I lost you at the second paragraph. Crypto researches generally agree today that the NSA actually chose strong contents for DES (I assume that's what you meant by DEC?). They invented differential cryptanalysis a decade before anyone else, and used that to strengthen the cypher. Everyone suspected their motives at the time, but eventually academy caught up with the knowledge the NSA had, and could show that the constants are in fact good.

Too bad they're doing the opposite of that nowadays...