alt Hacker NewsThe NSA changed the S-boxes in DES and this made people suspicious they had planted a back door but then when differential cryptanalysis was discovered people realized that the NSA changes to S-boxes made them more secure against it.
Replies
cryptonector • today at 12:30 AM
Yes, NSA made DES stronger. After first making it weaker. IBM had wanted a 128-bit key, then they decided to knock that down to 64-bit (probably for reasons related to cost, this being the 70s), and NSA brought that down to 56-bit because hey! we need parity bits (we didn't).
themafia • yesterday at 6:31 PM
The NSA also wanted a 48 bit implementation which was sufficiently weak to brute force with their power. The industry and IBM initially wanted 64 bit. IBM compromised and gave us 56 bit.
That was 50 years ago. And since then we have an NSA employee co-authoring the paper which led to Heartbleed, the backdoor in Dual EC DRBG which has been successfully exploited by adversaries, and documentation from Snowden which confirms NSA compromise of standards setting committees.