Stanford CS251: Lecture 16
Lecture 16: Bitcoin payment channel Visa ~ 10, 000 transactions per second Bitcoin ~ 3 transactions per second => 60 GB of blockchain data per year Waiting for 6 blocks ~ 60 mins is a huge wait for Bitcoin. Therefore, […]
Stanford CS251: Lecture 15
Lecture 15: Bitcoin guest talk (Greg Maxwell & Pieter Wuille – Blockstream) on sidechains Forking does not advance Bitcoin since forks suffer from economic acceptance. UTXO model UTXO model is less intuitive, more private, and smaller persistent storage footprint. UTXO […]
Stanford CS251: Lecture 13
Lecture 13: Ethereum Code: ROM (Read-only memory) calldata: arguments There are two types of instructions: Arithmetic including SHA3 and sys operations like create [contract], call [contract], and delegate call, etc. CALL – called code is executed in the context of […]
Stanford CS251: Lecture 14
Lecture 14: Ethereum Governance When contracts call other contracts, there are four major parameters, g – gas, v – value, in – in size of inputs, out – out size of outputs. The gas must come from the initial transaction, […]
Stanford CS251: Lecture 12
Recap: alt-coins Bitcoin is a replicated state machine, the system moves within S States with I inputs producing O outputs. For Bitcoin, S is the set of UTXOs. For Namecoin, the state consists (name, value). Ethereum’s goal was to implement […]
Stanford CS251: Lecture 11
Lecture 11: Altcoins Three ways to improve Bitcoin Code update – This can update or change the P2P network Soft fork – To introduce a stricter verification for example P2SH Hard fork – transaction improvements and consensus change Altcoin = […]
Stanford CS251: Lecture 10
Lecture 10: Anonymity on Blockchain (Coinjoin continued from the previous lecture) Each participant writes an input transaction (input address, change address) on say Pastebin. Over Tor, each participant writes an output address. These two entries and not linkable to each […]
Stanford CS251: Lecture 9
Lecture 9: Wallet & Anonymity Wallet A user has a lot of bitcoin address, each of which is H(p_k) or H(script). A wallet manages p_k/s_k, post/verify transactions, and show balances. A wallet can be Cloud wallets like Coinbase or desktop […]
Stanford CS251: Lecture 8
Lecture 8 – Alternative consensus Puzzle solutions are probabilistic proof of work. A typical puzzle utilization function can be modeled as P(challenge, randomness – nonce, difficulty, …) -> true/false P(c, r, d) for Bitcoin is SHA256^2(c, r, d) <= 2^256-d […]
Stanford CS251: Lecture 7
Lecture 7: Community, Economics, and Politics David Chaum – digital cash in 1981 Satoshi Nakamoto – Oct 2008, bitcoin.org was registered in Aug 2008 Genesis block was mined in Jan 2009 First BTC payment – Feb 2010 First online exchange […]