hecmas / pil-lfsr

PIL LFSR

Implementation of a Linear-Feedback Shift Register (LFSR) in PIL.

TODOS

• Generalize it to the setting where the taps are private inputs, so that you can generate a (zk-)STARK of a statement such as:

  The output of my LFSR is X, given a (secret) configuration C and a (possibly public) inital state X_0.

• Add a PIL constraint checking that the configuration is appropriate. That means that the period generated by the taps must be $2^{10}-1$.

• Generalize it to the setting were degree (number of bits) of the LFSR is chosen by the user.

Resources

• Wikipedia is (almost) always helpful for doing basic cryptography here.
• Spanish explanation of LFSRs here. They use them to encrypt a song!