@misc{cryptoeprint:2015:677,
author = {Daniel J. Bernstein and Simon Josefsson and Tanja Lange and Peter Schwabe and Bo-Yin Yang},
title = {EdDSA for more curves},
howpublished = {Cryptology ePrint Archive, Report 2015/677},
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.