Golden
Segregated Witness (SegWit)

Segregated Witness (SegWit)

Segregated witness, or SegWit, is an update to blockchain protocols in which the digital signatures are separated from the transaction data in the blocks. It is the name used for a soft fork change in the transaction format of the cryptocurrencies Bitcoin, Litecoin, and others.

Segregated Witness (SegWit) is a blockchain protocol change that separates scripts and signatures into a new structure that is committed to blocks in the blockchain apart from other transaction data. This effectively compartmentalizes data that is needed to validate the blockchain state away from data that is necessary to actually determine the effects of transactions.



There are four main motivations for implementing SegWit on a blockchain protocol such as Bitcoin:

  1. Prevent nonintentional transaction malleability
  2. Improve the speed of transaction propagation
  3. Bypass existing blockchain constraints such as block size limitations in order to improve scalability
  4. Allow for the inclusion of data required for fraud proofs



Additionally, the transaction malleability fix allows for the creation of unconfirmed transaction dependency chains without counterparty risk, which is necessary in order to implement trustless layer 2 solutions such as the Lightning Network. SegWit itself is not necessary for the Lightning Network to work, but a transaction malleability fix of some kind is necessary. Other solutions for the malleability issue have been proposed such as Flexible Transactions.

SegWit Activation

SegWit first went live in a soft fork of the Bitcoin blockchain on August 23, 2017. A hard fork named SegWit2x that would force all miners to activate SegWit was scheduled for November 17, 2017. However, the fork was socially contentious and ultimately didn't garner enough support for the new cryptocurrency (B2X) to be relevant compared to BTC.



Timeline

People

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Related Golden topics

Peter Wuille





Further reading

Title
Author
Link
Type
Date

Bitcoin Legal Experts: nChain SegWit Criticisms Are Flawed - CoinDesk

Pete Rizzo

Web



Is segregated witness necessary to implement the Lightning Network?

SegWit Resources

Web



The Long Road to SegWit: How Bitcoin's Biggest Protocol Upgrade Became Reality

Aaron van Wirdum

Web



The Risks of Segregated Witness: Possible Problems Under US Contract Law - CoinDesk

Jimmy Nguyen

Web



Documentaries, videos and podcasts

Title
Date
Link

Bitcoin Q&A: What is Segregated Witness?

April 28th, 2018

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