Asset

Anything that has value to a stakeholder.

Block

Data structure comprising a block header and block data.

Blockchain

Specific type of DLT.
Database which is:

• distributed
• append-only
• organized in sequential blocks:
  • chained together using cryptographic links
  • whose content is made by consensus

Blockchains are designed to be tamper resistant and to create final, definitive and immutable ledger records.

Block data

Data structure comprising zero or more transaction records or references to transaction records.

Block header

Data structure that includes a cryptographic link to the previous block.

Confirmed

Accepted by consensus for inclusion in a distributed ledger.

Consensus

Agreement among nodes that:

1. a transaction is validated
2. the distributed ledger contains a consistent set and ordering of validated transactions

Consensus does not necessarily mean that all nodes agree.
The details regarding consensus differ between blockchain designs and this is one key distinguishing characteristic between one design and another.

Consensus mechanism

Rules and procedures by which consensus is reached.

Cryptographic hash function

Function mapping binary strings of arbitrary length to binary strings of fixed length, such that it is computationally costly to find for a given output an input which maps to the output, and it is computationally infeasible to find for a given input a second input that maps to the same output
Computational feasibility depends on the specific security requirements and environment.

Cryptographic link

Reference, constructed using a cryptographic hash function technique, that points to data.
A cryptographic link is used in the block header to reference the previous block in order to create the append-only, sequential chain that forms a blockchain.

Distributed Ledger (also called distributed ledger technology: DLT)

Ledger that is shared across a set of nodes and synchronized between the nodes using a consensus mechanism.

Immutability

Property wherein ledger records cannot be modified or removed once added ("append-only") to a distributed ledger.
Where appropriate, immutability also presumes keeping intact the order of ledger records and the links between the ledger records.

Node

Device or process that participates in a network and stores a complete or partial replica of the ledger records.

Ledger

Information store that keeps records of transactions that are intended to be final, definitive and immutable

Ledger record

Record comprising hashes of transaction records or references to transaction records recorded on a blockchain or distributed ledger system.

Public Key

Key of an entity's asymmetric key pair which can be made public.

Private key

Key of an entity's asymmetric key pair that is kept secret and which should only be used by that entity.

Record

Information created, received and maintained as evidence and as an asset by an organization or person, in pursuit of legal obligations or in the transaction of business.
Applies to information in any medium, form or format.

Transaction

Smallest unit of a work process, which is one or more sequences of actions required to produce an outcome that complies with governing rules.
Where appropriate, transaction is understood more narrowly, as the smallest unit of a work process related to interactions with blockchain or distributed ledgers.

Transaction record

Record documenting a transaction of any type.
Transaction records can be included in, or referred to, in a ledger record.
Transaction records can include the result of a transaction.

Validated

Status of an item when its required integrity conditions have been checked.
A transaction, ledger record or a block can be validated.

Wallet

Application used to generate, manage, store or use private and public keys.