Bitcoin introduction at Bizcamp Ghent June 11th 2011 (http://bizcamp.be/).

• I have tried to explain bitcoin with the following metaphors:– a cash register copied over the hard drives of all participants– public/private keys as coloured pens: a transaction is only valid if it is written in the color of the

pen that is writing the transaction in the register (unlimited number of colours, none is the same) – bitcoin blocks as pages in the cash register– the node that first solves a sudoku puzzle made up of all the transactions in the page (and with the

puzzle on the previous page), gets 50 bitcoins as a prize (as a metaphor for mining, this one turned out the most difficult to grasp)

– the transaction history can't be falsified because that would require solving sudoku puzzles faster than the combined rest of the world

– economic value generated by mining is the stability of the system as a whole (transaction history not falsifiable)

• Rest of the screenshots:– how the client works– discussion of (relative) "anonymity”– driver behind current speculation: expectation that a sizeable amount of the underground

economy will move into bitcoin– Bitcoin mining hardware and business– risks and challenges for bitcoin

Bitcoin

a Peer-to-Peer Electronic Cash System

Transactions

Blue sends 3 to green

Blue sends 3

to

green

Blue

send

s 3 to

gree

n

Blue sends 3 to green

Blue sends 3 to green

Double-spending

Red sends 1.1 to green

Blue sends 3 to green

Grey sends 1 to red

Blue sends 3 to red

Red sends 1.1 to grey

Red sends 1.1 to green

Blue sends 3 to green

Grey sends 1 to red

Blue sends 3 to red

Red sends 1.1 to grey

I have a page with transactions for which I have solved a Sudoku

puzzle!

Red sends 1.1 to green

Blue sends 3 to green

Grey sends 1 to red

Blue sends 3 to red

Red sends 1.1 to grey

Red gets 50 for the puzzle!

Red sends 1.1 to green

Blue sends 3 to green

Grey sends 1 to red

Blue sends 3 to red

Red sends 1.1 to grey

Red gets 50 for the puzzle!

Blue sends 4 to green

…

Difficulty

Bitcoin mining

Fees

Blockchain and block size

Future?

?