Cuckoo Cycle

This PoW requires finding a 42-cycle in a huge graph whose edges are generated by the siphash-2-4 hash function. The amount of memory needed (with no known practical trade-off for time) is configurable from a few KB to several GB, while remaining instantly verifiable. 67% of run time is spent waiting for memory latency, making this an extremely low-power and GPU unfriendly algorithm.


Details and implementation