Commitment: Cryptographic value computed from hidden data (for example, amount and secrets). It lets others later verify that revealed data is consistent, without learning the data from the commitment itself.
Note: Private record that represents ownership of some value plus the secrets needed to prove it. The note is usually stored off-chain or encrypted; on-chain you only see commitments, nullifiers and proofs.
Nullifier: Unique value derived from a note’s secret and revealed when the note is spent. The system stores used nullifiers to prevent double-spending without exposing which note belonged to which party.
Stealth Address: is an address generated per transaction so that multiple payments to the same party cannot be easily linked on-chain. The recipient publishes some public information once; senders use it to derive fresh, unlinkable addresses.
View Key: is a cryptographic key that allows read-only access to encrypted state, like private balances or notes. It enables controlled visibility for auditors, regulators, or internal control functions.
Data Availability (DA): The guarantee that all transaction and state data needed to recompute and verify the system is actually published and retrievable. If DA fails, independent verifiers cannot reliably check state, even if proofs appear valid.
Data Availability Layer (DA Layer): A dedicated network or service that publishes and stores the data required for DA (for example, rollup or application data), separate from the main execution chain.
Sequencer: Layer 2 operator that accepts transactions on a L2 network, orders them, and produces blocks or batches that are later finalized on Layer 1 (like Ethereum).
Prover: Entity that runs a specified computation on given inputs (public and private, like L2 state transistions, private notes,...) and outputs both the result and a cryptographic proof that it was computed correctly. Provers may see plaintext data, so who runs them and how they are operated is an explicit part of the trust and privacy model.
Verifier: Entity (often a smart contract) that checks proofs from provers and decides whether to accept the claimed result (for example, a new state root or settlement outcome).
Relayer: Third party that submits transactions on behalf of users to hide identity
Paymaster: ERC-4337 entity that defines how gas fees for user operations are paid or sponsored. It allows us to implement controlled gasless flows or internal fee routing.
Scaling Rollup: ZK rollup focused on throughput/cost; state public within L2 (ZKsync, Scroll)
Privacy Rollup: ZK rollup designed for encrypted/private state (Aztec)
Validium: Validity proofs on L1; data availability off-chain
Volition: Hybrid model allowing per-transaction choice between on-chain and off-chain DA
DvP (Delivery vs Payment): Atomic settlement ensuring asset delivery only if payment occurs
PvP (Payment vs Payment): Atomic exchange of two payment obligations
TCA (Transaction Cost Analysis): Post-trade analysis of execution quality and slippage
AoR (Audit on Request): Selective disclosure mechanism generating compliance reports on-demand
RFQ (Request for Quote): OTC trading workflow where market makers provide quotes privately
Best Execution: Obligation to obtain most favorable terms when executing client orders
ERC-3643: Ethereum standard for permissioned tokenized securities with built-in compliance framework
ERC-7573: Standard for conditional cross-chain settlement coordination
EIP-6123: Ethereum standard for derivatives contracts with automated lifecycle management
EIP-5564: Stealth address standard for unlinkable payments
ISO 20022: International messaging standard for financial services communication
ICMA BDT: International Capital Market Association Bond Data Taxonomy for standardized bond information
FHE (Fully Homomorphic Encryption): Cryptographic technique allowing computation on encrypted data
Zero-knowledge Proof: A proof that reveals no more information than the validity of the statement it supports.
SNARK/STARK: Zero-knowledge proof systems (Succinct Non-interactive Arguments of Knowledge/Scalable Transparent Arguments of Knowledge)
Co-SNARK: Collaborative zero-knowledge proofs where multiple parties jointly prove properties
Shielded Pool: Privacy mechanism using cryptographic commitments to hide transaction details
Confidential Contract: Smart contract that operates on encrypted state while maintaining verifiability
Circom/Groth16: Popular zero-knowledge proof system and domain-specific language
PLONK: Zero-knowledge proof system with universal trusted setup
TEE (Trusted Execution Environment): Hardware-based secure computation environment
MPC (Multi-Party Computation): Cryptographic technique for joint computation without revealing inputs
ONCHAINID: Decentralized identity system used by ERC-3643 for KYC/eligibility verification
KYC/AML: Know Your Customer/Anti-Money Laundering regulatory compliance requirements
Attestations: Cryptographically signed claims about identities, credentials, or data that can be verified on-chain with minimal disclosure. See Pattern: Attestation Verifiable On-Chain for implementation approaches including EAS, W3C Verifiable Credentials, and ONCHAINID.
EAS (Ethereum Attestation Service): One implementation of on-chain attestation protocol. See attestations pattern for holistic overview.
Crypto-Registry: Regulatory registry for digital asset compliance (eWpG requirement)
Merkle Tree: Cryptographic data structure for efficient membership proofs
eWpG: German Electronic Securities Act regulating tokenized securities
MiCA: EU Markets in Crypto-Assets regulation
GENIUS Act: US legislative framework for digital asset regulation
Oracle: External data provider for blockchain smart contracts
Custodian: Financial institution responsible for safeguarding digital assets