@misc{cryptoeprint:2015:344,
author = {Ryo Nishimaki and Daniel Wichs},
title = {Watermarking Cryptographic Programs Against Arbitrary Removal Strategies},
howpublished = {Cryptology ePrint Archive, Report 2015/344},
year = {2015},
note = {\url{http://eprint.iacr.org/}},
}
You will need the url.sty package (comes with most LaTeX installations) for the last line. Otherwise, remove the \url command.