[Cryptography] updating a counter

[Stephan Neuhaus]

On 2014-05-19, 20:14, Krisztián Pintér wrote:
> however. what is the design rationale behind the number of rounds in
> a cipher? it is exactly to mask *any* correlation between the input
> and the output. ciphers are designed to support straight up counter
> mode. in other words, your cipher already contains the "diffusion
> rounds". you don't need to do a thing.

Precisely. If I understand things correctly, there is (or ought to be)
zero correlation between encrypt(x) and encrypt(x + 1) for a good block
cipher.

But of course, not being a cryptographer, I'd love to learn otherwise.

Fun,

Stephan