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Glossary

Active Authentication (AA)​

A security feature in biometric passports aimed at preventing unauthorized copying of passport data.

Biometric Passport​

A passport that includes biometric information, such as a facial photograph, typically includes an RFID chip containing data for biometric verification, personal details, an expiration date, and the issuer's digital signature.

Bundling​

Bundling is the process of combining multiple EVM transactions into a single transaction.

Circom Circuit​

A Circom circuit is a computational construct used in zero-knowledge proof systems, defining constraints for efficient verification. It enables the generation and verification of proofs, preserving privacy by allowing one party to convince another of a statement's validity without revealing additional information.

Decentralized application (DApp)​

A DApp is an application of one or more smart contracts running on a blockchain and a user interface.

Decentralized exchange (DEX)​

A service that exchanges one token for another on the same chain, like a currency exchange.

Decentralized identifier (DID)​

A DID is a unique identifier that is registered with a distributed or decentralized network.

Delegated proof of stake​

Delegated proof of stake is a way of using consensus to select validators. Users propose themselves as validators, and other users that trust them stake tokens on their behalf. Users with the most staked tokens become validators for a certain length of time.

DG1 Personal Details​

A data group within a biometric passport includes the passport holder's primary identity information, such as name, date of birth, nationality, and passport number.

DG15: Active Authentication Public Key​

The data group within a biometric passport includes the public key used for Active Authentication (AA).

DG2 Facial Photograph​

Data group within a biometric passport containing the passport holder's portrait.

Digital autonomous organization (DAO)​

A DAO is a member-owned community without centralized leadership or governing bodies. Rarimo uses a DAO to manage its threshold signature scheme.

Distributed key generation (DKG)​

DKG is a method for creating a key by combining secrets from multiple parties. As a result, no individual party can construct the key without secrets from the other parties.

Edwards-curve Digital Signature Algorithm (EdDSA)​

EdDSA is a complex public key cryptography signature algorithm that is based on Edwards curves.

Elliptic Curve Digital Signature Algorithm (ECDSA)​

ECDSA is a complex public key cryptography signature algorithm in which keys are generated via elliptic curve cryptography.

Ethereum Virtual Machine (EVM)​

A computation engine that is the foundation for EVM-compatible blockchains such as Ethereum and Polygon. See ethereum.org.

Iden3 protocol​

The Iden3 protocol is a framework for issuers to create identities and for verifiers to verify claims about those identities using tools such as ZKPs. Rarimo's identity protocol is based on Iden3.

Identity state​

In the Iden3 protocol, the Identity State consists of multiple Sparse Merkle Trees(SMT) that describe the status of claims associated with an identity. The state is stored on-chain and is used during the ZKP verification.

JSON Web Zero-knowledge (JWZ)​

JSON Web Zero-knowledge (JWZ) is an open standard that employs zero-knowledge technology for secure messaging. It facilitates message exchange between parties while concealing the sender's public keys. The JWZ format includes a header defining token features, a payload with the message, and a proof representing a zero-knowledge authentication based on the authentication circuit.

Machine-Readable Zone (MRZ)​

A portion of a passport that contains key personal data in a format readable by machine scanners.

Merkle tree​

A Merkle tree stores hashes of data in a tree that allows you to verify the contents of the tree. You can use Merkle branches to follow the hashes through the tree to verify that a specific piece of data is in the tree.

MetaMask Snap (Snap)​

A Snap is an application built by third-party developers that adds features and functionality to MetaMask. Snaps can connect to blockchain protocols, show insights about transactions, display notifications, add new features, and more. Rarimo has its own Snap - Rarime, which is used to store identity credentials, manage them, create ZKPs and submit these proofs to DApps.

NFC (Near Field Communication)​

A technology used for short-range communication between devices, often used in passports for wireless data transfer.

Non-fungible token (NFT)​

An NFT is a piece of data stored on a blockchain that certifies a digital asset to be unique and not interchangeable with any other asset. NFTs are different from fungible tokens such as BTC and ETH because fungible tokens are equivalent and interchangeable.

Oracle​

In general blockchain terms, Oracles provide information from outside a blockchain to smart contracts on the blockchain. Rarimo oracles observe blockchains for events, deliver these events to the Rarimo core, and verify events from other oracles. See Oracles.

Passport-Derived Profile​

A digital identity credential for Web3 derived from a biometric passport, allowing selective disclosure of passport data through zero-knowledge proofs.

Proof of Humanity (PoH)​

Proof of Humanity is a secure on-chain verification protocol that allows DApps to filter out bots and ensure that only verified humans are using their services. Currently, Rarimo partners with the four biggest identity providers in the space: Worldcoin, Unstoppable Domains, Gitcoin Passport, and Civic.

After passing the verification, the user will receive his VC (and an SBT), proving he is a real human. Rarimo uses ZKPs to preserve users' privacy and ensure that no information, other than the fact that they are verified humans, is revealed.

Rarimo​

Rarimo is a protocol for messaging data and bridging assets between different blockchain-based systems. Rarimo consists primarily of smart contracts, services, and oracles that automate these tasks.

Relayer​

The Rarimo relayer service helps automate cross-chain operations. When one bridge contract locks tokens, it generates a witness to prove that it has the tokens. The relayer sees that witness and sends a transaction to another bridge contract to unlock tokens on another chain.

RMO​

RMO is the Rarimo token. The RMO token is used for governance of the Rarimo project, among other things. Users can stake RMO tokens to become oracles.

Secp256k1​

Secp256k1 refers to the parameters used in cryptography algorithms such as ECDSA. See Secp256k1.

Slashing​

Slashing is a penalty towards the validator for actions contrary to the consensus protocol.

Penalties may include, but are not limited to:

  • Burning some amount of their stake
  • Jailing

Smart contract​

Smart contracts are programs that run on EVM-compatible blockchains. They can provide public functions and accept transactions, such as selling NFTs or exchanging tokens. Smart contracts provide the logic for NFTs and decentralized applications.

Soulbound Token (SBT)​

Soulbound tokens are tokens that cannot be transferred. They often represent parts of a user's identity, history, or accomplishments.

Sparse Merkle Tree​

A data structure designed for efficiently storing and verifying large data sets with minimal storage requirements.

Swap contract​

Swap contracts are smart contracts that exchange one token for another token on the same chain via a decentralized exchange (DEX).

Tendermint​

Tendermint is an open-source BFT consensus engine for launching blockchains. Rarimo is built on the Tendermint. It consists of:

  • Tendermint Core - BFT consensus engine
  • Cosmos SDK - blockchain application framework
  • IBC protocol - the protocol for inter-blockchain communication

Tendermint allows to write DApps in any language and replicate it on machines participating in the consensus. It also facilitates communication with other blockchains using the IBC (Inter-blockchain communication) Protocol. On a high level, it's an easy solution to create your own blockchain, which can communicate with other blockchains, too.

Threshold Signature Scheme (TSS)​

TSS is a cryptographic method to produce a single signature from a pool of parties, none of which have access to all of the keys to create the signature by themselves. This process uses distributed key generation (DKG) to generate the key. See TSS.

Validator​

Validators are nodes that verify that transactions are valid before adding them to the blockchain.

Verifiable Credential (VC)​

VCs represent claims such as proof of ownership of an account. They include a digital signature of the issuer that allows users to verify that the credential is authentic.

Zero-Knowledge Proof (ZKP)​

A ZKP is a cryptographically secure piece of information that proves that a certain user meets a certain requirement without revealing any specific information about the user. For example, a ZKP can verify that a user is above a certain age without revealing the user's actual age.

Zero-Knowledge Succinct Non-Interactive Argument of Knowledge (zk-SNARK)​

A zk-SNARK is the type of ZKP that Rarimo Identity Protocol uses. One characteristic of zk-SNARKs is that they are non-interactive, meaning that the user and verifier interact only once, unlike some other types of ZKPs.

ZKML (Zero-Knowledge Machine Learning)​

ZKML stands for Zero-Knowledge Machine Learning, which combines zero-knowledge proofs (ZK proofs) with machine learning algorithms. It enables machine learning tasks to be performed on encrypted or private data without revealing the data itself, ensuring privacy and confidentiality.