Crypto Forem: Leyutsega Abebaw

ERC-20, ERC-721,ERC-1155

Leyutsega Abebaw — Thu, 06 Nov 2025 13:15:54 +0000

1.ERC-20 (Fungible Token – Like Coins) Core Functions -total Supply → Returns the total number of tokens in existence. -balanceOf(address account)→ Shows how many tokens a specific address owns. -transfer(address to, uint256 amount)→ Sends tokens from your account to another address. -approve(address spender, uint256 amount)→ Authorizes another address to spend your tokens. -allowance(address owner, address spender) → Checks how many tokens a spender is allowed to use from an owner’s account. -transferFrom(address from, address to, uint256 amount)→ Moves tokens from one address to another using the allowance mechanism. Internal Functions _mint(address account, uint256 amount)→ Creates new tokens and adds them to the specified account. _burn(address account, uint256 amount)→ Destroys tokens from the specified account.
2.ERC-721 (Non-Fungible Token – Unique Items) Core Functions -balanceOf(address owner)→ Returns how many NFTs a specific address owns. -ownerOf(uint256 tokenId)→ Returns the current owner of a specific NFT. -approve(address to, uint256 tokenId)→ Grants permission for another address to transfer a specific NFT. -get Approved(uint256 tokenId)→ Returns the address approved to transfer a specific NFT. -setApprovalForAll(address operator, bool approved)→ Allows or revokes another address’s permission to manage all your NFTs. -is Approved ForAll(address owner, address operator)→ Checks if an operator can manage all NFTs of an owner. -transferFrom(address from, address to, uint256 tokenId)→ Transfers ownership of an NFT from one address to another. -safeTransferFrom(address from, address to, uint256 tokenId)→ Safely transfers an NFT, ensuring the recipient can handle it. Internal Functions _mint(address to, uint256 tokenId)→ Creates a new NFT and assigns it to the specified address. _burn(uint256 tokenId)→ Destroys a specific NFT.
3.ERC-1155 (Multi-Token – Mixed Fungible and Non-Fungible) Core Functions -balanceOf(address account, uint256 id)→ Returns how many tokens of a given ID an address owns. -balance Of Batch(address accounts, uint256 ids)→ Returns multiple token balances in a single call. -set Approval ForAll(address operator, bool approved)→ Grants or revokes permission for an operator to manage all your tokens. -is Approved ForAll(address account, address operator)→ Checks if an operator can manage all tokens of a specific account. -safe Transfer From(address from, address to, uint256 id, uint256 amount, bytes data)→ Safely transfers a specific amount of one token type. -safe Batch Transfer From(address from, address to, uint256 ids, uint256 amounts, bytes data)→ Safely transfers multiple token types in one transaction. Internal Functions _mint(address to, uint256 id, uint256 amount, bytes data) → Creates new tokens of a specific type. _mint Batch(address to, uint256[] ids, uint256 amounts, bytes data)→ Creates multiple token types at once. _burn(address from, uint256 id, uint256 amount)→ Destroys a specified amount of one token type. _burn Batch(address from, uint256[] ids, uint256 amounts) → Destroys multiple token types in a single transaction.

What is a transaction in Ethereum?

Leyutsega Abebaw — Thu, 06 Nov 2025 12:48:25 +0000

*A transaction in Ethereum is like sending a signed message that says: “I, the owner of this wallet, want to send money or trigger a program.”
Every transaction changes something on the blockchain — for example:-Sending ether to another person.
-Running a smart contract (like trading tokens or minting NFTs).
Only Externally Owned Accounts (EOAs)— wallets controlled by people — can start transactions.
The Parts of a Transaction
Each transaction includes several important pieces of data: Part, Meaning, Nonce
A unique number that keeps your transactions in order.
*Gas price
How much you’re willing to pay per unit of work (like “fuel price”).
****Gas limit
The maximum amount of work you’ll allow for this transaction.

*Recipient
The address you’re sending ether or data to.
*Value
The amount of ether you want to send.
****Data
Optional— used if you’re calling a smart contract.
v, r, s
Signature pieces that prove it’s really you who sent it.
All of this information is encoded and sent through the Ethereum network.
Nonce (Transaction Number)
Think of the nonce as the transaction number for your account.
-Your first transaction = nonce 0
-Your second transaction = nonce 1

and so on... It prevents hackers from re-sending old transactions(called replay attacks) and helps the network process them in the right order. *Example (incode):web3.eth.getTransactionCount("0xYourAddress"); This shows how many transactions you’ve already made — that’s your next nonce. *Gas (Transaction Fuel) Ethereum uses gas to pay for computation. It’s like fuel for running a program. -Gas price→how much you’re willing to pay for each “unit of work.” -Gas limit→ the maximum units you’ll allow the transaction to use. If gas didn’t exist, someone could overload the network for free. Gas prevents that. ****Recipient Every transaction goes to a recipient address: -If it’s a normal wallet →the money just moves there. -If it’s a contract address →it runs code (like executing a smart contract function). Digital Signatures (Security) Each transaction must be signed with your private key using something called ECDSA. That signature proves:
You authorized it (ownership).
You can’t later deny it (non-repudiation).
It wasn’t changed after signing (integrity). How a Transaction Is Signed Here’s the simplified process:
Make the transaction data.
Encode it properly (RLP encoding).
Hash it (with Keccak-256).
Sign it with your private key → creates 'v,r,s.
Add the signature to the transaction. This signed message is what actually gets sent to the network. How Transactions Spread Once signed, the transaction is sent to one Ethereum node. That node checks it and shares it with others (like spreading news through friends). This is called flood routing— it helps the transaction reach the entire network quickly.

Understanding Ethereum

Leyutsega Abebaw — Tue, 14 Oct 2025 17:58:02 +0000

Introduction
Ethereum is one of the most widely used blockchain platforms in the world. While Bitcoin focuses mainly on
being a digital currency, Ethereum takes the concept further by offering a platform for smart contracts and
decentralized applications (dApps).
This makes Ethereum more than just a cryptocurrency; it is a global,
decentralized computing platform that enables anyone to build and interact with applications without relying
on a central authority.
In this article, we will explore Ethereum in detail, covering its history, core
components, consensus mechanisms, network structure, cryptography, and real-world applications.
The goal
is to provide beginners with a clear and complete understanding of how Ethereum works and why it matters.
History of Ethereum
Ethereum was proposed in late 2013 by Vitalik Buterin, a young programmer who envisioned a blockchain
capable of more than simple transactions.
Vitalik noticed that while Bitcoin was revolutionary for digital
money, it was limited in programmability. He proposed Ethereum as a platform for smart contracts, which
would allow anyone to create decentralized programs that run autonomously on a blockchain.
The Ethereum
project gained momentum through a crowdfunding campaign in 2014, raising over $18 million.
The network
officially launched on July 30, 2015, with its first release called Frontier. Since then, Ethereum has undergone
multiple upgrades, including Homestead, Metropolis (Byzantium and Constantinople), Istanbul, and most
recently, The Merge, which transitioned Ethereum from Proof of Work to Proof of Stake. Ethereum’s rapid
adoption is due to its versatility: developers can build decentralized applications ranging from finance to
gaming to digital art.
Its ecosystem continues to grow, making it one of the most innovative platforms in the
blockchain space.
Understanding Blockchain Basics
Before diving deeper into Ethereum, it is important to understand the concept of blockchain. A blockchain is
a distributed ledger that records transactions in a way that is secure, transparent, and immutable.
How a Blockchain Works
Transactions are grouped into blocks. Each block is linked to the previous block through a cryptographic hash,
forming a chain.
Once a block is added to the chain, its data cannot be altered, ensuring integrity.Think of
blockchain like a digital notebook that is copied and shared across thousands of computers worldwide. Each
time someone writes a new page (block) in the notebook, every copy of the notebook is updated. This
ensures that everyone sees the same data, and no single person can cheat.
Why Blockchain Matters
Decentralization: There is no central authority controlling the network.
Transparency: Anyone can verify the transactions.
Security: Cryptography ensures data integrity and prevents tampering.Ethereum takes this blockchain concept a step further by adding programmability through the Ethereum
Virtual Machine (EVM), which allows the network to run complex programs in addition to simple
transactions.
Ethereum Virtual Machine (EVM)
The Ethereum Virtual Machine (EVM) is the heart of Ethereum’s programmability. It is a virtual computer that
exists on the Ethereum network and runs smart contracts. Smart contracts are self-executing programs that
automatically carry out rules or agreements when certain conditions are met.
For example, imagine a simple smart contract for a crowdfunding campaign:If the campaign reaches its
funding goal, the money is automatically sent to the creator.
If the campaign fails, funds are automatically
returned to contributors.
The EVM ensures that all nodes in the network execute smart contracts in the same
way, guaranteeing consistency and security. Every transaction that interacts with a smart contract is
processed by the EVM, which updates the global state of Ethereum.
Ether (ETH) and Gas
Ethereum has its own digital currency called Ether (ETH).
ETH serves multiple purposes within the network:

Transaction fees – Known as gas, ETH is used to pay for computations and operations on the Ethereum network.
Incentives – Validators and miners earn ETH for maintaining the network.

What Is Gas?
Gas is a measurement of the computational work required to execute operations, such as sending ETH or
running a smart contract. Every operation on Ethereum consumes a certain amount of gas. The gas fee is
calculated as: Gas Fee = Gas Used × Gas Price. For example, if a transaction uses 21,000 units of gas and the
gas price is 50 gwei (a small fraction of ETH), the total fee is 21,000 × 50 gwei.

Gas fees serve two main purposes:
Prevent spam: Without fees, people could overload the network with unlimited transactions.
Reward validators: Those who process transactions earn ETH, incentivizing them to secure the network.

Accounts and Transactions
Ethereum has two main types of accounts:

Externally Owned Accounts (EOAs) – Controlled by private keys. These are your typical user wallets for sending and receiving ETH.
Contract Accounts – Controlled by smart contract code. These accounts execute actions automatically based on the rules written in the contract.

How a Transaction Works
When you send ETH or interact with a smart contract, a transaction occurs:

Your wallet signs the transaction using your private key.
The transaction is broadcast to the Ethereum network.
Nodes validate the transaction and ensure you have enough ETH.
Once validated, the transaction is added to a new block and recorded on the blockchain. This process ensures security, transparency, and immutability, as all nodes must agree on the transaction before it becomes part of the blockchain.

Smart Contracts
Smart contracts are self-executing programs stored on the Ethereum blockchain. They automatically enforce
the rules encoded in them.
Example: Imagine a decentralized crowdfunding project: Alice wants to raise 10 ETH for a community project.
Contributors send ETH to a smart contract address. If the total reaches 10 ETH, the contract automatically
releases the funds to Alice. If it doesn’t reach 10 ETH, the contract refunds contributors. Smart contracts
eliminate the need for intermediaries, ensuring that agreements are executed automatically, transparently,
and reliably.

Consensus Mechanisms
Ethereum needs a method to agree on the state of the blockchain because there is no central authority.
This is called a consensus mechanism.

Proof of Work (PoW) – The Original Ethereum
Originally, Ethereum used Proof of Work, the same system as Bitcoin. In PoW: Miners solve complex
mathematical puzzles. The first miner to solve the puzzle adds the block to the blockchain. Miners are
rewarded with ETH for their effort. While secure, PoW requires massive computing power and consumes a lot of electricity.

Proof of Stake (PoS) – Ethereum’s Upgrade
In 2022, Ethereum transitioned to Proof of Stake through an upgrade known as The Merge.
In PoS: Validators
lock up (“stake”) ETH to participate in block creation. Validators are randomly chosen to propose or verify
blocks.
Honest behavior is rewarded with ETH; dishonest behavior results in loss of staked ETH. PoS is more
energy-efficient, faster, and scalable than PoW, allowing Ethereum to handle more transactions while
reducing its environmental impact.

Nodes and Clients
The Ethereum network is maintained by nodes, which are individual computers connected to the blockchain.
Each node plays a vital role in verifying transactions, storing blockchain data, and executing smart contracts.

Types of Nodes

Full Nodes – Store the entire blockchain history and independently verify every transaction and smart contract execution. Full nodes are crucial for network security because they prevent fraudulent or invalid data from being added.
Light Nodes – Store only a portion of the blockchain, typically just the block headers. They rely on full nodes for detailed information but are faster and require less storage.

Ethereum Clients
Nodes run software programs called clients to communicate with the network and follow the Ethereum
protocol. Popular clients include:
Geth (Go Ethereum) – The most widely used client, written in Go. Nethermind – Written in .NET, suitable for
enterprise solutions. Besu – Java-based client, often used for private and consortium networks. Having
multiple clients ensures network robustness. If one client has a bug, the others continue to maintain the
blockchain’s integrity. Nodes communicate constantly, sharing new transactions and blocks while executing
smart contracts through the Ethereum Virtual Machine (EVM).

Keys, Wallets, and Security
Ethereum relies heavily on cryptography to ensure security and ownership. Every Ethereum account is
secured with a pair of keys:

Private Key – A secret string of characters that allows you to access and control your account. Anyone with your private key can spend your ETH.
Public Key and Address – Derived from the private key, the address is shared with others to receive ETH or interact with smart contracts.

Wallets
A wallet stores your private key securely and helps you interact with Ethereum.
Wallets come in two main
types:
Software Wallets – Apps like MetaMask that run on your computer or phone.
Hardware Wallets – Physical devices like Ledger or Trezor, which store keys offline for extra security.

Security Best Practices:
Never share your private key.
Use hardware wallets for large amounts of ETH.
Enable two-factor authentication when possible.
Back up your seed phrase in a secure location.
Security is crucial because Ethereum is decentralized — there is no central authority to recover lost or stolen
keys.

Ethereum Ecosystem and Real-World Applications
Ethereum’s versatility allows developers to create decentralized applications (dApps) that serve a wide range
of purposes. Some key areas include:

Decentralized Finance (DeFi)
DeFi applications allow users to lend, borrow, and trade assets without banks. Popular DeFi platforms like
Uniswap and Aave leverage Ethereum smart contracts to automate lending, trading, and yield farming.

Non-Fungible Tokens (NFTs)
NFTs are unique digital assets representing art, collectibles, or virtual items. Ethereum’s blockchain ensures
ownership is verifiable and secure, allowing artists to sell digital creations directly to buyers without
intermediaries.

Decentralized Autonomous Organizations (DAOs)
DAOs are organizations run by smart contracts instead of central management.
Members vote on decisions
using tokens, and the code enforces rules automatically. DAOs can manage funds, propose projects, or
govern communities transparently.

Gaming and Virtual Worlds
Ethereum powers play-to-earn games and virtual worlds where in-game assets are NFTs. Players truly own
their digital items and can trade or sell them independently of the game developers.

Supply Chain and Identity Verification
Ethereum smart contracts can track products from production to delivery, ensuring authenticity and reducing
fraud. Similarly, digital identities can be secured on Ethereum, giving individuals control over personal data.
These applications show that Ethereum is not just a cryptocurrency but a foundation for decentralized
innovation, impacting finance, art, gaming, governance, and more.

Ethereum Upgrades and Ethereum 2.0
Since its launch in 2015, Ethereum has undergone multiple major upgrades to improve scalability, security,
and sustainability. Each upgrade addresses specific network challenges while adding new functionality.

Key Upgrades

Homestead (2016) – The first major stable release, introducing improvements to security and protocol stability.
Metropolis (Byzantium 2017 and Constantinople 2019) – Introduced faster transaction processing, improved privacy, and new smart contract capabilities.
Istanbul (2019) – Focused on performance, reducing gas costs for certain operations, and improving interoperability with other blockchains.
The Merge (2022) – Transitioned Ethereum from Proof of Work (PoW) to Proof of Stake (PoS). This drastically reduced energy consumption and laid the groundwork for Ethereum 2.0.

Ethereum 2.0 (ETH 2.0)
Ethereum 2.0 is a series of upgrades designed to make Ethereum more scalable, secure, and sustainable.
Key features include:
Proof of Stake (PoS): Validators stake ETH to secure the network instead of mining.
Sharding: Ethereum will split the blockchain into smaller “shards” to process transactions in parallel,
dramatically increasing throughput.
Roll ups and Layer 2 Solutions: Technologies that bundle multiple transactions together off-chain, reducing
congestion and gas fees. Ethereum 2.0 ensures that as adoption grows, the network can handle more users
and transactions without slowing down or becoming too expensive.

Common Beginner Questions
Many beginners have questions when starting with Ethereum. Here are some common ones:

Can I Mine Ethereum? After The Merge, Ethereum mining using Proof of Work is no longer possible. Instead, users can participate in the network by staking ETH to become validators.
How Do I Create a Smart Contract? You can write smart contracts using Solidity, Ethereum’s programming language. Tools like Remix IDE make it easy for beginners to create, test, and deploy smart contracts without deep technical knowledge.
What Is the Difference Between Ethereum and Bitcoin? Bitcoin: Primarily a digital currency and store of value. Ethereum: A decentralized platform for running smart contracts and dApps, with Ether as its native currency.
How Can I Safely Store My ETH? Use hardware wallets for large amounts, software wallets for convenience, and never share your private keys. Always back up your seed phrase in a secure place.

Why Ethereum Matters
Ethereum is not just a technological platform; it is shaping the future of decentralization. It empowers
developers, businesses, and individuals to build applications where trust is automated through code rather
than human intermediaries.
From finance (DeFi) to art (NFTs) to governance (DAOs), Ethereum provides a flexible and secure
infrastructure for innovation. Understanding Ethereum allows beginners to: Explore new financial opportunities.
Interact safely with digital applications. Build or participate in decentralized ecosystems.
The Ethereum network continues to grow, attracting developers, users, and organizations worldwide.
Learning Ethereum today means understanding the foundation of tomorrow’s decentralized digital world.

Conclusion
Ethereum is more than a cryptocurrency; it is a revolutionary platform for decentralized computing. By
combining blockchain technology, smart contracts, consensus mechanisms, and secure cryptography,
Ethereum enables transparent, automated, and trustless applications. Beginners who take the time to
understand Ethereum will gain insights into the future of technology, finance, digital ownership, and
decentralized governance. With ongoing upgrades and a vibrant ecosystem, Ethereum continues to shape the
next generation of the internet — a world where users are in control of their own data, assets, and digital
experiences. Whether you are a developer, investor, or curious learner, understanding Ethereum is a crucial
step toward engaging with the future of decentralized technology.

References
Ethereum.org – Intro to Ethereum
Ethereum.org – Consensus Mechanisms
Ethereum.org – Nodes and Clients
Ethereum Keys & Addresses – Mastering Ethereum (GitHub)

Prepared By Leyutsega Abebaw
Date: October 14, 2025.