Tags: crypto lfsr
Rating:
**Official writeup**
tl;dr
* Find the co-relation between variables in the LFSR equation
+ d == out (75%)
+ a == b (75%)
+ c^d == out (75%)
+ (d!= out) => (c==1) always
* Solve for the seed using 2000 output bits
* Try out which among the possible combinations decrypt the flag
Link to writeup: <https://blog.bi0s.in/2020/08/02/Crypto/LFSR/InCTFi-20-FaultyLFSR/>
Author: [ph03n1x](https://twitter.com/MeenakshiSL1)
