The MOBI Standards Glossary of Terms is a living document that compiles and defines all terms used in MOBI Standards. As MOBI and its members create and update Standards, new terms will be added to the Glossary.

Glossary of Terms Feedback Form – this form is used to garner feedback, comments, and suggestions for the terms listed in the Glossary. Please identify the term and its associated number before providing feedback. You can provide feedback for as many terms as you would like, but please only provide feedback for one term per feedback form. The MOBI team will read and review all feedback and make updates accordingly.

A

A1. Access Certificates – Access Certificates (ACs) are documents providing the ability for a particular entity to access a particular endpoint in the network’s data layer.

A2. Accessor – An entity is an Accessor of a resource if it attempts to access the URI endpoint. An Accessor may need to go through security and authentication processes in order to actually access said endpoint.

A3. Agent (Cloud-Agent, Software-Agent) –  A software component that is able to control an entity’s digital wallet (to an extent that is typically defined by the entity) and the communication to other agents in order to send or obtain information stored in the digital wallet. The agent software can be deployed on an edge device or server that is run by the entity itself or a service provider on behalf of that entity.

A4. Allow List – A list that specifies entities that are allowed to access a particular resource.

B

B1. Binding – It is often desirable to establish an additional binding of credentials to the subject that they refer to (in general there is a distinction between the entity that has the credential in their wallet – the holder – and the entity whose attributes and permissions are described by a VC – the subject.) Binding methods include using secure hardware that protects a secret key where the associated public key is referenced in a verifiable credential.

B2. Block List – A list that specifies entities that are not allowed to access a particular resource.

B3. Blockchain – A blockchain is a growing list of records, called blocks, that are linked using cryptography. Each block contains a cryptographic hash of the previous block, a timestamp, and transaction data (generally represented as a cryptographically secure tree structure such as a Merkle tree). 

C

C1. Certificate of Conformity – A CoC or Certificate of Conformity is a declaration of conformity with the type approval of the European community. It ensures the free movement of vehicles within the European Union, specifically for those vehicles that are subject to homologation or registration.

C2. Credential Issuance – Credential issuance describes the process by which an authority (“issuer”) creates and transfers (“issues”) a VC to a holder in bilateral communication. This requires different communication steps to include and verify associated data. Consequently, credential issuance is frequently preceded by a verifiable presentation in which the prospective holder convinces the issuer of their eligibility.

D

D1. Data and Functional Interoperability – Data interoperability addresses the ability of systems and services that create, exchange and consume data to have clear, shared expectations for the contents, context and meaning of that data.

D2. Data Bucket – A logical data abstraction for a persistent data store. Data written to a Data Bucket can be used repeatedly over time.

D3. Data Exchange – Data exchange is the process of taking data structured under a source schema and transforming it into data structured under a target schema, so that the target data is an accurate representation of the source data. Data exchange allows data to be shared between different computer programs.

D4. Data Host – A Data Host is an entity that stores data and is trusted with properly administering it, authenticating requests to access the data, and distributing the data as needed.

D5. Data Host Bootstrap Certificate – The Data Host Bootstrap Certificate (DBC) is a certificate that provides a cryptographic proof that a particular entity (Data Host) is allowed to serve a particular type of data from a specific URI.

D6. Data Marketplace – Decentralized data marketplace or exchange is a network run on a secure, smart contract blockchain that enables users to restore control over their data and monetize data assets without relying on a centralized platform.

D7. Data Owner – The Data Owner is the owner of a certain piece of data, usually the same as the entity that generated said data (referred to as the Data Generator).

D8. Data Stream – A logical data abstraction for data buffers. Acts as an ephemeral “stream” of data and persists for a set period of time in the network until it is purged in the online systems, thereafter, moved to nearline data systems and ultimately moved to offline data systems.

D9. Decentralized Identifier – W3C Decentralized Identifier (DID) represents a globally unique identifier that can be resolved to a DID Document, or de-referenced on a specific distributed ledger network, much like a URL on the Internet.

D10. Decentralized Storage System (DSS) – A DSS is a non-static collection of data storage nodes with a global identifier where each node typically consists of a set of object revisions (“commits”) which each represent a change (creation, update, or deletion) of a single node object. Each commit is signed, immutable, and content-addressable (typically stored and referenced by its hash). The set of commits representing an object is generally append-only, with certain exceptions made, for example, to allow garbage collection of older commits. Objects are associated with a permissioning structure (read/write) controlled by one or more DSS users. The set of data storage nodes utilizes a replication protocol that is deterministic and eventually consistent.

D11. DID Document – A DID Document is a simple text document that describes how to use that specific DID. Each DID Document may contain at least three things: proof purposes, verification methods, and service endpoints. A DID Document can specify that a particular verification method, such as a cryptographic public key or a pseudonymous biometric protocol, can be used to verify a proof that was created for the purpose of authentication. Service endpoints enable trusted interactions with the DID controller.

D12. Digital Wallet – A software application that runs, for example, on a user’s mobile phone, a laptop, server, or on a vehicle’s hardware. A digital wallet contains private keys that can be used to encrypt messages, prove control over a DID, permissions or property on a distributed ledger, or eligibility to use a VC. A digital wallet typically also contains VCs. If binding is relevant, a digital wallet can also contain a link secret or similar constructions that should never leave the wallet in unblinded form. Frequently, digital wallets also contain information about (private) peer-to-peer connections with and references of other entities in the digital identity ecosystem.

D13. Distributed Ledger Technology – Distributed Ledger Technology (DLT) enables consensus about the state of replicated, shared, and synchronized digital data geographically spread across multiple sites, countries, or institutions. A peer-to-peer network is required as well as consensus algorithms to ensure replication across nodes is undertaken. Blockchains are the most well-known example, though general practical byzantine fault tolerant systems fall under this category as well.

E

E1. Entity Identifier (EID) – An Entity Identifier (EID) is a unique alphanumeric string that uniquely identifies any entity within the system network described in this document.

E2. Engine Serial Number – The Engine Serial Number (ESN) is a unique number that identifies (within the context of a known manufacturer) an engine block.

E3. Entity – An entity (e.g. vehicle, corporation, individual, etc.) is a network participant that interacts with the system by reading/writing data, enforcing permissioning, or otherwise supporting the network in some way. An entity is identified using an entity certificate anchored on a DLT.

E4. Entity Certificate – An Entity Certificate (EC) is the certificate that represents all of a particular entity’s network-level information and metadata, including but not limited to identifiers about who they are, the URIs to delegate trust to, and their public keys. An EC is always paired with a corresponding EID.

E5. Entity Identifier – An Entity Identifier (EID) is a unique alphanumeric string that uniquely identifies any entity within the system network.

G

G1. Governance – Administrator for users, roles and certificate/UVI.

G2. Group Permission Change Certificate – Group Permission Change Certificates (GPCs) are certificates signed by a data owner prompting a Data Host to change the permissioning information of the group.

I

I1. Identity – Identity is a combination of one or more unique identifiers having meta-data associated with them. Identity meta-data consists of certificates such as verifiable credentials (per the W3C definition) and other non-verifiable data objects associated with the unique identifier(s).

I2. Intersection Movement Assistance (IMA) – IMA warns a driver if another vehicle is running a red light or making a sudden turn when approaching an intersection.

K

K1. Key Value Store – A Key-Value Store (KV Store) is a system that stores (key, value) pairs. The key is used to obtain access to the value in some way. Distributed KV stores are KV stores spread across multiple machines and can effectively maintain a global state table.

K2. Know Your Customer – Know Your Customer (KYC) is the process of verifying the identity, risks, and other information associated with a customer before initiating any business relationship.

L

L1. Left Turn Assistance (LTA) – Potential collisions with oncoming traffic while turning left belong to the most safety-critical situations accounting for ~25% of all intersection crossing path crashes. A Left Turn Assist (LTA) was developed to reduce the number of crashes. 

L2. LiDAR – Front crash prevention systems use various types of sensors, such as light detection and ranging (LiDAR), to detect when the vehicle is getting too close to one in front of it. 

M

M1. Mobility Infrastructure – Mobility infrastructure consists of physical components and software that enable greater use of mobility as a service.

M2. Mobility Service Provider – A Mobility Service Provider delivers door-to-door transportation service needs as a single entity.

M3. Mobility Services – Transportation services from public and private transportation providers.

N

N1. Network – A group of entities that all participate in a digital system, generally with a specific goal in mind. Ex: A group of entities that participate in a distributed ledger such as Ethereum.

N2. Node – A node on the system network which is maintained by affiliates. A large number of nodes is meant to provide network availability and prevent collusion attacks.

O

O1. Original Equipment Manufacturer – An Original Equipment Manufacturer (OEM) is an organization that makes devices from component parts either made internally or sourced from other organizations.

P

P1. Peer-to-Peer (P2P) – P2P refers to a collection of use cases that focus on direct energy exchange between energy peers in a decentralized manner.

P2. Personally Identifiable Information (PII) – PII is any information: (1) that identifies or can be used to identify, contact, or locate the person to whom such information pertains, (2) from which identification or contact information of an individual can be derived, or (3) that is or might be directly or indirectly linked to a natural person [ISO/IEC 29100:-1].

P3. Proof Creation – In a Verifiable Presentation, based on a proof request, the prover searches references (VCs or addresses of DLT transactions/smart contracts) in their digital wallet that allow them to present their attributes or permissions, together with a proof of their validity. This proof might be derived from one or several VCs in the prover’s digital wallet, the correctness of which can be verified based on the issuer’s signature on it, or the address of a DLT smart contract or transaction that testifies the claim.

P4. Proof Request – In a Verifiable Presentation, the verifier typically tells the prover at the start of the interaction which information they need, and what kind of proof they expect (a positive list of issuers that the verifier trusts, restrictions regarding the timeliness of a proof of non-revocation). 

P5. Proof Transmission – In a Verifiable Presentation, after creating the proof, the holder sends it as a message to the verifier. The proof might be a Zero-Knowledge Proof derived via selective disclosure from one or several VCs, or a plaintext presentation of a VC that the holder has in their wallet, or a DLT transaction or smart contract address on a distributed ledger that the verifier can read and trust.

P6. Proof Verification –  In a Verifiable Presentation, the verifier checks the correctness of the proof based on the requirements that they previously stated in the proof request and the proof that the prover sends. This can involve one or multiple read operations on a DLT or another verifiable data registry.

R

R1. Registration Certificate (Vehicle Registration Document, Part I) – The registration certificate or vehicle registration document gives the driver the official permission to participate in road traffic with the vehicle. The document contains information about the owner and the vehicle, such as the owner’s name, the date of its manufacture, and the engine and chassis numbers. The registration certificate must always be carried by the driver and must be available at a traffic stop. In this way, the vehicle can be identified. A registration certificate is required for all vehicles subject to registration.

R2. Registration Certificate (Vehicle Title Document, Part II) – The vehicle owner is referenced in the registration certificate part II (Vehicle Title Document). In some legislations, it also indicates ownership of the vehicle. If the vehicle is financed (credit/leasing), the VTD typically remains with the lender.

R3. Revocation – When entities use VCs or entries of a DLT to prove their claims in a VP, there must be a means to disable their capability to create proofs from this when the reason why the issuance had happened ceases to be legitimate. For example, a driver’s license should be revoked when its holder was caught driving drunk. Similarly, it might be useful to revoke some registration or other documents of vehicles that are reported stolen.

R4. Revocation Certificate – Revocation Certificates (RC) revoke AC permissions if the AC has not expired automatically.

R5. Role – Roles regulate creation of and access to data contained within the network.

S

S1. Secure Sockets Layer – Secure Sockets Layer is the standard security technology for establishing an encrypted link between a web server and a browser. This link ensures that all data passed between the web server and browsers remain private and integral.

T

T1. Tokenized Carbon Credits (TCC) – This refers to a collection of use cases that center around digitizing carbon credits for ease of transfer, auditability, etc. In particular, TCCs are digital, tradable certificates or permits that represent the right to emit a specified amount of greenhouse gases.

T2. Transmission Serial Number (TSN) – The Transmission Serial Number (TSN) is a unique number that identifies (within the context of a known manufacturer), a transmission unit.

T3. Transport Layer Security – The Transport Layer Security protocol is the successor of SSL and aims primarily to provide privacy and data integrity between two or more communicating computer applications.

T4. Trust Anchor – An authoritative entity that validates and qualifies entities on the network specific to the entity’s corresponding role.

U

U1. Uniform Resource Identifiers (URIs) –  Uniform Resource Identifiers (URIs) ensure that a named URI will always point to the same resource it was assigned to. Note that this is similar to the addressing system on many blockchain platforms and represents one way to implement a URI.

U2. Unique Vehicle Identifier (UVI) – A unique vehicle identifier (UVI) is a unique alphanumeric identifier within the system described in this standard. Note that a unique vehicle identifier is not the same concept as a VID.

U3. Universally Unique Identifiers (UUIDs) – Universally Unique Identifiers (UUIDs) are unique identifiers that are associated with pieces of digital information and can be used to address and identify them.

U4. URL – A specific type of URI referencing web resources.

V

V1. Vehicle Birth Certificate (VBC) – A Vehicle Birth Certificate (VBC) is a data structure of strings and integers that records information about a particular vehicle at its creation.

V2. Vehicle Identity (VID) – A Vehicle Identity (VID) comprises of a UVI and its associated data (VBC being one source of this data).

V3. Vehicle Registration Workflow – The process of (digitally) registering a vehicle through interaction of a vehicle (and typically other stakeholders such as the vehicle dealer or owner) with an authority.

V4. Vehicle-to-Grid (V2G) – V2G refers to a collection of use cases that center around the coordinated, either uni- or bi-directional energy exchange between vehicles and the grid.

V5. Verifiable Credential – The W3C Verifiable Credentials Standard defines Verifiable Credentials as “a part of our daily lives; driver’s licenses are used to assert that we are capable of operating a motor vehicle, university degrees can be used to assert our level of education, and government-issued passports enable us to travel between countries. This specification provides a mechanism to express these sorts of credentials on the Web in a way that is cryptographically secure, privacy respecting, and machine-verifiable.”

V6. Verifiable Data Registries – An abstraction of databases whose content is considered reliable and trustworthy by a large subset of stakeholders. A verifiable data registry might be a GitHub repository if GitHub is considered reliable and trustworthy by the involved stakeholders, or an Interplanetary File System (IPFS). Typically, a verifiable data registry will require strong integrity guarantees and timestamps, so blockchains or other distributed ledgers are an exceptional example of verifiable data registries.

V7. Verifiable Presentation – In many interactions, it is necessary for an entity (the prover) to convince the counterparty (the verifier) of the validity of statements regarding some of their attributes, so-called claims. Sometimes, trust with respect to the counterparty is sufficient to be convinced. However, there are many situations, in particular when there is only little or no trust between the parties, that a proof of the validity of the claims needs to be given. In the analog world, a VP would consist of showing evidence in the form of documents (signed diploma) or plastic cards (containing, e.g., watermarks or crypto-chips) that are difficult to duplicate and manipulate. In the digital world, this usually employs methods from cryptography. A verifiable presentation consists of the following sequential steps: proof request, proof creation, proof transmission, and proof verification. 

V8. VIN – A unique code, including a serial number, used by the automotive industry to identify individual motor vehicles, towed vehicles, motorcycles, scooters and mopeds, as defined in ISO 3779 (content and structure).