Quote from: CRServers on January 24, 2015, 03:11:27 PM

Hello to all!

I recently gave a talk about Bitcoin to a group of business and university professors, and in that talk I said that Satoshi Nakamoto had solved the "Bizantine Generals Problem".

I had read that from several documents and also heard it from a couple of prominent Bitcoin talkers.
To my surprise, one professor disputed my affirmation, got up, and said that another person had solved it before. He mentioned the name but I forgot it.

Now I'm perplexed about the issue and want to know what the real story is, so I can contact this person and conciliate the truth with him.

Can anybody point me to some authoroitative evidence on this subject so I can refute or accept this guy's claim?

Thanks a lot,

Rodrigo

RPOW was added on top of Adam Backs HashCash. (This is how Hal Finney created the solution for the Byzantine Generals Problem which allowed BitGold/Bitcoin to be completed).

-The computer can be used as a tool to liberate and protect people, rather than to control them ~ Hal

To: cypherpunks@al-qaeda.net
Subject: RPOW - Reusable Proofs of Work
Date: Sun, 15 Aug 2004 10:43:09 -0700 (PDT)
From: hal at finney dot org ("Hal Finney")

I'd like to invite members of this list to try out my new
hashcash-based server, rpow.net.

This system receives hashcash as a Proof of Work (POW) token, and in
exchange creates RSA-signed tokens which I call Reusable Proof of Work
(RPOW) tokens. RPOWs can then be transferred from person to person and
exchanged for new RPOWs at each step. Each RPOW or POW token can only
be used once but since it gives birth to a new one, it is as though the
same token can be handed from person to person.

Because RPOWs are only created from equal-value POWs or RPOWs, they are
as rare and "valuable" as the hashcash that was used to create them.
But they are reusable, unlike hashcash.

The new concept in the server is the security model. The RPOW server
is running on a high-security processor card, the IBM 4758 Secure
Cryptographic Coprocessor, validated to FIPS-140 level 4. This card
has the capability to deliver a signed attestation of the software
configuration on the board, which any (sufficiently motivated) user
can verify against the published source code of the system. This lets
everyone see that the system has no back doors and will only create RPOW
tokens when supplied with POW/RPOW tokens of equal value.

This is what creates trust in RPOWs as actually embodying their claimed
values, the knowledge that they were in fact created based on an equal
value POW (hashcash) token.

I have a lot more information about the system at rpow.net, along with
downloadable source code. There is also a crude web interface which
lets you exchange POWs for RPOWs without downloading the client.

This system is in early beta right now so I'd appreciate any feedback
if anyone has a chance to try it out. Please keep in mind that if there
are problems I may need to reload the server code, which will invalidate
any RPOW tokens which people have previously created. So don't go too
crazy hoarding up RPOWs quite yet.

Thanks very much -

Hal Finney
http://cryptome.org/rpow.htm

Szabo(BitGold), and apparently Satoshi(BitCoin), realized that Hal Finneys RPOW could be used to solve the Byzantine Generals Problem, a problem in ordinary computing that demonstrates through game theory how a group of potential co-operators can come to the best consensus even with the possibility of having malicious operators among them. This was the final piece to the BitGold/Bitcoin puzzle.
http://www.cs.cornell.edu/courses/cs614/2004sp/papers/lsp82.pdf
http://unenumerated.blogspot.com/2008/04/bit-gold-markets.html?m=1
http://unenumerated.blogspot.com/2005/12/bit-gold.html?m=1

Nick Szabo: (assuming Nakamoto is not really Finney or Dai)..Only Finney (RPOW) and Nakamoto were motivated enough to actually implement such a scheme.

Szabo has now coined the phrase "Nakamoto Consensus" to refer to Hal's "RPOW" that Satoshi used to make BitCoin work.
http://unenumerated.blogspot.com/2014/12/the-dawn-of-trustworthy-computing.html