The Institute for Defense Analyses, based in Alexandria, VA, is a 50-year partner of NSA. It has two Centers for Communications Research at Princeton, NJ, and La Jolla, CA, both doing cryptological research for NSA: http://www.idaccr.org/ http://www.ccrwest.org/ The latter's web site lists only this offering: [Quote] La Jolla Covering Repository A (v,k,t)-covering design is a collection of k-element subsets, called blocks, of {1,2,...,v}, such that any t-element subset is contained in at least one block. This site contains a collection of good (v,k,t)-coverings. Each of these coverings gives an upper bound for the corresponding C(v,k,t), the smallest possible number of blocks in such a covering design. The limit for coverings is v<100, k<=25, and t<=8 just to draw the line somewhere. Only coverings with at most 100000 blocks are given, except for some which were grandfathered in. Some Steiner systems (coverings in which every t-set is covered exactly once) which are too big for the database will be included in the link below. [Unquote] What is "covering" and how does it related to cryptology? ----- Eyeballs of the two centers: http://cryptome.org/2013-info/09/nsa-ccr/nsa-ccr.htm