DES resists linear cryptanalysis --- the best linear attack on DES is 2^43 and requires 2^43 known plaintexts. Linear cryptanalysis of FEAL-8 takes just 4000 plaintexts.
According to Don Coppersmith, NSA picked DES's s-boxes by randomly generating them and choosing the ones that best resisted differential cryptanalysis --- again, this is something NSA did fifteen years before differential cryptanalysis was discovered by the public. They modified DES to resist an attack only they knew about.
According to Don Coppersmith, NSA picked DES's s-boxes by randomly generating them and choosing the ones that best resisted differential cryptanalysis --- again, this is something NSA did fifteen years before differential cryptanalysis was discovered by the public. They modified DES to resist an attack only they knew about.