@misc{cryptoeprint:2011:548,
author = {V.O. Drelikhov and G.B. Marshalko and A.V. Pokrovskiy},
title = {On the security of MQ_DRBG},
howpublished = {Cryptology ePrint Archive, Report 2011/548},
year = {2011},
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.