[Cryptography] State of sin (was Re: What to put in a new cryptography course)

[Ray Dillinger]

On 07/27/2016 10:13 AM, Ron Garret wrote:
> 
> You didn’t include any context so it’s hard to know exactly what
> you’re referring to here, but I think you’re attacking a straw man.
> All of the references to brute-force in this discussion have been to
> brute-force searches for *algorithms*, not brute-force searches for
> keys.
> 

In general, I refer to the fact that enumerating all
possible proofs is the same method for finding whether
a cipher is secure, as enumerating all possible keys
is a method for finding an encryption key.  (an
encryption key, after all, is a particular bit
string which we can prove has some property with
respect to another bit string).

One could in theory base a secure cipher on the
problem of finding mathematical proofs that the
equations governing particular problems are secure,
just as we normally do with ciphers which are proofs
that particular numbers have particular properties
relative to the boolean equations that comprise
the cipher algorithm.

But how would you prove that such a hypothetical
cipher were secure?  Oh, wait (Wait forever, in
fact).  Didn't we say that the Halting problem was
one we wouldn't necessarily need to address?

				Bear


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