Written by Jeff Kuan
Segregated Witness ("Seg-Wit") was a protocol upgrade activated as a soft fork on the Litecoin blockchain on May 10, 2017, and on the bitcoin blockchain on August 23, 2017.
The upgrade was originally intended to fix a bug in the bitcoin code called transaction malleability, which allowed anyone to change details that modified the transaction ID. The SegWit upgrade fixed transaction malleability by removing the signature (“witness”) information from transactions and storing it outside the transaction block. Without this signature information, block size is reduced, and therefore allows a much larger number of transactions to be processed per block.
SegWit also enabled the development of more complex features on the blockchain, such as second-layer protocols and smart contracts. Resistance to SegWit as a scaling solution was one of the factors that led to the development of Bitcoin Cash, a hard fork of the Bitcoin blockchain.
SegWit, Explained by Andrew Marshall
What is SegWit? by Noelle Acheson
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