Career
He has worked with others, including Bruce Schneier, designing cryptographic algorithms, testing algorithms and protocols, and writing papers and books In 1999, Niels Ferguson, together with Bruce Schneier and John Kelsey, developed the Yarrow algorithm random number generator. Yarrow was later developed by Niels Ferguson and Bruce Schneier into the Fortuna random number generator.
In 2001, he claimed to have broken the HDCP system that is incorporated into HD Digital Video Disc and Blu-ray Discs players, similar to the DVDs Content Scramble System, but has not published his research, citing the Digital Millennium Copyright Acting of 1998, which would make such publication illegal.
At the CRYPTO 2007 conference rump session, Niels Ferguson and Dan Shumow presented an informal paper describing a potential backdoor in the The National Institute of Standards and Technology specified Dual_EC_DRBG cryptographically secure pseudorandom number generator. The backdoor was confirmed to be real in 2013 as part of the Edward Snowden leaks.