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Ethereum Glossary

Quick reference for Ethereum concepts used in tests. For detailed explanations, see Ethereum.org Developer Documentation.

Ether Units

Ethereum uses different denominations for expressing amounts:

Unit Value in Wei Common Use
Wei 1 wei Smallest unit (10^-18 ETH)
Gwei 1,000,000,000 wei Gas prices (10^-9 ETH)
ETH 1,000,000,000,000,000,000 wei Main currency (1 ETH)

Conversion formulas:

  • 1 ETH = 10^18 wei
  • 1 Gwei = 10^9 wei
  • 1 ETH = 10^9 Gwei

📖 More on Ether units

Transaction Parameters

Basic Parameters

To

  • Recipient address (contract or account)
  • For contract interactions, this is the contract address

Value

  • Amount of ETH to send with the transaction (in wei)
  • Can be 0 for contract calls that don't require payment

Data

  • Arbitrary data payload (in bytes)
  • For contract interactions: encoded function call (selector + parameters)
  • For simple transfers: usually empty

Nonce

  • Transaction sequence number for the sending account
  • Prevents replay attacks
  • Must be sequential (0, 1, 2, 3, ...)
  • Each account maintains its own nonce counter

📖 More on transactions

Gas Parameters

What is Gas?

Gas is a unit of measurement that represents the computational effort required to execute operations on the Ethereum network.

Why Gas Exists:

  • Metering computation: Every operation (addition, storage write, etc.) costs a specific amount of gas
  • Preventing abuse: Limits infinite loops and spam by making computation costly
  • Resource allocation: Ensures fair distribution of network resources
  • Incentivizing validators: Compensates validators for executing transactions

Key Concept - Gas vs Ether:

Gas is NOT a currency. Think of it like this:

  • Gas = Units of computational work (like liters/gallons for fuel)
  • Gas Price = Cost per unit of gas (in wei or gwei)
  • Transaction Fee = Gas Used × Gas Price (paid in ETH)

Example:

A simple ETH transfer costs:     21,000 gas
A complex smart contract call:   100,000+ gas

If gas price = 50 gwei:
- Simple transfer fee = 21,000 × 50 gwei = 0.00105 ETH
- Complex call fee = 100,000 × 50 gwei = 0.005 ETH

Common Operations and Their Gas Costs:

Operation Approximate Gas Cost
ETH transfer 21,000
ERC-20 transfer ~65,000
Uniswap swap ~100,000-150,000
NFT mint ~50,000-100,000
Smart contract creation 200,000+

📖 Ethereum Gas Explained

Gas Limit

  • Maximum number of gas units the transaction is allowed to consume
  • Acts as a safety cap to prevent overspending
  • If actual gas used exceeds this limit, transaction reverts (but you still pay for gas used until failure)
  • If transaction uses less than limit, unused gas is refunded
  • Measured in gas units (not wei or gwei)

Example:

You set Gas Limit = 100,000
Actual usage = 65,000 gas
→ Transaction succeeds, 35,000 gas refunded

You set Gas Limit = 50,000
Actual usage would be 65,000 gas
→ Transaction fails at 50,000, you pay for 50,000 gas used

Legacy Gas Model (Type 0 transactions):

Gas Price

  • Price per gas unit in wei
  • Total cost = Gas Used × Gas Price
  • Set by user, higher price = faster inclusion

EIP-1559 Gas Model (Type 2 transactions):

Max Fee Per Gas

  • Maximum total price per gas unit you're willing to pay (in wei or gwei)
  • Includes base fee + priority fee
  • Actual fee may be lower

Max Priority Fee Per Gas

  • Tip to validators/miners (in wei or gwei)
  • Also called "priority fee" or "tip"
  • Incentivizes transaction inclusion

How EIP-1559 works:

Actual fee = Base Fee + Priority Fee
Base Fee = Set by protocol (burned)
Priority Fee = Min(Max Priority Fee, Max Fee - Base Fee)

📖 More on gas and fees
📖 EIP-1559 specification

Network Parameters

Chain ID

  • Unique identifier for each Ethereum network
  • Common chain IDs:
    • 1 - Ethereum Mainnet
    • 5 - Goerli Testnet
    • 11155111 - Sepolia Testnet
    • 137 - Polygon
    • 42161 - Arbitrum One
  • Prevents replay attacks across different networks

📖 Chainlist.org - Complete list of chain IDs

Cryptographic Concepts

BIP32 Derivation Path

  • Hierarchical deterministic wallet path
  • Format: m/purpose'/coin_type'/account'/change/address_index
  • Example: m/44'/60'/0'/0/0
    • 44' - BIP44 purpose (hardened)
    • 60' - Ethereum coin type (hardened)
    • 0' - First account (hardened)
    • 0 - External chain (non-hardened)
    • 0 - First address (non-hardened)
  • The ' mark indicates hardened derivation

📖 BIP32 specification
📖 BIP44 specification

Elliptic Curve Cryptography

secp256k1

  • Elliptic curve used for Ethereum account keys
  • Same curve as Bitcoin
  • Provides 128-bit security level

BLS12-381

  • Elliptic curve used for Ethereum 2.0 validator keys
  • Supports signature aggregation
  • Used in beacon chain consensus

📖 More on Ethereum accounts

Smart Contract Concepts

Function Selector

  • First 4 bytes of the keccak256 hash of the function signature
  • Example: balanceOf(address) → 0x70a08231
  • Used to identify which function to call in contract data

ABI (Application Binary Interface)

  • Standard for encoding/decoding contract function calls
  • Defines function signatures, parameter types, return types
  • Tests use ABI encoding for contract interactions

📖 More on smart contracts
📖 Contract ABI specification

Proxy Contracts

  • Contracts that delegate calls to implementation contracts
  • Allows contract upgrades without changing address
  • Common patterns: Transparent proxy, UUPS proxy
  • Tests verify app can handle proxy interactions

📖 More on proxy patterns

Token Standards

ERC-20

  • Standard for fungible tokens
  • Common functions: transfer(), approve(), balanceOf()
  • Examples: USDC, DAI, USDT

📖 EIP-20 specification

ERC-721

  • Standard for non-fungible tokens (NFTs)
  • Each token has unique identifier
  • Examples: CryptoPunks, Bored Ape Yacht Club

📖 EIP-721 specification

ERC-1155

  • Multi-token standard (fungible + non-fungible)
  • Efficient batch operations
  • Examples: OpenSea Shared Storefront

📖 EIP-1155 specification

Message Signing

EIP-191 (Personal Sign)

  • Standard for signing arbitrary messages
  • Format: \x19Ethereum Signed Message:\n{length}{message}
  • Used by MetaMask and other wallets
  • Prevents message from being valid transaction

📖 EIP-191 specification

EIP-712 (Typed Structured Data)

  • Standard for signing typed structured data
  • Type-safe, human-readable signing
  • Used for permits, orders, votes, etc.
  • Includes domain separator for context

📖 EIP-712 specification

Ethereum 2.0 / Consensus Layer

Validator

  • Entity that participates in Ethereum consensus
  • Requires 32 ETH deposit
  • Uses BLS12-381 keys (different from account keys)

Beacon Chain

  • Ethereum's proof-of-stake consensus layer
  • Coordinates validators
  • Separate from execution layer (where transactions happen)

Deposit Contract

  • Address: 0x00000000219ab540356cBB839Cbe05303d7705Fa
  • Receives validator deposits (32 ETH)
  • Bridge between execution and consensus layers

📖 More on Ethereum staking

Test-Specific Terms

Blind Signing

  • Signing transactions/messages without full parsing
  • Used when app doesn't recognize contract or function
  • Requires user acknowledgment of risk

Transaction Check

  • Off-chain analysis of transaction effects
  • Detects potential threats (scams, phishing)
  • Displays warnings or blocks dangerous transactions

Generic Clear Signing (GCS)

  • Framework for parsing any smart contract interaction
  • Uses external descriptors to format display
  • Allows clear signing without app updates

Gating Descriptor

  • Third-party security information about contracts
  • Displayed to users during signing
  • Provides additional context and warnings

Trusted Names

  • Human-readable names for addresses
  • Examples: ENS names, token tickers
  • Verified through challenge-response protocol

Additional Resources