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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, […]
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 […]
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 = […]
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 […]
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 […]
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 […]
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 […]
Lecture 6: Bitcoin Miner interactions and Game Theory Game Theory: P x S -> R x P P: Players S: Strategies R: Rewards Examples For the prisoner’s dilemma, tit-for-tat with some positive randomization is the best strategy. Trench soldiers in […]
Lecture 5: Bitcoin mining How to mine Bitcoin Download and run Bitcoin-core to run full Bitcoin node Listen for a new transaction, assemble a pre-block Solve the puzzle (~270 attempts) Broadcast the block Profit The network runs on port 8333. Non-responding […]
Lecture 4: Blockchains 80 bytes block consists of 32 bytes previous block hash, 32 bytes transactions Merkle tree hash, timestamp, bits, nonce, etc. Each block is <= 1MB to minimize the propagation times. Therefore, large transactions require more service fee […]