@misc{cryptoeprint:2015:575,
author = {Céline Blondeau and Thomas Peyrin and Lei Wang},
title = {Known-key Distinguisher on Full PRESENT},
howpublished = {Cryptology ePrint Archive, Report 2015/575},
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.