Glossary

Terms used throughout this guide and the API reference.

Keys

Term	Definition
nsk	Spending key. A field element from which every other key is derived. Holding nsk is required to spend. See Connecting a wallet.
ivk	Incoming viewing key. Derived from nsk; decrypts notes sent to any address of the account.
nk	Nullifier key. Derived from nsk; computes nullifiers. Included in a full viewing key.
d	Diversifier. 16 bytes that select one address of an account.
Diversifier index	Integer in [0, 2^32) naming one address of an account; addressAt(index). Index 0 is wallet.address.
pk	Public key of one address. Binds a note commitment to its owner.
pk_d	Diversified public key of one address. The ECDH target that notes are encrypted to.
ck_d	Clue key of one address. Lets a sender attach an FMD clue to a note.
dk	Detection key secret. Tests FMD clues for every address of the account; can be delegated to a server.
Outgoing key	Derived from nsk; seeds the randomness of every output the account sends. With a payee's address, opens what the account sent to that payee. See Output randomness.
Incoming viewing key (IVK)	Encoded ivk (lelantosivk1…). Reads incoming notes; cannot tell which are spent. See Watch-only wallets.
Full viewing key (FVK)	An incoming viewing key plus nk (lelantosfvk1…). Reads incoming notes and their spent status.
Shielded address	Bech32m string with prefix lelantos encoding d, pk_d, pk, and ck_d. An account has one per diversifier index. See Addresses.

Pool and transactions

Term	Definition
MASP	Multi-Asset Shielded Pool. The contract holding shielded funds for every registered asset.
Note	A shielded value: one asset, one amount, one owner. Balances are sums of unspent notes.
Commitment (cm)	The public hash of a note, appended to the Merkle tree.
Nullifier (nf)	A value derived from a note and nk, published when the note is spent. The pool rejects a repeated nullifier.
Merkle tree	Append-only tree of note commitments. A spend proves its inputs are in the tree.
Tree depth (treeDepth)	Height of the Merkle tree. Must match the deployed contract and circuit.
Deposit (shield)	Moving tokens from a public balance into the pool.
Transfer	Moving value between shielded addresses. Publishes no amount.
Withdraw (unshield)	Moving value from the pool to a public address.
Swap	Atomic unshield, trade, and re-shield. See Swap.
Credit note	The note created by a swap's re-shield leg when the trade fills; quote.credit is its value.
Refund note	The note a swap re-shields in the input asset when the trade fails or passes its deadline. A handle registration has one too.
Handle	A short name in the LelantosNameRegistrar that publishes one shielded address, served as an ENS subname of each parent the deployment holds. See Names.
Published address	The account's address at PUBLISHED_DIVERSIFIER_INDEX, the one registerName puts under its handle.
Controller key	The secp256k1 key, derived from nsk, whose signature changes a handle's published value.
Escrow	Holding state of a mined deposit before the relayer adds it to the tree; DepositResult.escrow identifies it.
Flush	The relayer's flushBatch transaction, which adds escrowed deposits to the tree.
publicIn	A deposit's public amount, in circuit units.
publicOut	A withdrawal's public gross amount, in circuit units.
Change	Output notes returning unspent input value to the sender.
Consolidation	A self-transfer that merges several small notes into fewer notes.
Cover	A set of notes whose total is at least the target amount.
Dust	Notes below the selector's dust threshold.

Amounts

Term	Definition
Circuit units	The integer amounts used inside the pool (CircuitAmount): note values, publicIn, publicOut.
Base units	ERC-20 base units (10 ** decimals per token; TokenAmount).
Gross / net	A withdrawal's or swap's amount before (gross, published) or after (net, delivered) the protocol fee.
Money	An amount in both integer spaces, { asset, amount, baseUnits }, as results report it.
scale	Per-asset multiplier from circuit units to token units, set in the registry.
index	Per-asset yield index, scaled by RAY. Equals RAY when the asset earns no yield.
RAY	10n ** 27n, the fixed-point base for index.
rate	The pool's { gross, supply } pair for a yield-bearing asset. Used to size payments.
bps	Basis points; 1 bps = 0.01%.
depositBps, withdrawBps	Per-asset protocol fee rates for each direction. See Fees.
Denomination	A fixed withdrawal amount from an asset's ladder.
Ladder	An asset's ascending list of denominations. See Denominations.

Circuit and proving

Term	Definition
Circuit shape	Number of input and output notes a proof supports. The shipped shape is TRANSACT_4X6.
nIn, nOut	Input and output counts of the circuit shape (4 and 6).
Groth16	The zero-knowledge proof system used for spends.
Witness	The private inputs to a proof, computed before proving.
zkey	The proving key file (~33 MB for 4x6).
Prover artifacts	The circuit .wasm and the .zkey needed to prove.
Output shuffling	Randomizing the order of output notes so the payee and fee outputs cannot be identified by position.

Detection and sync

Term	Definition
Trial decryption	Attempting to decrypt every note with ivk to find the wallet's notes.
FMD	Fuzzy message detection. Clues let a detection key find probable matches with a tunable false-positive rate.
γ (gamma)	FMD precision parameter; controls the false-positive rate.
Sync strategy	full (download all notes, decrypt locally) or matches (server-side detection). See Syncing.
Subscription token	Bearer credential identifying a matches subscription.
Cursor	Position in the note feed from which the next sync resumes.
Spent set	The local copy of every published nullifier.

Services and selection

Term	Definition
Relayer	Service that submits spends on chain, pays gas, and flushes deposits. Paid by a shielded fee note.
fmd-webserver	Read-only indexer serving encrypted notes, tree chunks, and nullifier chunks.
Metaquoter	Service returning swap routes and minOut.
NativeAdapter	Contract that wraps and unwraps ETH for native deposits and withdrawals.
SwapWrapper	Contract that executes a swap's trade between its two legs.
Permit2	Uniswap's token-approval contract, used to authorize deposit transfers.
SFRT	Smallest-First, Random Tiebreak. The default coin-selection algorithm.
Spend cooldown	Minimum age in blocks before a received note can be spent.
Lease	A note selected by a spend in flight, withheld from other spends until it settles.
opId	Correlation id of one operation, on its phases, result, errors, and state().ops.