Can anyone give me a good reason that DES/3DES keys must have odd parity, I can’t see a reason for it myself. It might still be a strong cypher if it weren’t for the loss of 8 bits per key

I guess some implementations don’t check for and strip the parity bits, but in that case they become a DES variant, and in FIPS compliant environments that’s not an option anyway.

The simplest answer is probably “because thats the way is was designed”, still there must be a reason