Alex Biryukov, Dmitry Khovratovich. Asymmetric proof-of-work based on the Generalized Birthday problem. IACR Cryptology ePrint Archive, 2015:946, 2015. [doi]
@article{BiryukovK15b,
title = {Asymmetric proof-of-work based on the Generalized Birthday problem},
author = {Alex Biryukov and Dmitry Khovratovich},
year = {2015},
url = {http://eprint.iacr.org/2015/946},
researchr = {https://researchr.org/publication/BiryukovK15b},
cites = {0},
citedby = {0},
journal = {IACR Cryptology ePrint Archive},
volume = {2015},
pages = {946},
}