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NBS and IBM were pushed by NSA to use 56 bit key length instead of 64 for DES. [1] NBS became NIST and they still have credibility to you. Whatever reason you

by lixtra 6y ago

NBS and IBM were pushed by NSA to use 56 bit key length instead of 64 for DES. [1] NBS became NIST and they still have credibility to you. Whatever reason you come up with why it was okay back then also applies today. [1] https://en.m.wikipedia.org/wiki/Data_Encryption_Standard https://en.m.wikipedia.org/wiki/Data_Encryption_Standard

bjoli 6y ago
...While also making it more resistant to differential cryptanalysis (called DCA from now on). DES died because of the small keyspace. Without the NSA/NBS changes it would have been insecure from the start and would have been a lot easier to crack once DCA was out in public. The changes proposed made DES harder to crack for the NSA, but less "future safe" once computational power caught up. I don't know enough about DCA to know whether DCA-weak-DES could have been made safer with something like 3des, but I wouldn't want to bet on it.