Bitcoin: the most pertinent aspects in a computer science perspective

Hugues Bersini Jérémie Dubois-Lacoste

IRIDIA/ULB

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Intro: My three favourite aspects

1. Distributed – Decentralized – No intermediation

2. Incorruptible - Invulnerable3. Transparent and collaborative

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1/ Decentralized/Distributed

The wisdom of crowds

A blockchain

even in case the nodes are not trustful , aconsensus network no trust is required

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Decentralized

• Ideological • More robustness ( Internet at its birth)• Less control -> less authority (From Napster to

KazaA) -> less power exercice.• More division of labour : Wikipedia, Uber• More benefits sharing – Less richness

concentration (despite Google)

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2/Incorruptible : authentification + inalterability

public key private key

Cryptography is not for dissimulation

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Invulnerable

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Impossible to pay twice with the same money since it is very hard to create a tricky chain on

your own

You need to defeat the whole network

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Reward for mining

Proof of work It is cheaper to be honnestIt is better to mine than to fraud !

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3/ Transparent - Collaborative

• The bitcoin is open source. Any one can collaborate

• The block chain is transparent. Any one can have access.

• You would need a large coalition of cheaters to beat the system.

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Conclusions

• Bitcoin is a wonderful achievement in terms of IT (« it is a technological tour de force » – Bill Gates)

• It is IT at its very best• So it remains rather complex (to understand not to use)!• Cryptography, decentralisation, GPU (ASIC)• Decentralized vs centralized !!!!!!!!!!• The network is honnest though the nodes might not be• It goes not without ideology ( “I’m a big fan of bitcoin -

Regulation of money supply needs to be depoliticized” – Al Gore)