Dive Deeper into The Ethereum Virtual Machine (EVM)
A Decentralized Computer for dApps
The Ethereum Virtual Machine (EVM) is a Turing-complete, decentralized computer that runs on every node in the Ethereum network. It is responsible for executing smart contracts, which are self-executing contracts that are stored on the blockchain.
The EVM is a significant innovation in blockchain technology because it allows developers to create decentralized applications (dApps) that can be used without the need for a central authority. This makes dApps more secure, transparent, and efficient than traditional applications.
The EVM's Role in Ethereum
The Ethereum network is often described as a global computer, with the EVM serving as its central processing unit (CPU). The EVM's primary function is to execute smart contracts, which are written in high-level programming languages like Solidity and compiled into bytecode. The EVM interprets and executes this bytecode in a secure and deterministic manner, ensuring that the outcome of a smart contract's execution is the same across all nodes in the network.
The EVM is not a physical machine that can be pointed to like a cloud server or an ocean wave, but it does exist as a single entity maintained by thousands of connected computers running an Ethereum client. The Ethereum protocol exists solely to ensure the continuous, uninterrupted, and immutable operation of this unique state machine.
How does the EVM work?
The EVM works by executing smart contracts in sequential order. When a smart contract is submitted to the network, it is broken down into a series of instructions that are then executed by the EVM.
At its core, the EVM is a state machine that processes transactions and maintains the Ethereum network's state. The state of Ethereum is a large data structure called a modified Merkle Patricia Trie, which holds all accounts and balances, as well as the machine state.
The EVM defines the rules for computing a new valid state from block to block. The EVM operates as a stack machine with a depth of 1024 items, each being a 256-bit word. This design choice allows for easy integration with 256-bit cryptography, such as Keccak-256 hashes or secp256k1 signatures.
During execution, the EVM maintains a transient memory that does not persist between transactions. However, contracts do contain a Merkle Patricia storage trie associated with the account in question and part of the global state. Smart contracts are compiled into bytecode, which is then executed as a series of EVM opcodes. These opcodes perform standard stack operations like XOR, AND, ADD, SUB, etc., as well as blockchain-specific stack operations like ADDRESS, BALANCE, BLOCKHASH, and more
The EVM can be used to create a wide variety of dApps. Some of the most popular dApps include decentralized exchanges, lending platforms, and games.
Why is the EVM important?
The EVM is an important part of the Ethereum ecosystem because it allows developers to create dApps that can be used without the need for a central authority. This makes dApps more secure, transparent, and efficient than traditional applications.
The EVM is also important because it is a key part of the Ethereum scalability roadmap. As the Ethereum network grows, the EVM will be able to handle more transactions and more complex dApps.
EVM Implementations
All EVM implementations must adhere to the specifications outlined in the Ethereum Yellowpaper. Over Ethereum's history, the EVM has undergone several revisions, with multiple implementations in various programming languages.
Some popular standalone implementations include:
1. Py-EVM - Python
2. evmone - C++
3. ethereumjs-vm - JavaScript
4. eEVM - C++
These implementations are used in Ethereum execution clients and help maintain the network's decentralized nature.
Transactions and Contract Creation
Transactions in Ethereum have cryptographically signed instructions from accounts. There are two types of transactions: message calls and contract creations. When a contract is created, a new contract account is generated, containing compiled smart contract bytecode. Whenever another account makes a message call to that contract, the EVM executes its bytecode.
What are the benefits of using the EVM?
There are many benefits to using the EVM, including:
Security: The EVM is a decentralized computer, which means that there is no single point of failure. This makes it more secure than traditional applications, which are often hosted on centralized servers.
Transparency: The EVM is a public blockchain, which means that all transactions and smart contract executions are visible to everyone. This makes it more transparent than traditional applications, which are often closed source.
Efficiency: The EVM is a Turing-complete computer, which means that it can be used to create any type of dApp. This makes it more efficient than traditional applications, which are often limited by the capabilities of the underlying platform.
What are the challenges of using the EVM?
There are a few challenges to using the EVM, including:
Complexity: The EVM is a complex piece of technology, which can make it difficult to develop dApps.
Cost: The EVM uses gas, which is a fee that is paid to miners for executing smart contracts. This can make dApps more expensive than traditional applications.
Security: The EVM is a decentralized computer, which means that it is vulnerable to attack. This is a risk that developers must be aware of when creating dApps.
The Ethereum Virtual Machine (EVM) is a powerful tool that can be used to create a wide variety of dApps. The EVM is secure, transparent, and efficient, and it is a key part of the Ethereum ecosystem. However, the EVM is also complex and expensive, and developers must be aware of the security risks before creating dApps.