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Bitcoin and Cryptocurrencies Week 3 (Bitcoin Mechanics & Optimizations) (2)

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Signatures, ECDSA, and Addresses

DIGITAL SIGNATURE SCHEMES (DSS)

  • Alice uses ECDSA to generate private and public keys.
  • Bob needs Alice's public key.
  • Alice signs her message.
  • Alice sends message + signature. (The message is the main payload, and the signature can be used to prove that Alice was the one who created that exact message.)
  • Bob can easily verify if Alice signed.

 

암호화 알고리즘으로 ECC를 사용 ^^;


Bitcoin Script

Reminders :

  • Bitcoin uses a UTXO model
  • Transactions map inputs to outputs
  • Transactions contain signature of owner of funds
  • Spending Bitcoin is redeeming previous transaction outputs with a proof
    • Public Key + Signature in Pay-to-Pub-Key-Hash
    • Script + Signature in Pay-to-Script-Hash

 

Advanced Bitcoin Script

  • In Bitcoin, senders specify a locking script, recipients provide an unlocking script.
  • Pay-to-Pub-Key-Hash (P2PKH) : Vendor (recipient of transaction) says "Send your coins to the hash of this Public Key."
    • Simplest case
    • By far the most common case
  • Pay-to-Script-Hash(P2SH) : Vendor says "Send your coins to the hash of this Script"; I will provide the script and the data to make the script evaluate to true when I redeem the coins."
    • A vendor cannot say, "To pay me, write a complicated output script that will allow me to spend using multiple signatures."

TRANSACTION LOCKTIME

  • Extend bitcoin scripting into the dimension of time.
  • Absolute and relative timelocks
    • Absolute timelocks specify UNIX timestamp
    • Relative timelocks specify block height
  • Transaction-level and script-level timelocks
    • Transaction-level: the transaction itself will be postponed until the specified time
    • UTXO-level: the locking script restricts use of specific UTXOs

 

이 글은 edX의 Bitcoin and Cryptocurrencies 강의 자료를 참고하여 정리한 글입니다.

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