Ethereum is a decentralized computing platform. Imagine it like a laptop or desktop computer, but it doesn't run on a single device. Instead, it operates simultaneously on thousands of machines worldwide, meaning it has no single owner.
Like Bitcoin and other cryptocurrencies, Ethereum allows you to transfer digital money. However, it's capable of much more. You can deploy your own code and interact with applications created by other users. This flexibility enables all kinds of sophisticated programs to be launched on Ethereum.
Understanding Ethereum Basics
At its core, Ethereum enables developers to create and publish code that runs on a distributed network instead of a centralized server. This means that, in theory, these applications cannot be stopped or censored.
It's important to clarify terminology: the units used on Ethereum aren't called "Ethereum" or "Ethereums." Ethereum refers to the protocol itself, while the currency that powers it is simply called ether (ETH).
The Value of Ethereum
What makes Ethereum valuable is its ability to execute code through a distributed system. Programs added to Ethereum's database (the blockchain) can be programmed to be uneditable. Since everyone can view the database, users can audit code before interacting with it.
This means anyone, anywhere can launch applications that cannot be taken offline. Even more interestingly, because its native unit—ether—is a store of value, these applications can establish conditions for how value is transferred.
These programmable applications are called smart contracts. In most cases, they can be configured to operate without human intervention. The concept of "programmable money" has captivated users, developers, and businesses worldwide.
Blockchain Technology Explained
The blockchain is a fundamental component of Ethereum—it's the database containing information used by the protocol. If you're familiar with Bitcoin, you'll have a basic understanding of how blockchain works.
Think of Ethereum's blockchain as a book where you keep adding pages. Each page is called a block, filled with transaction information. When adding a new page, a special value must be included at the top that allows anyone to verify that the new page was added after the previous one, not randomly inserted into the book.
This process uses hashing, which takes data (everything on our page) and returns a unique identifier (our hash). The probability of two different datasets producing the same hash is astronomically low. Hashing is a one-way process: easy to compute a hash but virtually impossible to reverse it to obtain the original information.
Ethereum vs. Bitcoin: Key Differences
Bitcoin relies on blockchain technology and financial incentives to create a global digital cash system. It introduced key innovations that enable worldwide user coordination without central representatives. Bitcoin is often described as a first-generation blockchain—it wasn't designed to be overly complex, which contributes to its security strength.
Second-generation blockchains like Ethereum can do more. Besides financial transactions, these platforms allow for greater programmability. Ethereum gives developers more freedom to experiment with their code and create what we call Decentralized Applications (DApps).
While Ethereum shares similarities with Bitcoin and can perform many of the same functions, the two are fundamentally different—each with advantages over the other.
How Ethereum Works
Ethereum can be defined as a "state machine." This means that at any given moment, you have access to a snapshot of all account balances and smart contracts in their current state. Certain actions trigger state updates, meaning all nodes update their snapshots to reflect changes.
Smart contracts running on Ethereum are triggered by transactions from users or other contracts. When a user sends a transaction to a contract, every node on the network executes the contract's code and records the output. This is done using the Ethereum Virtual Machine (EVM), which converts smart contracts into instructions computers can understand.
To update the state, Ethereum currently uses a special mechanism called mining, conducted through a Proof of Work algorithm similar to Bitcoin's.
Understanding Smart Contracts
A smart contract is simply code—it's neither "smart" in the traditional sense nor a "contract" in the legal sense. The term "smart" refers to execution under certain conditions, and "contract" refers to the enforcement of agreements between parties.
The original concept can be attributed to computer scientist Nick Szabo, who proposed it in the late 1990s. He used a vending machine as an example of a precursor to modern smart contracts. With a vending machine, users insert coins and receive their selected product in return.
Smart contracts apply this logic in a digital environment. You could specify something simple in code like: "return 'Hello, World!' when two ethers are sent to this contract."
In Ethereum, developers program this code to be interpreted by the EVM, then publish it by sending it to a special address that registers the contract. Once deployed, anyone can use it. Notably, contracts cannot be deleted unless the developer specified a condition for deletion during programming.
The contract receives an address, and users only need to send 2 ETH to that address to interact with it. This activates the contract's code—all computers on the network execute it, verify payment, and record the output ("Hello, World!"). More sophisticated applications connecting multiple contracts can be—and have been—created.
The Creation of Ethereum
In 2008, an unknown developer (or group) published the Bitcoin whitepaper under the pseudonym Satoshi Nakamoto. This event permanently transformed the digital money landscape. A few years later, a young developer named Vitalik Buterin conceived a way to further develop this idea and apply it to any type of application.
Buterin proposed Ethereum in 2013 in a blog post titled "Ethereum: The Ultimate Smart Contract and Decentralized Application Platform." He described the idea of a Turing-complete blockchain—a decentralized computer that, given enough time and resources, could run any application.
The types of applications that could be deployed on the blockchain would be limited only by developers' imaginations. Ethereum aims to explore whether blockchain technology has valid uses beyond Bitcoin's deliberately limited design.
Ethereum launched in 2015 with an initial money supply of 72 million ether. Over 50 million tokens were distributed in a public token sale called an Initial Coin Offering (ICO), allowing interested participants to purchase ether tokens using bitcoin or fiat currency.
The DAO and Ethereum Classic
With Ethereum, completely new forms of open collaboration on the Internet became possible. Consider DAOs (Decentralized Autonomous Organizations), which are entities governed by computer code.
One of the first and most ambitious attempts to implement such an organization was "The DAO," which was supposed to consist of complex smart contracts running on Ethereum and function as an autonomous venture capital fund. DAO tokens were distributed in an ICO, granting ownership shares and voting rights to holders.
Shortly after launch, however, malicious actors exploited a vulnerability and drained nearly one-third of The DAO's funds. At the time, approximately 14% of all ether supply was locked in The DAO, making this a devastating event for the still-nascent Ethereum network.
After deliberation, the community decided to execute a hard fork on the blockchain, resulting in two chains. On one chain, the malicious transactions were effectively reversed to restore funds—this chain is now known as the Ethereum blockchain. The original chain, where these transactions weren't reversed and immutability was maintained, is now known as Ethereum Classic.
This event served as a severe reminder of the risks of this technology and that trusting large amounts of money to autonomous code can be counterproductive. It also illustrated the challenges of collective decision-making in an open environment. Despite its security vulnerabilities, The DAO perfectly demonstrated smart contracts' potential to facilitate large-scale, trustless collaborations on the Internet.
Frequently Asked Questions
What's the difference between Ethereum and ether (ETH)?
Ethereum refers to the protocol and network itself, while ether (ETH) is the native cryptocurrency that powers the network. ETH is used to pay for transaction fees and computational services on the Ethereum network.
How is new ether created?
New ether is created through the mining process, where miners validate transactions and create new blocks. Currently, miners receive 2 ETH as a block reward plus transaction fees. This system will change with Ethereum's transition to Proof of Stake.
What are gas fees in Ethereum?
Gas fees are payments made by users to compensate for the computing energy required to process and validate transactions on the Ethereum network. Gas prices fluctuate based on network demand, measured in gwei (1 gwei = 0.000000001 ETH).
Can Ethereum transactions be reversed?
Generally, Ethereum transactions are irreversible once confirmed on the blockchain. The 2016 DAO hack resulted in an exceptional hard fork that reversed transactions, but this was an extreme measure in response to extraordinary circumstances and not the norm.
What are Ethereum tokens?
Ethereum tokens are digital assets created on the Ethereum blockchain using smart contracts. The most common standard is ERC-20, which allows developers to create fungible tokens with specific parameters for supply, divisibility, and other characteristics.
How does Ethereum differ from Bitcoin?
While both are cryptocurrencies, Ethereum is fundamentally a programmable blockchain that enables smart contracts and decentralized applications, whereas Bitcoin was primarily designed as a digital currency and store of value.
Ethereum Mining and Network Participation
Mining is critical for Ethereum's network security. It ensures the blockchain can be updated fairly and allows the network to operate without central management. In mining, a subset of nodes (appropriately called "miners") dedicate computational power to solving cryptographic puzzles.
Miners hash a set of pending transactions along with other data. For a block to be considered valid, the hash must fall below a value determined by the protocol. If unsuccessful, they can modify some data and try again.
To compete, miners need to hash as quickly as possible—their power is measured as hash rate. The higher a network's hash rate, the more difficult puzzle-solving becomes. Only miners need to find the solution—once known, it's easy for other participants to verify its validity.
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Mining at high speeds constantly is expensive. To incentivize miners to protect the network, they earn rewards consisting of transaction fees from the block plus newly generated ether—currently 2 ETH at the time of writing.
Gas and Transaction Costs
Remember our "Hello, World!" contract example? It was an easy program to execute, not computationally expensive. However, you're not running it just on your own PC—you're asking everyone in the Ethereum ecosystem to run it too.
This raises an important question: What happens when tens of thousands of people run sophisticated contracts? If someone configures their contract to loop the same code continuously, every node would be forced to execute it indefinitely. This would place excessive pressure on available resources, eventually crashing the system.
Fortunately, Ethereum introduces the concept of gas to mitigate this risk. Just as your car can't run without gasoline, contracts can't execute without gas. Contracts establish how much gas users must pay to execute them successfully. Without sufficient gas, the contract stops.
This mechanism acts as a fee system. The same concept applies to transactions: miners are primarily motivated by profits, so they may ignore transactions with lower fees.
Note that ether and gas are not the same. The average gas price fluctuates and is largely determined by miners. When you make a transaction, you pay for gas in ETH. In this sense, it resembles Bitcoin fees—if the network is congested with many users trying to transact, the average gas price will likely increase. Conversely, it will decrease when there's less activity.
Although gas prices vary, each operation requires a fixed amount of gas. Complex contracts consume much more gas than simple transactions. Therefore, gas is a measure of computational power. It ensures the system can charge users appropriate fees based on their use of Ethereum's resources.
Gas typically costs a fraction of ether, so we use a smaller unit (gwei) to designate it. One gwei equals one billionth of an ether (0.000000001 ETH).
In summary, you could run a program in a loop for an extended period, but doing so would become very expensive very quickly. This mechanism allows Ethereum network nodes to mitigate spam.
Gas Limits and Transaction Processing
Suppose Alice wants to execute a transaction with a contract. She must calculate how much she wants to spend on gas. She can set a higher price to incentivize miners to include her transaction quickly.
She'll also specify a gas limit to protect herself. Something could go wrong with the contract, causing higher gas consumption than anticipated. The gas limit ensures that once a certain amount of gas is consumed, the operation will stop. The contract might fail, but Alice won't pay more than she initially agreed to pay.
While this might seem confusing initially, most wallets handle gas price and limit settings automatically. In summary: gas price determines how quickly miners will accept your transaction, while the gas limit sets the maximum you'll pay for it.
Block Times and Transaction Speed
The average time to add a new block to the chain is between 12-19 seconds. This will likely change once the network transitions to Proof of Stake, which aims to enable faster block times, among other improvements.
Getting Started with Ethereum
How to Acquire ETH
There are several ways to obtain ether:
- Cryptocurrency exchanges: Purchase ETH using fiat currency or other cryptocurrencies on platforms like Binance, Coinbase, or Kraken
- Peer-to-peer markets: Buy directly from other users through P2P platforms
- Earning: Receive ETH as payment for goods or services
- Mining: Although this requires significant technical knowledge and hardware investment
Storing Your ETH
Once you acquire ETH, you need to store it securely. Options include:
- Exchange wallets: Convenient for trading but less secure since you don't control private keys
- Software wallets: Applications on your computer or mobile device that give you control of your funds
- Hardware wallets: Physical devices that store your cryptocurrencies offline for maximum security
- Paper wallets: Physical documents containing your public and private keys (though less recommended due to potential risks)
Since no banks are involved, you're responsible for your own funds. If you use your own wallet, carefully safeguard your seed phrase—you'll need it to recover your funds if you lose access to your wallet.
Ethereum Use Cases
Unlike Bitcoin, Ethereum wasn't conceived exclusively as a cryptocurrency network. It's also a platform for creating decentralized applications, and as a tradable token, ether fuels this ecosystem. Therefore, ether's primary use case is probably the utility it provides within the Ethereum network.
That said, ether can also be used similarly to traditional currency—you can buy goods and pay for services with ETH, just like with any other currency.
People can use Ethereum's native currency, ETH, as digital money or collateral. Many also view it as a store of value, similar to Bitcoin. However, unlike Bitcoin, Ethereum's blockchain is more programmable, enabling many more applications for ETH. It can power decentralized financial applications, decentralized markets, exchanges, games, and much more.
Ethereum's Future: ETH 2.0 and Scaling Solutions
Ethereum currently faces significant limitations, primarily around scalability. If Ethereum aims to become the backbone of a new financial system, it must process many more transactions per second. Given the network's distributed nature, this is an immensely difficult problem that Ethereum developers have been working on for years.
To maintain sufficient decentralization, limits must be imposed. The higher the requirements for running a node, the fewer participants there will be, and the more centralized the network becomes. Increasing the number of transactions Ethereum can process could threaten the system's integrity by increasing the load on nodes.
Another criticism of Ethereum (and other Proof of Work cryptocurrencies) is its substantial resource requirements. Mining consumes significant electricity to perform the calculations needed to create new blocks.
Ethereum 2.0
To address these limitations, a major set of upgrades known as Ethereum 2.0 (or ETH 2.0) has been proposed. Once fully implemented, ETH 2.0 should significantly improve network performance.
Key components of ETH 2.0 include:
- Proof of Stake: Replacing energy-intensive mining with staking, where validators are chosen to create new blocks based on the amount of ETH they hold and are willing to "stake" as collateral
- Sharding: Splitting the network into smaller partitions called "shards" that can process transactions and contracts in parallel
- The Beacon Chain: A new blockchain that coordinates the network and manages the proof-of-stake protocol
Sharding Explained
Currently, every node stores a copy of the entire blockchain. Whenever the chain extends, each node must update, consuming bandwidth and available memory.
Using sharding, this may not be necessary. The process involves dividing the network into subsets of nodes—these are our "shards." Each shard processes its own transactions and contracts but can communicate with the broader network of shards as needed. Since each shard validates independently, nodes no longer need to store data from other shards.
Sharding is one of the most complex scaling approaches, requiring significant work to design and implement. However, if successfully deployed, it would be among the most effective, increasing the network's throughput capacity by orders of magnitude.
Plasma and Rollups
Ethereum Plasma is an off-chain scaling solution that aims to increase transaction throughput by moving transactions off the main blockchain. It has similarities with sidechains and payment channels.
With Plasma, secondary chains are anchored to Ethereum's main blockchain but maintain minimal communication. They operate more or less independently, though users still rely on the main chain to resolve disputes or "finalize" their activities on the secondary chains.
Rollups are similar to Plasma in that they aim to scale Ethereum by moving transactions off the main blockchain. A single contract on the main chain holds all funds on the secondary chain and maintains cryptographic proof of this chain's current state. Operators of this secondary chain, who place a bond in the mainnet contract, ensure that only valid state transitions are committed to the mainnet contract.
There are two types of rollups: Optimistic Rollups and ZK-Rollups. Both ensure the correctness of state transitions through different methods.
ZK-Rollups use a cryptographic verification method called zero-knowledge proofs (specifically zk-SNARKs) to validate transactions. This allows different parties to prove to each other that they possess certain information without revealing what that information is. For ZK-Rollups, this information is state transitions sent to the main chain. A significant advantage is that this process can occur almost instantly with practically no chance of corrupt state submissions.
Optimistic Rollups sacrifice some scalability for greater flexibility. Using a virtual machine called the Optimistic Virtual Machine (OVM), they allow smart contracts to run on these secondary chains. However, there are no cryptographic proofs that the state transition sent to the main chain is correct. To mitigate this, there's a slight delay to allow users to challenge and reject invalid blocks submitted to the main chain.
Proof of Stake Implementation
Proof of Stake (PoS) is an alternative to Proof of Work for validating blocks. In a PoS system, blocks aren't mined but rather "forged" or "minted." Instead of miners competing with hash power, a node (or validator) is randomly selected periodically to validate a candidate block. If done correctly, they receive all transaction fees from that block and possibly a block reward according to the protocol.
Since no mining is involved, Proof of Stake is considered less environmentally harmful. Validators don't consume nearly as much energy as miners and can mint blocks on consumer-grade hardware.
Ethereum is scheduled to transition from PoW to PoS as part of Ethereum 2.0 through an upgrade called Casper. Although no exact date has been formalized, the transition represents a fundamental shift in how the network achieves consensus.
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In Proof of Work protocols, miners guarantee network security. Miners won't cheat because it would waste electricity and cause them to lose potential rewards. In Proof of Stake, different cryptoeconomic measures ensure network security.
Instead of the risk of wasted resources, what prevents dishonest behavior is the risk of losing funds. Validators must submit a stake (a token holding) to be eligible for validation. This is a set amount of ether that is lost if the node attempts to cheat or slowly depleted if the node doesn't respond or goes offline.
Frequently Asked Questions
What is Ethereum's scalability problem?
Ethereum can currently process only about 10-15 transactions per second, which is insufficient for global adoption. During periods of high demand, transaction fees become expensive, and processing times increase significantly.
How will Ethereum 2.0 solve scalability issues?
ETH 2.0 addresses scalability through three main components: Proof of Stake consensus, sharding (splitting the network into parallel chains), and improved efficiency in how transactions are processed and stored.
What is staking in Ethereum?
Staking involves locking up ETH to participate in validating transactions and creating new blocks in the Proof of Stake system. Validators are rewarded for their participation, similar to how miners are rewarded in the current system.
When will Ethereum 2.0 be fully implemented?
The transition to Ethereum 2.0 is happening in phases, with the Beacon Chain already launched in December 2020. The merge of the mainnet with the Beacon Chain is expected in 2022, with full sharding implementation to follow.
Will my existing ETH work on Ethereum 2.0?
Yes, existing ETH will be compatible with Ethereum 2.0. The transition is designed to be seamless for users and holders of ETH.
What happens to miners after Ethereum switches to Proof of Stake?
Once Ethereum fully transitions to Proof of Stake, mining will no longer be necessary. Miners may redirect their resources to other Proof of Work cryptocurrencies or transition to validation roles in the new system.
Decentralized Finance (DeFi) on Ethereum
Decentralized Finance (DeFi) is a movement that aims to decentralize financial applications. DeFi builds on public, open-source blockchains that anyone with an Internet connection can access permissionlessly. This is a crucial element for potentially incorporating billions of people into this new global financial system.
In the growing DeFi ecosystem, users interact with smart contracts and each other through peer-to-peer networks and decentralized applications. The significant advantage of DeFi is that while enabling all this, users retain ownership of their funds at all times.
In short, the DeFi movement aims to create a new financial system free from the limitations of the current one. Due to its relatively high degree of decentralization and large developer base, most DeFi applications are currently being built on Ethereum.
DeFi Applications and Use Cases
One of the most popular use cases for decentralized finance is stablecoins. These are tokens on a blockchain with their value pegged to a real-world asset, like a fiat currency. For example, BUSD is pegged to the value of the USD. These tokens are convenient because they exist on a blockchain, making them easy to store and transfer.
Another popular application type is lending. Numerous peer-to-peer services allow you to lend your funds to others and earn interest payments in return. One of the easiest ways to do this is through platforms like Binance Lending—you simply transfer funds to your lending wallet and can start earning interest the next day!
Arguably the most exciting part of DeFi are applications that are difficult to classify. These can include all kinds of decentralized peer-to-peer markets where users can trade unique crypto collectibles and other digital items. They can also enable the creation of synthetic assets, where anyone can create a market for almost anything of value. Other uses might include prediction markets, derivatives, and many more.
Decentralized Exchanges (DEXs)
A Decentralized Exchange (DEX) allows exchanges to occur directly between users' wallets. When you trade on a centralized exchange like Binance, you send your funds to Binance and trade through their internal systems.
Decentralized exchanges are different. Through the magic of smart contracts, they allow you to trade directly from your crypto wallet, eliminating exchange hack risks and other vulnerabilities.
Great examples of decentralized exchanges include Binance DEX, Uniswap, Kyber Network, and IDEX. Many even allow trading from a hardware wallet for maximum security.
The key difference between centralized and decentralized exchanges is intermediary involvement. On centralized exchanges, the platform sits between users' transactions. On decentralized exchanges, tokens are swapped directly between users through smart contracts, eliminating the need to trust an intermediary since contract terms are automatically enforceable.
As of early 2020, DEXs tend to be the most used applications on the Ethereum blockchain. However, trading volume compared to centralized exchanges remains small. If DEX developers improve the user experience to be more welcoming, DEXs could rival centralized exchanges in the future.
Participating in the Ethereum Network
Node Types and Operations
An "Ethereum node" describes any program that interacts with the Ethereum network. An Ethereum node can be anything from a simple mobile wallet application to a computer storing a complete copy of the blockchain.
All nodes function as communication points, but there are different node types on the Ethereum network:
- Full nodes: Download all blocks and verify included transactions are correct. They run all called smart contracts to ensure they receive the same information as other peers. Full nodes are vital for Ethereum's operation—without multiple nodes distributed worldwide, the network would lose its decentralized, censorship-resistant properties.
- Light nodes: Use fewer resources and occupy minimal space, able to run on lower-spec devices like phones or laptops. However, light nodes aren't completely self-sufficient—they don't sync the entire blockchain and require full nodes to provide relevant information.
- Mining nodes: Can be full or light clients but require additional hardware for mining operations.
Running an Ethereum Node
One of the great aspects of blockchains is open access. Anyone can run an Ethereum node and strengthen the network by validating transactions and blocks.
Similar to Bitcoin, several companies offer plug-and-play Ethereum nodes. This might be the best option if you simply want to get a node running quickly, though you'll pay more for convenience.
Ethereum has several different node software implementations like Geth or Parity. If you want to run your own node, familiarize yourself with the setup process for your chosen implementation.
Unless running a special "archive node," a consumer-grade laptop should suffice for running a full Ethereum node. However, it's better not to use your everyday machine, as it could significantly slow it down.
Running your own node works best on devices that can always stay online. If your node goes offline, it can take considerable time to sync with the network once back online. The best solutions are devices that are cheap to build and easy to maintain. For example, you can run a light node even on a Raspberry Pi.
Mining Considerations
Since the network will soon transition to Proof of Stake, mining Ethereum isn't the safest long-term bet. After the transition, Ethereum miners will likely point their mining equipment to another network or sell it entirely.
If you want to participate in Ethereum mining, you'll need specialized hardware like GPUs or ASICs. For reasonable returns, you'll likely need a custom mining rig and access to cheap electricity. You'll also need to set up an Ethereum wallet and configure mining software to use it. All this requires significant time and money investment, so carefully consider if you're prepared for the challenge.
Development and Programming
Like Bitcoin, Ethereum is open-source. Anyone can freely participate in developing the protocol itself or create applications on it. Ethereum currently has the largest developer community in the blockchain space.
Solidity has become the primary programming language for developing smart contracts on Ethereum. Syntactically, it resembles Java, JavaScript, and C++. Essentially, Solidity enables developers to write code that can be broken down into instructions the Ethereum Virtual Machine (EVM) can understand.
It's worth noting that Solidity isn't the only language available to Ethereum developers. Another popular option is Vyper, which more closely resembles Python in its syntax.
Conclusion
Ethereum represents a significant evolution in blockchain technology, expanding beyond digital currency to enable programmable contracts and decentralized applications. While facing challenges around scalability and energy consumption, its ongoing development through Ethereum 2.0 promises to address these issues while maintaining the network's decentralized nature.
As the foundation for much of the decentralized finance (DeFi) ecosystem and countless other applications, Ethereum continues to demonstrate the potential of blockchain technology beyond simple value transfer. Its flexibility and robust developer community position it as a leading platform for innovation in the blockchain space.
Whether you're interested as an investor, developer, or simply curious about blockchain technology, understanding Ethereum provides valuable insight into the future of decentralized systems and their potential to transform various aspects of our digital lives.