# The 1.x Files: A Primer for the Witness Specification

DevFeed: [The 1.x Files: A Primer for the Witness Specification](<https://devfeed.tech/articles/the-1-x-files-a-primer-for-the-witness-specification-16901.md>)

Original publisher: [Read original article](<https://blog.ethereum.org/en/2020/05/04/eth1x-witness-primer>)

Author: Griffin Ichiba Hotchkiss

Published: 2020-05-04T00:00:00Z

Content type: tutorial

Language: en

Sources: [Ethereum Foundation Blog](<https://devfeed.tech/sources/ethereum-foundation-blog.md>)

Topics: [Ethereum](<https://devfeed.tech/topics/ethereum.md>), [Blockchain](<https://devfeed.tech/topics/blockchain.md>), [Data structures](<https://devfeed.tech/topics/data-structures.md>), [Code](<https://devfeed.tech/topics/code.md>)

Tags: [blockchain](<https://devfeed.tech/tags/blockchain.md>), [canonical](<https://devfeed.tech/tags/canonical.md>), [consensus](<https://devfeed.tech/tags/consensus.md>), [data-structure](<https://devfeed.tech/tags/data-structure.md>), [ethereum](<https://devfeed.tech/tags/ethereum.md>), [hashing](<https://devfeed.tech/tags/hashing.md>), [research-development](<https://devfeed.tech/tags/research-development.md>)

## AI overview

This primer explains the formal Witness Specification as part of the Stateless Ethereum effort. It introduces Ethereum state, including accounts, balances, smart-contract code and memory, and describes how the state is represented by a Merkle-Patricia Trie whose root hash can be used for verification.

## Source excerpt

Since a lot of us have a bit more time on our hands, I thought now might be a good opportunity to proceed with something perhaps a little bit boring and tedious, but nevertheless quite fundamental to the Stateless Ethereum effort: understanding the formal Witness Specification. Like the captain...