Tags: z3 

Rating: 3.0

Full writeup: https://github.com/p4-team/ctf/tree/master/2017-08-25-hackit/crypto150

tl;dr: recover list of `lsb` used for encryption of known plaintext part, use Z3 to generate constraints on the key parameters based on those `lsb`

Original writeup (https://github.com/p4-team/ctf/tree/master/2017-08-25-hackit/crypto150).