Connecting a Wallet to Web3.unity: A Step-by-Step Guide

Metamask is the world's most popular crypto wallet with over 21 million users, serving as a bridge between users and the blockchain. Unlike traditional bank apps that store funds at the bank, crypto wallets connect to the blockchain where funds actually reside. Public Keys (Wallet Addresses) function like bank account numbers and can be safely shared to receive funds. Private Keys function like passwords and must never be shared, as they grant full access to funds. Unlike traditional banking where passwords can be reset, crypto Private Keys are irreversible and cannot be changed if compromised. The similarity between Private and Public Keys often causes confusion, so always double-check which key you are copying.

Public and private keys form the foundation of blockchain cryptography for security, privacy, and transaction authenticity. A private key is a unique, randomly generated code (numbers and letters) that only the owner should know, used to sign transactions and prove wallet ownership without revealing the key. Losing a private key means losing access to funds, and sharing it is like giving someone full bank account access. A public key is derived from the private key using cryptographic algorithms (like ECDSA in Ethereum), shared publicly as an address where others can send funds. Although linked, it's practically impossible to deduce the private key from the public key due to mathematical complexity. MetaMask is a browser extension wallet for interacting with blockchains. Installation involves visiting the MetaMask website and adding it as a browser extension. Creating a wallet involves setting a secure password (at least 8 characters with letters, uppercase, numbers, and special characters). The critical recovery phrase (seed phrase) is a 12-word master key that must be written down in exact order and stored securely (like in a safe). This phrase should never be shared with anyone, including MetaMask support, as anyone requesting it is likely attempting a scam.

When using a blockchain wallet, the blockchain assigns two critical keys: a public key (which functions like a bank account number/RIB - this is what others use to send you funds) and a private key (which acts as your password to access and control your funds). The private key must be kept secure at all times because it provides complete access to your cryptocurrency holdings. Unlike traditional banking, there is no customer support to recover lost private keys.

Blockchain wallets contain two essential cryptographic keys: the private key and the public key. The private key must remain strictly confidential and is used to digitally sign transactions, functioning like a password that grants full control over associated funds. The public key, derived from the private key through encryption, serves as the user's identity or wallet address on the blockchain and can be freely shared. When making a transaction, the sender combines transaction data with their private key using a hashing algorithm to create a digital signature. Other nodes verify this signature by applying the sender's public key to confirm the transaction was authorized by the rightful owner. This asymmetric cryptography system ensures secure, verifiable transactions without requiring centralized intermediaries.

Blockchain security methods include public key cryptography. A public key (a long random-looking string of numbers) is an address on the blockchain; value tokens sent across the network are recorded as belonging to that address. A private key acts like a password giving access to digital assets or the ability to interact with corresponding data. A public key is associated with the private key so anyone can make an encrypted transaction to the public key address, but only the corresponding private key can decipher it. This means effective security only requires keeping the private key private while the public key can be openly distributed.

EVM (Ethereum Virtual Machine) networks are blockchains that use the same virtual machine as Ethereum, including Avalanche C-Chain, Arbitrum, Base, Polygon, Linea, and Optimism. These networks have addresses starting with '0x' and can be accessed through a single wallet address. Gas fees range from $1-20 depending on network congestion. Unlike non-EVM blockchains like TON, Cosmos, and Tron, EVM networks share a unified address system where assets sent to an address will arrive in the corresponding network. This structure makes EVM networks more accessible for DeFi applications and cross-chain asset management.

The Ethereum Virtual Machine (EVM) is a distributed processing system that operates differently from traditional computers. Unlike register machines, the EVM uses a stack-based architecture similar to Java. Users 'pop' items on and off the stack for collective processing. Gas in Ethereum is the mechanism for paying for computational resources, representing the cost of running code in the virtual machine. Gas prices are based on the collective costs of running all the servers that maintain the network. Experienced C programmers can write highly optimized code that runs faster and consumes less gas compared to programmers who only use JavaScript.

Gas fees are the transactional costs required to use the Ethereum network. When users send transactions, they must pay miners gas fees as compensation for processing those transactions. In May of the year discussed, gas fees could reach as high as $69 to send someone just one dollar worth of Ethereum, making basic transactions prohibitively expensive.

Blockchains are categorized as EVM (Ethereum Virtual Machine) compatible or non-EVM. EVM-compatible blockchains (Arbitrum, Optimism, Polygon, BNB Chain) use the same programming language and infrastructure as Ethereum, allowing the same wallets and tools. Non-EVM blockchains (Solana, Sui, Near, Aptos) use different programming languages and require different wallets. Each blockchain requires a native token to pay transaction fees (gas): ETH for Ethereum, SOL for Solana, BTC for Bitcoin, BNB for BNB Chain. These fees are typically small (fractions of a cent), but users must hold the native token to perform any transaction. Without the native token, users cannot pay network fees and therefore cannot operate on that blockchain.

Gas in Ethereum is a unit that measures the computational work required to execute smart contracts, with each operation having a specific gas cost (e.g., ADD costs 3 gas, MUL costs 5 gas). Users specify a gas price (bidding system) and gas limit (maximum units to spend), and the total transaction fee is calculated as (base fee + tip) × gas limit. The London upgrade introduced a base fee (minimum price per gas unit, automatically calculated and burned) and a tip (priority fee for miners), while Max fee per gas provides a ceiling for predictable transaction settlement with any excess refunded to users.

ERC20 is an Ethereum Request for Comments standard that defines a set of functions and events enabling token compatibility across wallets, exchanges, and decentralized applications. The standard includes: name (token name), symbol (token symbol), decimals (default 18), totalSupply (maximum supply), balanceOf(address) (returns balance), transfer(to, value), transferFrom(from, to, value), approve(spender, value), and allowance(owner, spender). Events Transfer and Approval broadcast transactions to the network. The index keyword marks event parameters as searchable by block explorers. This standardization ensures tokens work interchangeably across the Ethereum ecosystem.

ERC-20 is the most common token standard used on the Ethereum blockchain. It defines how tokens should behave on the Ethereum network, including how they can be transferred, approved, and interacted with. Many stablecoins like USDT, USDC, and DAI are issued as ERC-20 tokens on the Ethereum network. This standardization allows different tokens to work together on the same blockchain.

The ERC20 token standard is a draft specification created in 2015 that defines what a token contract should look like on the Ethereum blockchain. Virtually all modern custom tokens follow this standard. The key functions include: totalSupply (returns total tokens in circulation), balanceOf (returns balance for a given address), transfer (sends tokens from one address to another), transferFrom (allows permissioned spending on behalf of another address), approve (gives permission to another address to spend tokens), and allowance (returns how much an address is allowed to spend). Additionally, transfer and approval events log these actions for transparency.

ERC stands for Ethereum Request for Comments, similar to BIP (Bitcoin Improvement Proposal), representing a community-driven process for proposing improvements to the Ethereum network. ERC-20 is a specific token standard (ID 20) that establishes rules developers must follow when creating tokens on the Ethereum blockchain. These rules govern token transferability, transaction approval methods, user access controls, and total supply limits. ERC-20 ensures compatibility across the Ethereum ecosystem, allowing over 350,000 different tokens to interoperate seamlessly. Popular examples include Tether (a stablecoin pegged to the US dollar) and BAT (Basic Attention Token used in the Brave browser ecosystem).

The ERC-20 standard is the most widely adopted protocol for creating fungible tokens (cryptocurrencies) on Ethereum-based blockchains, requiring smart contracts to implement specific functions (name, symbol, decimals, totalSupply, balanceOf, transfer, transferFrom, approve, allowance) and events (Transfer, Approval) to ensure compatibility with wallets, exchanges, and DeFi applications.