What's the status of Momentum POW? Was it used in Bitshares? Is it used in any coin?
It is broken beyond repair according to
https://eprint.iacr.org/2015/946.pdfTheir Proposition 9 states a sublinear time-memory tradeoff.
For instance, collisions can be found in memory O(sqrt(N)) and time O(N^(5/4)),
instead of memory and time O(N).
This Proposition is based on the golden collision search technique, described in Section 4.2 of
http://people.scs.carleton.ca/~paulv/papers/JoC97.pdf