Proof of Work and connect with BYZANTINE Generals

THIS PRESENTATION
WILL COVER THE STORY OF
BYZANTINE GENERALS
& WHY IS IT IMPORTANT FROM A
BLOCKCHAIN PERSPECTIVE?

ATTEMPTING
TO EXPLAIN THE SAME IN A
FORM
FOR EASY
ASSIMILATION

BYZANTINE GENERAL CONSENSUS
IN THE BACK OLD DAYS,THERE WERE TWO
ARMY’S 1 & 2, DESIRING TO ATTACK A
ENEMY FORT
ARMY 1 ARMY 2
ENEMY FORT TO BE
ATTACKED

CONDITION IS THAT BOTH HAVE TO
ATTACK AT THE SAME TIME,ELSE THEY
LOOSE
ARMY 1 ARMY 2
ENEMY FORT TO BE
ATTACKED

SO A CONSENSUS IS REQUIRED
(WHAT DAY/TIME TO ATTACK)
ARMY 1 ARMY 2
ENEMY FORT TO BE
ATTACKED

MESSENGER SENT FROM 1 TO 2
ARMY 1 ARMY 2
ENEMY FORT TO BE
ATTACKED

MESSENGER SENT FROM 2 TO 1
ARMY 1 ARMY 2
ENEMY FORT TO BE
ATTACKED

BOTH GENERALS AGREE AS PER
EXCHANGE OF MESSAGE
ARMY 1 ARMY 2
ENEMY FORT TO BE
ATTACKED

MESSENGER IS

MESSAGE HAS CHANCES OF
BEING COMPROMISED

SECURE COMMUNICATION
REQUIRED
ARMY 1 ARMY 2
ENEMY FORT TO BE
ATTACKED

HOW TO ENSURE GUARANTEED
UNALTERED MESSAGE EXCHANGE?
ARMY 1 ARMY 2
ENEMY FORT TO BE
ATTACKED

“In fact it was proved indisputably—that
the problem has no true solution.
That's not to say computers cannot
communicate with each other
reliably, but 100% certainty is not
possible. Best efforts simply make
communication very very reliable
but never foolproof.”

PROOF OF WORK IS THE ANSWER

Proof of Work and connect with BYZANTINE Generals

Hash function takes an input
and returns a fixed-size
alphanumeric string.

ATTACK MONDAY HASH
8cd65c330ce4d0c58a45e676c2d08f0ddca6
c61f3b0a927ade10368d2d5aae6e

THE CONDITION IS THAT
THE PREFIX OF THE
OUTPUT HASH SHOULD
BE SUCH THAT THE HASH IS
PREFIXED BY 7 ‘0’s

ATTACK MONDAY HASH
0000000d1a2ea819ed13742fe7
386a34c25bb48e99b1ba8327c3
9551f6da5c01f98

ATTACK MONDAY HASH
8cd65c330ce4d0c58a45e676c2d08f0d
dca6c61f3b0a927ade10368d2d5aae6e
0000000d1a2ea819ed13742fe7386a34c25
bb48e99b1ba8327c39551f6da5c01f98
NONCE : 61584

NONCE CANNOT BE
CALCULATED BY A
FORMULA,
IT CAN ONLY BE GUESSED

DIFFICULT TO CALCULATE
EASY TO VERIFY

MESSAGE GOES WITH NONCE
ARMY 1 ARMY 2
ENEMY FORT TO BE
ATTACKED

MESSAGE VERIFIED WITH NONCE
ARMY 1 ARMY 2
ENEMY FORT TO BE
ATTACKED

MESSENGER RETURNS & CONFIRMS
ARMY 1 ARMY 2
ENEMY FORT TO BE
ATTACKED

CONSENSUS REACHED TO ATTACK AT
A COMMON TIME
ARMY 1 ARMY 2
ENEMY FORT TO BE
ATTACKED

But our STORY doesn't end here.

The town is now well aware of the
tricks that these generals are using, so
they simply purchase a giant
supercomputer and when they catch
a messenger they now have the
computing resources to modify the
nonce so that the seven ‘0’ s property is
satisfied.

FORT READY WITH
THAT MUCH COMPUTING
POWER

WE ADD MORE COMPUTING
REQUIREMENTS & MAKE IT
PRACTICALLY IMPOSSIBLE
FOR THE FORT TO SOLVE THE
NONCE

What's the connect with
BITCOIN CONSENSUS?

Let's now say that there is not
just two generals and one
city, but lots of generals and
lots of cities. Idea works
best when we have many,
many cities

https://www.reddit.com/r/Buttcoin/comments/4qa12v/byzantine_generals_proofofwork_for_d
ummies/ SOURCE

The generals all combine their many
messages into a SINGLE GIANT
MESSAGE (a "block") which gets but a
SINGLE NONCE at the end of it
SATOSHI'S IDEA IN A NUTSHELL

The new policy is that we need 16
ZEROs instead of only 7, so the hash
of that entire message comes out to
(say) 0000000000000000340291. That's a lot
of ZEROs!
INCREASE THE DIFFICULTY LEVEL

All Generals Take The Combined Message-
block and set all of their computers to go on
the great nonce hunt. Perhaps there are a
thousand armies, and each army has many
computers. Their combined efforts may find
a working nonce in a reasonable amount
of time.
And it only takes one of them finds the
nonce that satisfies the requirements:
once one finds it, they immediately share it
with all the others.

IS THEIR A QUESTION
WORRYING YOU?

IS THEIR A QUESTION
WORRYING YOU?
What if all of the cities bought
supercomputers and did the same thing
the generals did, team-up to find a
nonce?

Yes, they could do that, at
considerable expense. (Akin to the
"51% attack" — it works if the cities have
as much or more computing power as all
the armies combined.)
It's Not Impossible to Defeat this
scheme, but the generals have made
things very hard on attempts of the
cities by teaming up.

So here we are….THE PROOF OF
WORK…HOW IT WORKS FOR THE
BITCOIN?

RUSHED OVER OF A LOT OF CONCEPTS
Lot many
Dots
remain to
be
connected

https://www.reddit.com/r/Buttcoin/comm
ents/4qa12v/byzantine_generals_proofofw
ork_for_dummies/

anupamtiwari@protonmail.com
https://about.me/anupam.tiwari

Proof of Work and connect with BYZANTINE Generals

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Proof of Work and connect with BYZANTINE Generals