Dagger appears to be inferior to the Cuckoo Cycle proof of work system I recently developed; see
https://github.com/tromp/cuckooCuckoo Cycle is a new proof of work system with the following features
1) proofs take the form of a length 42 cycle in the Cuckoo graph, so that verification only requires computing 42 hashes.
2) the graph size (number of nodes) can scale from 1x2^10 to 7x2^29 with 4 bytes needed per node, so memory use scales from 4KB to 14GB
3) running time is roughly linear in memory, at under 1s/4MB
4) there is no time-memory trade-off, and memory access patterns are the worst possible, making the algorithm constrained by memory latency
5) it has a natural notion of difficulty, namely the number of edges in the graph; above about 60% of size, a 42-cycle is almost guaranteed, but below 50% the probability starts to fall sharply
