◦ The Cypherpunks Mailing List ◦ release of The Cyphernomicon (1994) ◦ missions including protection of privacy using encryption ◦ crypto-anarchism • 1998: b-money ◦ Wei Dai ◦ b-money, an anonymous, distributed electronic cash system ◦ base of future blockchains: proof of work, transactions, broadcast • 2005: bit gold ◦ Nick Szabo ◦ Bit Gold: Towards Trust-Independent Digital Money 5
much speculation ◦ massive loss of money for people ◦ some banks were definitely closed ◦ some banks were nationalized ◦ loss of confidence to usual financial systems • 2008: Bitcoin ◦ Satoshi Nakamoto ◦ Bitcoin: A Peer to Peer Electronic Cash System ◦ birth of the 1st cryptocurrency! 6
• each transaction has a cost (Tx fees) • transactions are stored inside a pool before being added • Tx fees order the transactions 13 Number of BTC transactions in pool (10/30/2018) bitcointicker.co
problem to choose the one who will add the block and trigger the transactions stored inside • challenge = consensus ◦ Proof Of Work ◦ Proof of Stake ◦ Proof of Authority ◦ Proof of Importance ◦ ... 16 ? ? ? ? ?
block with ◦ hash of previous block ◦ hashtree root for tx ◦ difficulty ◦ ... 1. find the golden nonce, i.e. the random value with makes the block hash lower than the difficulty ➔ brute force! 17 Blockchain Bitcoin Ethereum Monero Dogecoin Difficulty 7 184 404 942 702 2 986 685 821 724 284 61 820 335 411 2 716 801 Block time 10’50’’ 14.3’’ 2’2’’ 1’2’’ • 11/07/2018 • bitinfocharts.com hash n-1 hash algorithm hash n nonce
of the previous block (hash) • each block has a fingerprint of the previous block (hash) hash n-1 hash n hash n-2 bloc n - 1 bloc n bloc n + 1 hash hash
the previous block (hash) 21 hash n-1 hash n hash n-2 bloc n - 1 bloc n bloc n + 1 hash hash • each block has a fingerprint of the previous block (hash) • to corrupt a block, we must modify all the following blocks • a strong protocol is applied to check the blockchain and ensure its integrity hash of corrupted block
node of the network • if we want to corrupt a blockchain, we have to corrupt all blockchains before the next update • this kind of attack implies too much energy and computational power 22 full node lite node
implemented by a lot of cryptocurrencies • looks like fiat currencies • can be sliced into smaller fragments ERC 721 • not fungible (= unique) • cannot be sliced • “manufactured collectible” 27
value • for financial transactions • real cryptocurrencies security/equity tokens • represent assets • can be seen like securities, derivatives, ... • used in ICO 28 utility tokens • provided access to services • dedicated for use cases
• hack of TheDAO • ~ 3 600 000 stolen ETH (~ 70 000 000 USD at the time) • → hard fork to cancel the theft (Ethereum) • a part of the community refused • = birth of Ethereum Classic (no fork)
of BTC blockchains with SegWit to increase speed of transactions and blocks sizes • → contentions in community • = hardfork (07/2017) giving birth to Bitcoin Cash • need to mine bitcoins without ASIC • = hardfork (10/2017) giving birth to Bitcoin Gold
• November 2018 • a civil war between two camps... • conflict between rich people about vision, control, influence (and also block sizes) • Craig Wright vs Roger Ver (and the rest of the world) • hashwar to get rid of the opponents • = hardfork splitting Bitcoin Cash to Bitcoin ABC and Bitcoin SV
address is protected (Stealth Addresses) • transaction balance is protected (Ring Confidential Transactions) • broadcast of transactions is protected (Kovri) • XMR balances not related to public addresses “secure, private, untraceable” (today) 36
not (t-addr) • z-addr are protected with a Non Interactive Zero Knowledge Proof method (zk-SNARK) • public blockchain but private project driven by the Zerocoin Electric Coin Company Snowden approved 38
• hosted on Ethereum • 1 BAT = 0.33 USD • created by Brendan Eich • integrated to Brave browser • designed to value and price humain attention (for fair ads) • 30’’ to raise 35 millions USD during the ICO
Ethereum • 1 CO2 = 3.81 USD • trade the carbon using tokens • try to build a “blockchain green ecosystem” (not a joke) Climatecoin Save the planet, trade the carbon
Buterin ◦ was only 19 y.o.! • blockchains are: ◦ decentralized ◦ replicated (distributed) ◦ not regulated ◦ use tokens ◦ have blocks with financial transactions • and what if we put programs in blockchains? ◦ Ðecentralized applications The Ethereum Experience 44
Ethereum Virtual Machine (EVM) • transactions have bytecode in payload • execution of programs are conditioned ◦ tokens are used to process instructions ▪ ETH, ETC, ... ◦ each instruction has a cost ▪ gas • nodes of network check outputs of programs • Ethereum can be seen as kind of “slow” database/register • Ethereum Yellow Paper • Gas Costs from Yellow Paper
to evaluate: ◦ costs of instructions ◦ fees of transactions (TxFees) ◦ value of transactions earned by miners final cost of the transaction, earned by miner wei = unit for gas the amount of gas to burn to process the program of the smart contract, which depends to the amount of code to process • the lower the price is, the less gainful the transaction is, the later the transaction will be mined • allow to involve the cost of the transaction
1 computer processing series of N instructions ◦ parallel ➞ 1 computer processing K (in N) instructions at the same time (threads) ◦ distributed ➞ X computers processing samples of the N instructions • Decentralized paradigms • X computers processing at the same time the N instructions • programs are duplicated in computers • no more unique server or backend which hosts the program →no authorities to trust →no centralisation to fail →but slower than centralized solutions
web server smart contract sources (.sol) smart contract ABI (.js, .json) web app (.html, .css, .js, ...) hosting compilation inclusion deployment web browser
and unique address • the code is law • hosted in the blockchain • once deployed, cannot be ◦ removed ◦ modified • if bugs or flaws appear ◦ write a new contract! 51 More about smart contracts ÐApps on Ethereum with Solidity
be optimized ◦ choose the best functions ◦ be aware with storage of data ◦ use the most suitable data types ◦ decrease complexity of functions • If the program is: ◦ dirty ◦ heavy ◦ not enough well written ➔ may burn a lot of gas ➔ must be expensive in Ether
products tracking ◦ e.g. IBM Food Trust ◦ e.g. Connecting Food • fight against censorship, fake news... ◦ e.g. PUBLIQ • citizenship ◦ e.g. online vote using blockchains • insurance ◦ e.g Etherisc • documents and securities transfer, ...
e.g Algeria, Bolivia, China, Ecuador, Egypt, Iran, Morocco • more or less regulated ◦ e.g Canada, France, Singapore, USA • supported ◦ e.g Estonia, Japan • used for national cryptocurrencies ◦ e.g Estonia (Estcoin?), Venezuela (Petro)
• may be censored, controlled or regulated by governments • are occulted by the hype around Bitcoin (-_-)” • enhance and boost innovations and technical challenges (ﾉ^_^)ﾉ we can think using a new framework: decentralization
Know bout, Daly Bit • A 101 Noob Intro to Programming Smart Contracts on Ethereum, ConsenSys • Basic Attention Token, basicattentiontoken.org • Basic Attention Token (BAT), Brave Software • Bitcoin: A Peer-to-Peer Electronic Cash System, Satoshi Nakamoto • Bitcoin: The Cryptoanarchists’ Answer to Cash, Morgen E. Peck • Bitcoin Cash’s ‘Mining War’ Escalates as Blockchain Hard Fork Approaches, Nikhilesh De • Bitcoin Is Terrible for the Environment, Emily Atkin • Bit Gold and Bitcoin, In Search Of Satoshi • Bloc Genesis, bitcoin.fr • Blockchain Security Mechanisms, Shaan Ray • Climatecoin, climatecoin.io • Create Your Own Crypto-currency with Ethereum, ethereum.org • Crossing Over to Web3 - An Introduction to Decentralised Development, Luke Hedger • CryptoKitties, cryptokitties.co • Cryptomonnaies - mode d’emploi en 20’, Pierre-Yves Lapersonne • ÐApps on Ethereum with Solidity, Pierre-Yves Lapersonne • Decentraland, decentraland.org • Demystifying Hashgraph: Benefits and Challenges, Yaoqi Jia • Ethash, github.com/ethereum Web sites visited on 11/23/2018
• Ethereum: Ether, Ether Gas, Gas Limit, Gas Price & Fees [...], Sudhir Khatwani • Ethereum “Gas” - How it works, steemit.com • Everything You Need to Know About [...] Sapling Upgrade [...], John Westbrook • Full-stack smart contract development, Júlio Santos • Hashgraph wants to give you the benefits of blockchain without the limitations, Samantha Stein • Hedera Hashgraph, hederahashgraph.com • How to build your own Ethereum based ERC20 Token and launch an ICO in next 20 minutes, Sandeep Panda • Hyperledger, hyperledger.org • Introduction to Smart Contracts, solidity.readthedocs.io • Kovri, getkovri.rg • La Révolution des Blockchains, Pierre-Yves Lapersonne • Ledger Legends, ledgerlegends.com • Les bitcoins dans les bureaux de tabac, une information fumeuse, Maxime Vaudano & Pierre Breteau • Les cryptomonnaies sont-elle halal ?, Gregory Raymond • Multisignature, en.bitcoin.it • Proof of Work vs Proof of Stake: Basic Mining Guide, blockgeeks.com • Reversing EVM bytecode with radare2, Fedor Sakharov • Ring Confidential Transactions, Shen noether, Adam Mackenzie and Monero Core Team • Ring signature, wikipedia.org Web sites visited on 11/23/2018
Systems, N. Courtois, R. Mercer • Swarm, swarm-guide.readthedocs.io • The Cyphernomicon, nakamotoinstitute.org • The Ethereum Experience, Ethereum • The Next Generation of Distributed Ledger Technology, iota.org • The Story of the DAO - Its History and Consequences, Samuel Falkon • The Tangle, Serguei Popov • The Tangle: an Illustrated Introduction, Alon Gal • Types of Consensus Protocols Used in Blockchains, Evan Tan • Types of tokens. The four mistakes beginner crypto-investors make, ICOscoring • Understanding Blockchain Fundamentals, Part 1: Byzantine Fault Tolerance, Georgios Konstantopoulos • Understanding Segregated Witness, Jimmy Song • Vie privée, telle est ma devise, Pierre-Yves Lapersonne • W-ETH, weth.io • Walking Through the ERC721 Full Implementation, Karen Scarbrough • WBTC, www.wbtc.network • What are Sidechains?, Shaan Ray • When I say mine you say Coinhive, Pierre-Yves Lapersonne • Whisper, github.com/ethereum Web sites visited on 11/23/2018
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