[Cryptography] List of Proven Secure Ciphers / Hashes

[Bear]

On Fri, 2014-09-05 at 13:52 -0400, Jerry Leichter wrote:

> Whether "is in NP" or even "is NP complete" is relevant to cryptography
> is something one can debate - though not very much, as the answer is
> clear:  No.  

> But if you're going to talk about a technical matter, you have to use
> the language as it's understood in the community.

NP problems are those for which we do not know whether any
polynomial-time solution exists.  In practice all successful 
modern ciphers are based on NP problems. 

For cryptography we want problems that are hard;  but it doesn't 
really matter whether they are hard in a way that is proportional 
to an exponential (non-polynomial)function or hard in a way that 
is proportional to some polynomial of very high degree. It only 
matters that they are too hard for solving them to be likely or
practical.

For example, if there is some problem whose difficulty is O(N^50)
for N-bit keys of at least some minimum size, then it isn't NP, 
but it could be suitable for cryptography anyway. 

			Bear