Re: Ada Connections to this Crypto.

[MM <mrvmurray@gmail.com>]

On Friday, 19 December 2014 01:25:36 UTC+2, Denis McMahon  wrote:
> What adjudicating team do you need? The fact that the plaintext can be 
> created from the ciphertext is sufficient to prove the brute force attack.

Not to O'Byrne it isn't.

> Publishing the plaintext (or a link to it) here here would be proof of 
> the success of the bruteforce attack.

So you'd think.

> To put it another way, if all you supply me with is the ciphertext and I 
> can publish the plaintext, then obviously the cipher has failed!

Not the way O'Byrne plays the game.

A year or two back, a challenge was to break a ciphertext given that
"two small integers"[*] were sufficient to provide the security. He cheated
by not sticking to the game plan. His previously cleartext "scrambling
parameters", Which were supposed to be cleartext knowledge, suddenly
became secret, and he changed them surreptitiously.

He therefore created a cipher text that his "Bob" couldn't read, and for 
which my brute-force program needed rewriting. I looked at how to do this,
and while I didn't complete the job, I saw that his ciphertext, when plotted
as a graph, leaked those parameters heavily, thus offering a clear attack.

I demonstrated my program on his example plaintext/ciphertext examples,
where it did not need his "small integers" to decrypt, and did this by brute
force.

He made some cockamamy excuse about "needing to protect his cipher",
showing that he had no clue about how such challenges work. He ignored
the fact that my brute-force program could break his example ciphertexts
in seconds. A previous challenge with his other cipher solicited a similar
/post hoc/ excuse for that cipher's failure.

I didn't see much point in continuing, at that point. If he wasn't going to
display any integrity, then the game was over.

This is why he needs an adjudicator, and this is why the challenge reward
needs to be in escrow and substantial.

M

[*] "Two small integers" turned out to be "three small integers", but he kept
referring to two numbers, not three. You may have noticed in his writing that
he doesn't often make a lot of sense. If you could be bothered to compare
his verbal description his cipher with the Ada code, its clear he is very
confused about a lot of things.