Skip to main content

Glossary

Short definitions of the terms used across these docs. Each entry links to the page that covers it in full.

A–C​

  • Account: An on-chain AccountId32 that holds a public balance and signs transactions. An EVM signer maps to one, and the runtime maps H160 addresses to accounts. See Accounts.
  • Anonymity set: The notes a spend could have consumed, as an observer sees it: every note in the tree whose root the spend names. See Privacy Architecture.
  • Asset id: The u32 that names a note's asset; 0 is ORB, the only asset the pool moves. It is public in every operation. See Notes.
  • Baby JubJub: The elliptic curve, defined over the BN254 scalar field, on which shielded-pool keys live; they are confined to its prime-order subgroup of order l. See Keys.
  • Blinding: The field element in a commitment that makes its other fields unguessable. It is random, or derived by sender and recipient when the sender names its address. See Notes.
  • Canonical spending key: A spending key in [1, l). The spend circuits refuse any other, so each note has exactly one nullifier. See Transfer Circuit.
  • Change note: The note that returns the rest of a spend to its sender: a transfer's second output, or the change of a partial unshield. See Transaction Lifecycle.
  • Circuit version: The version of a circuit's verification key that a call names. Only registered, non-retired versions verify; transfer 3, unshield 3 and shield 1 are active. See On-Chain Verification.
  • Commitment: Poseidon4(value, asset_id, owner_pk, blinding), the 32-byte leaf the chain stores for a note. See Notes.

D–L​

  • Disclosure key: An orbdisc: string that reveals one note's fields, so a third party can recompute its commitment and check that the chain holds it. It grants no spending power. See Disclosure Key Format.
  • Dummy input: A zero-value input slot that pads a one-note transfer. Its nullifier is zero and its root repeats the real one. See Transfer Circuit.
  • Fee (spend fee): The amount a private transfer or unshield pays out of the spent note, at least 0.001 ORB, credited to the validator that authored the block. See Spend Fees.
  • Incoming viewing key: The key that decrypts memos sent to you. It is part of your privacy address. See Keys.
  • Leaf / leaf index: A commitment's slot in the forest and its global position; the tree is leaf_index >> 20. See Merkle Forest.

M–N​

  • Memo: The 180-byte encrypted envelope stored with each commitment (nonce, ciphertext, MAC, ephemeral key). It carries the note's plaintext to its owner. See Notes and Note Discovery.
  • Merkle forest: The sequence of depth-20 Poseidon Merkle trees that hold every commitment: one active tree, the rest sealed. See Merkle Forest.
  • Merkle root: The hash at the top of a tree. A spend proves membership against a root the chain still knows. See Merkle Forest.
  • Note: A private record of value: value, asset id, owner key and blinding. Only its commitment is on-chain. See Notes.
  • Nullifier: Poseidon2(commitment, spending_key), published when a note is spent. It marks the note spent without revealing which commitment it belongs to. See Notes.

O–P​

  • Outgoing viewing key: The key that lets a sender reopen what it sent, including sent history and payment slips, after a restore. See Note Discovery.
  • Payment slip: A text the sender shares after a private transfer, which the recipient imports to find and check the note. See Payment Slips.
  • Pending fees: Spend fees credited to a validator in PendingFees. The tokens stay in the pool until the validator claims them. See Spend Fees.
  • Poseidon: The SNARK-friendly hash behind commitments, nullifiers and Merkle nodes. See ZK Proofs.
  • Prepared key: A verification key stored in pre-processed form, so verifying a proof skips the per-key preparation work. See ZK Verifier Reference.
  • Privacy address: An orbpriv3: string holding your owner key, incoming viewing key and a checksum. A sender needs it to pay you privately. See Keys.
  • Private transfer: An unsigned spend of one or two notes into two new notes, entirely inside the pool. See Transfer Circuit and Private Transfer.
  • Proof: A 128-byte Groth16 proof over BN254 that a spend or deposit statement holds, without revealing its private inputs. See ZK Proofs.

R–S​

  • Recover Notes: The app action, under More actions, that scans the whole pool to rebuild your notes, their spent state, sent history and payment slips. See Recovering Notes.
  • Sealed tree: A tree that filled its 2^20 leaves and was closed. Its final root is kept permanently and stays valid for spends. See Merkle Forest.
  • Sender identity: What a payment tells its recipient about who paid: anonymous, a self-chosen pseudonym (unverified), or the sender's privacy address (verified). See Note Discovery.
  • Shield: A signed call that deposits public tokens and inserts one commitment, with a proof that the commitment opens to the deposit. See Shield Circuit.
  • Shielded Pool / shielded pool: Capitalised, the app page (/wallet/shielded) that holds the Vault card and the operations. Lower case, the on-chain pallet that stores commitments, nullifiers and deposits. See Private Vault and System Overview.
  • Subtree root: The Merkle node at level 6, the root of 64 leaves. The wallet builds a path from subtree roots and a window of leaves. See Merkle Forest.

T–Z​

  • Unshield: An unsigned spend of one note that pays an amount to a public account, optionally returning change as a new note. See Unshield Circuit.
  • Unsigned extrinsic: A transaction no account signs. Private transfers and unshields are submitted this way and admitted by the pool's own validation. See Spend Validity.
  • Vault (Private Vault): The card in the app's Shielded Pool page that holds your keys and notes. A signature unlocks it; locking wipes the keys from the session. See Private Vault.
  • Verification key: The public key of a circuit version, stored on-chain, against which proofs are checked. See On-Chain Verification.
  • View tag: The first byte of a memo's nonce, derived from the shared secret. It lets a wallet skip almost every memo not meant for it without decrypting. See Note Discovery.