Tags: lcg truncated-lcg lll 

Rating:

tldr;
- the task is to break a truncated LCG given some LSB and some MSB
- the LCG uses an unknown increment
- this paper https://www.math.cmu.edu/~af1p/Texfiles/RECONTRUNC.pdf gives an overview on how to break the LCG
- LLL -> win
- read the writeup for actual details

[DUCTF GitHub](https://github.com/DownUnderCTF/Challenges_2020_public/tree/master/crypto/lsb-msb-calculation-game)

[writeup](https://www.josephsurin.me/posts/2020-09-20-downunderctf-2020-writeups#lsb-msb-calculation-game)

Original writeup (https://www.josephsurin.me/posts/2020-09-20-downunderctf-2020-writeups#lsb-msb-calculation-game).