@misc{cryptoeprint:2013:806,
author = {Somindu C. Ramanna and Palash Sarkar},
title = {Efficient (Anonymous) Compact HIBE From Standard Assumptions},
howpublished = {Cryptology ePrint Archive, Report 2013/806},
year = {2013},
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.