[Cryptography] Proposal of a fair contract signing protocol

Christian Huitema huitema at huitema.net
Tue Jun 21 12:50:05 EDT 2016

On Monday, June 20, 2016 3:24 PM, mok-kong shen wrote:
> Am 20.06.2016 um 05:05 schrieb Peter Fairbrother:
> > On 19/06/16 17:51, mok-kong shen wrote:
> > [..]
> >
> >> [Addendum 19.06.2016] There are literatures which claim (if I have
> >> not
> >> misinterpreted) that protocols of our genre are impossible.
> >
> > They are impossible.
> >
> > This is known as the two generals problem:
> >
> > https://en.wikipedia.org/wiki/Two_Generals%27_Problem
> >
> I should very much appreacite your critically and clearly pointing out
> where/why  my protocal doesn't fulfill its intended purposes.

Sorry, but it is the other way around. The problem that you are trying to solve appears to be the same as the "two generals" problem, which is proven to not have a solution. If you want to see further work on your proposal, then you need to demonstrate first that the "fair signing" problem is not the same as the "two generals" problems.

It is also well known that one can make arbitrarily complicated attempts at solving at the two generals problems: if a simple message + ACK fails, add an ACK of ACK, etc., ad libitum. Given the general result, all these attempts ultimately fail in some obscure way. Spending time about the particular way this or that construct fails generally takes a long time, and is not particularly interesting. 

-- Christian Huitema

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