A

AMM (Automated Market Maker)

The dominant on-chain DEX mechanism. Uses pooled liquidity + a formula (e.g., Uniswap's x × y = k) instead of an order book — trades execute against the pool, not against a counterparty. Larger trades produce larger slippage.

approve

ERC-20 permission setting a spender’s allowance for one token. It does not itself transfer assets. Check the amount, spender and actual contract call.

Address poisoning

Misleading transaction records or lookalike address prefixes and suffixes lure users into copying the wrong recipient. No fixed dust amount is required. Verify the full address against a trusted source.

B

BIP-39 / BIP-32 / BIP-44

BIP-39 encodes entropy and checksum as a mnemonic and derives a seed with an optional passphrase. BIP-32 describes a key tree; BIP-44 specifies a path convention. Recovery depends on implementation, paths, accounts and supported networks; separately imported keys are not covered.

BIP-39 passphrase / 13th word

An optional string combined with the mnemonic to derive a seed; it need not be one word. Different strings yield different seeds. It is another secret to preserve accurately, and a weak choice may be guessed.

Blockaid

A transaction and signature risk-detection service. Check the wallet’s current integration, supported networks and settings. No warning is not proof of safety.

C

CCTP (Cross-Chain Transfer Protocol)

Circle’s protocol for moving native USDC through source-chain burning and destination minting. Check supported routes, fees, message verification and settlement conditions.

Clear Signing

Hardware wallet feature that displays the actual transaction content on the device screen (contract, function, parameters). Opposite is "Blind Signing" (only a hash shown). Always pick hardware with Clear Signing support.

D

DApp (Decentralized Application)

Application whose logic runs on smart contracts on a blockchain. Examples: Uniswap, Aave, OpenSea. You interact via a wallet, signing approves and transactions.

DEX (Decentralized Exchange)

An exchange without a custodian. Most DEXes are AMM-based (Uniswap, SushiSwap, Curve); some are order-book (dYdX, Vertex).

E

ERC-20 / ERC-721 / ERC-1155

ERC-20 covers fungible tokens such as USDC and WETH; native ETH is not ERC-20. ERC-721 covers NFTs, while ERC-1155 manages multiple token IDs in one contract. Approval calls and scopes differ.

EVM (Ethereum Virtual Machine)

A virtual machine for smart contracts. EVM compatibility helps reuse code and tools but does not guarantee identical upgrades, precompiles, fees or account behavior.

EIP-2612 / Permit

A standard for setting ERC-20 allowances using a valid signature. Nonce, deadline and contract domain constrain it. An unused signature may not appear in allowance lists or be invalidated by clearing the current allowance.

EIP-712

Structured-signature standard. Lets signatures carry fields (spender, value, deadline) rather than raw bytes. Permit phishing depends on it; wallet readability for EIP-712 remains poor.

ENS (Ethereum Name Service)

A system mapping names to addresses and other records. Check spelling, network and resolved address; names can expire, transfer ownership or imitate others.

G

Gas / Gas Price / Gas Limit

The three core concepts of execution fees. Gas = computational units; Gas Price = price per unit you pay; Gas Limit = max gas a single transaction can consume. Total fee = Gas Used × Gas Price.

Gas Token

The network fee asset for ordinary self-funded transactions: ETH on Ethereum, Arbitrum, Base and Optimism; BNB on BNB Chain; POL on Polygon PoS; OKB on X Layer; SOL on Solana. Sponsorship may arrange payment differently.

K

KYC (Know Your Customer)

Identity verification required by AML laws at centralized exchanges. Self-custody wallets don't require KYC.

L

L2 / Layer 2

Systems that expand execution above a base chain, with security and settlement depending on implementation. Arbitrum, Optimism and Base are examples. Polygon PoS should not be conflated with Polygon rollup products.

LayerZero

Cross-chain messaging protocol. In V2, applications configure DVN verification security stacks, with execution separate from verification. Inspect the actual application configuration rather than applying the old oracle-plus-relayer description.

Lock-Mint

Assets are locked on a source chain and a representation minted on the destination. Risk depends on custody, verification and redemption, not the mechanism name alone.

M

MEV (Maximal Extractable Value)

Value obtainable through ordering, including or excluding transactions. Searchers, builders and validators can participate. Sandwiching is one strategy; protected channels have coverage and trust limitations.

Mempool

A node’s pending-transaction pool. Nodes may see different sets; private submission and other network designs need not expose transactions in a public mempool.

Multisig

An account or contract requiring a signature threshold for execution. Inspect the threshold, signer independence, modules and recovery powers; multiple nominal signers need not mean independent control.

N

Nonce

Ethereum account ordering counter. Included failed transactions consume it, and authorization processing can increment it too. A pending transaction may be replaced at the same nonce, without a guarantee of winning confirmation.

P

Permit / Permit2

Permit2 provides standing allowances and single-use signature transfers. Underlying ERC-20 approval, Permit2 permissions and signature nonces are separate controls, not one universal revoke operation.

Private key

Secret signing material. Exposure endangers the accounts it controls, while transfers still follow actual account and token rules. Do not share it with webpages, support agents or synchronized notes.

R

revoke.cash

A permission viewer and manager for supported networks and permission types. Public address lookup can be read-only; revocation needs a wallet signature and network fee. An empty list does not rule out signature or key risks.

Rollup / Optimistic / ZK

Optimistic and validity-proof rollups use different verification approaches. Withdrawal time depends on proof, challenge, submission and settlement procedures, not a universal seven-day or hours-long rule.

S

Seed phrase (mnemonic)

A BIP-39 mnemonic combines with an optional passphrase to derive a seed; it is not a direct textual encoding of one private key. Twelve and twenty-four words are common but not the only valid lengths. Paths and implementations must match, and separately imported keys need separate backups.

SetApprovalForAll

ERC-721/ERC-1155 operator approval for tokens under the relevant contract, not every collection or native coin. Setting it to false revokes that permission once execution succeeds.

Slippage

The drift between quoted and executed price on a swap. Set a "slippage tolerance" = max acceptable drift; trades failing the bound are rejected. See swap / slippage.

Sandwich attack

Transactions arranged around a user’s swap to exploit price changes. Check price impact, acceptable minimum output and channel limitations. Fixed slippage percentages or splitting orders do not guarantee protection.

T

tx hash

A transaction identifier. Ethereum commonly displays 0x plus 64 hex characters; other chains use other encodings. Query the full hash on the correct network, not an abbreviated display.

TVL (Total Value Locked)

Measure of capital locked in a DeFi protocol or chain ecosystem. DefiLlama is the de facto aggregator.

U

USDC / USDT

Dollar stablecoins issued by Circle and Tether respectively. A dollar peg does not make them risk-free cash or bank deposits. Check issuer, freeze, redemption and depeg risks, plus network and contract version.

USDC.e / mirrored USDC

Lock-mint legacy USDC variants on certain L2s (suffix .e or .b). Not Circle's native USDC; some dApps don't accept it. See bridge guide.

W

WalletConnect

Standard protocol connecting wallets to dApps. The QR-code scan flow you use to connect a mobile wallet to a desktop dApp.

X

X Layer

A network using OKB for native fees. Check current official architecture, assets, withdrawal routes and costs rather than old architecture descriptions or fixed arrival times.

Z

ZK / Zero-Knowledge proof

Cryptography proving "I know X" without revealing X. ZK Rollups use ZK to compress L2 state changes into a succinct proof posted on L1.

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