I am not sure that the general conclusion is warranted. See for example the cryptopals exercise https://cryptopals.com/sets/4/challenges/31 https://cryptopals.

I am not sure that the general conclusion is warranted. See for example the cryptopals exercise https://cryptopals.com/sets/4/challenges/31 https://cryptopals.com/sets/4/challenges/31 Experience has shown that this is even detectable remotely. When auditing any cryptographic library, this is one of the first things I look for.