What is EVM

Understanding Ethereum Virtual Machine (EVM)

The Ethereum Virtual Machine (EVM) serves as the backbone for Ethereum’s decentralized ecosystem, orchestrating the continuous and immutable operation of a distributed state machine. This intricate system, maintained by thousands of connected computers, defines the rules for computing a new valid state from block to block.

Key Concepts

1. Canonical State: At any given block, Ethereum maintains a single ‘canonical’ state, governed by the EVM, which encapsulates all Ethereum accounts and smart contracts.

2. Prerequisites: Understanding EVM requires familiarity with computer science terminology like bytes, memory, and a stack, as well as knowledge of cryptographic and blockchain concepts such as hash functions and Merkle trees.

3. From Ledger to State Machine: Unlike Bitcoin’s distributed ledger, Ethereum operates as a distributed state machine. Its state includes accounts, balances, and a dynamic machine state, changing according to predefined rules and capable of executing arbitrary machine code.

4. Ethereum State Transition Function: Described as a mathematical function, the EVM produces a deterministic output (new state) given an old valid state and a set of valid transactions.

5. Transactions: Cryptographically signed instructions from accounts, transactions can result in message calls or contract creation. Smart contract bytecode executes when called by another account.

6. EVM Instructions: The EVM functions as a stack machine with 1024 items, each a 256-bit word. It executes bytecode using various opcodes for stack operations and blockchain-specific functions.

EVM Implementations

– Over Ethereum’s history, the EVM has seen revisions, and there are implementations in various programming languages.
– Examples include Py-EVM (Python), evmone (C++), ethereumjs-vm (JavaScript), eEVM (C++), and revm (Rust).

Understanding the EVM is essential for comprehending Ethereum’s inner workings, enabling the execution of smart contracts and maintaining the integrity of the blockchain.

Source: Ethereum.org