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Lecture


Account Model vs UTXOs

  • Compare and contract the account model with the UTXO model which was popularized with Bitcoin.





Slides

Google Sheets Link


Ch1.4 Overview

Account Model vs UTXO Model

Account model (Ethereum) :

  • A global mapping of accounts -> balances
  • Sends reduce one account’s balance and increase another account's balance
  • Easy to understand
  • Easy to count and measure (wallets, dApps, etc...)
  • Allows for double spends and replay attacks if you're not careful

UTXO model (Bitcoin)

  • Every send must include the entire account balance.
  • Sends can specify multiple recipients.
  • Sends can originate from multiple senders.
  • Transactions depend on a specific set of unspent outputs (thus double spends are impossible because once spent there's new UTXOs and old ones are invalid)
  • Because double spends are impossible and dependencies are explicit, ordering does not matter so transactions can be processed in parallel
  • Can be complex to create wallets and infrastructure around this architecture

Neither the Account model or the UTXOs model are privacy preserving on their own! Just because the numbers/letters of addresses look funny to you does not mean that a computer programmer, crypto-currency exchange, or data scientist can't trace blockchain addresses to real world identities. The only purely private way to send transactions is with a cryptocurrency that uses zero knowledge proofs like (zcash).

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Last updated on 9/3/2019 by burrrata
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