr backwards, so if you have $$s(t)=s(t-2)+s(t-7)$$ use $$s(t-7)=s(t-2)+s(t)$$ all mod 2 with $$(s(-6),\ldots,s(0))=(1,0,1,0,1,0,1)$$ your initial loading.

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.