Glossary of Blockchain Terms

 Andrew Isikuru

Glossary of Blockchain Terms 2.0 that is now available in 6 languages. 

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ABI (Application Binary Interface)
An interface between two binary program modules, often one program is a library and the other is being run by a user


Any cryptocurrency that exists as an alternative to bitcoin

Application programming interface (part of a remote server that sends requests and receives responses)


The first, and most popular, cryptocurrency based off the decentralized ledger of a blockchain

Blockchain (Public)
A mathematical structure for storing digital transactions (or data) in an immutable, peer-to-peer ledger that is incredibly difficult to fake and yet remains accessible to anyone.

Business logic layer
A part of code that determines the rules to be followed when doing business

Business network card
Provides necessary information for a user, entity or node to connect a blockchain business network


Consensus algorithm that combines proof of work and proof of stake. Ethereum is going to use casper as a transition to proof of stake.

CDN (Content Delivery Network)
Allows for a quick transition of assets needed to load internet content (html, js, css, etc.)

Maintained by a central, authoritative location or group

A program that initializes and manages a ledgers state through submitted applications.  It is the Hyperledger Fabric equal to Smart Contracts

Representation of a digital asset built on a new blockchain

Composer CLI
Hyperledger Fabric command line allowing for administrative tasks

Composer Rest Server
Generates a rest server and associated api from a deployed blockchain

When a majority of participants of a network agree on the validity of a transaction


Cryptographic Hash Function
A function that returns a unique fixed-length string. The returned string is unique for every unique input. Used to create a “digital ID” or “digital thumbprint” of an input string.


Decentralized Applications

A decentralized autonomous organization is an organization that is run through rules encoded as computer programs called smart contracts.

DDos Attacks    

A denial-of-service attack is a cyber-attack in which the perpetrator seeks to make a machine or network resource unavailable to its intended users by temporarily or indefinitely disrupting services of a host connected to the Internet.

The concept of a shared network of dispersed computers (or nodes) that can process transactions without a centrally located, third-party intermediary.

Digital Asset    
Any text or media that is formatted into binary source

Digital signature    
A mathematical scheme used for presenting the authenticity of digital assets

Distributed Ledger
A database held and updated independently by each participant (or node) in a large network. The distribution is unique: records are not communicated to various nodes by a central authority,


Short for ‘enumeration’ - a fixed list of possible values. The list of US states could be considered an enum.

Externally Owned Account

Ethereum request for comments standard

Blockchain application that uses a built-in programming language that allows users to build decentralized ledgers modified to their own needs. Smart contracts are used to validate transactions in the ledger.


Alters the blockchain data in a public blockchain.


Gas (Ethereum)    
Measures how much work an action takes to perform in ethereum

Genesis Block    
The initial block within a blockchain.

A web based hosting service for version control using git

Golang (Google language)     
Created by google in 2009 golang is a programming language based on c

Gossip Protocol    
A gossip protocol is a procedure or process of computer-computer communication that is based on the way social networks disseminate information or how epidemics spread. It is a communication protocol.

The administration in a blockchain company that decides the direction of the company


Hard Fork    
Alters the blockchain data in a public blockchain. Requires all nodes in a network to upgrade and agree on the new version.

Hash function    
A function that maps data of an arbitrary size

Started by the Linux Foundation, Hyperledger is an umbrella project of open source blockchains

Hyperledger Composer     
Hyperledger Composer is Blockchain Application Development framework which simplify the blockchain application development on Hyperledger Fabric

Hyperledger Fabric    
Hyperledger project hosted by Linux which hosts smart contracts called chaincode


IDE (Integrated development Environment)    
Application for sofware developers that primarily consists of a source code editor, build automation tool, and debugger

“unable to be changed” Data stored in a blockchain is unable to be changed.(not even by administrators)  

Initial Coin Offering (ICO)    
The form in which capital is raised to fund new cryptocurrency ventures. Modeled after an Initial public offereing (IPO). Funders of an ICO recieve tokens.

To provide an instance of or concrete evidence in support of (a theory, concept, claim, or the like).

A function, quantity, or property that remains unchanged when a specified transformation is applied.

Inter Planetary File System





Merkle Tree    
A tree in which every leaf node is labelled with the hash of a data block and every non-leaf node is labelled with the cryptographic hash of the labels of its child nodes.

The act of validating Blockchain transactions. Requires computing power and electricity to solve “puzzles”. Mining rewards coins based on your computing power

Mining pool    
A collection of miners who come together to share their processing power over a network and agree to split the rewards of a new block found within the pool.

Browser for installing and using Dapps

MSP (Membership Service Provider)     
A Hyperledger Fabric blockchain network can be governed by one or more MSPs


A copy of the ledger operated by a user on the blockchain

A number only used once in a cryptographic communication (often includes a timestamp)

Nothing at Stake problem    
This is caused by validator nodes approving all transactions on old and new software after a hard fork occurs

NPM (Node Package Manager)    
Default package manager runtime environment node.js. NPM manages dependencies for an application


Oauth protocol    
Open Authorization is a standard that is used by third party services to keep and distribute users information without exposing their password

Ommer (aka Uncle)    
A block which has been completely mined but has not yet been added to the Blockchain.

On-chain governance    
A system for managing and implementing changes to a cryptocurrency blockchain

An agent that finds and verifies real-world occurrences and submits this information to a blockchain to be used by smart contracts.

Orderer Network    
A computer network that allows nodes to share resources.


P2P (Peer to Peer)    
Denoting or relating to computer networks in which each computer can act as a server for the others, allowing shared access to files and peripherals without the need for a central server

PKI (Public Key Infrastructure)     
A set of roles, policies, and procedures needed to create, manage, distribute, use, store, and revoke digital certificates and manage public-key encryption.

Pragma(s) or Pragma-line    
Defines which compiler version the smart contract uses

Private Blockchain    
Blockchain that can control who has access to it. Contrary to a public blockchain a Private Blockchain does not use consensus algorithms like POW or POS, instead they use a system known as byzantine fault tolerant(BFT). BFT is not a trustless system which makes a BFT system less secure.

Proof of Activity    
Active Stakeholders who maintain a full node are rewarded

Proof of Burn    
Miners send coins to an inactive address essentially burning them. The burns are then recorded on the blockchain and the user is rewarded.

Proof of Capacity    
Plotting your hard drive (storing solutions on a hard drive before the mining begins). A hard drive with the fastest solution wins the block

Proof of elapsed time    
Consensus algorithm in which nodes must wait for a randomly chosen time period and the first node to complete the time period is rewarded

Proof of Stake (POS)    
A consensus algorithm that chooses the owner of a new block based on the wealth they have or (Stake). There is not a block reward so the forgers take the transaction fee.

Proof of Work (POW)    
A consensus algorithm which requires a user to “mine” or solve a complex mathematical puzzle in order to verify a transaction. “Miners” are rewarded with Cryptocurrencies based on computational power.


Public key cryptography    
Encryption that uses two mathematically related keys. A public and private key. It is impossible to derive the private key based on the public key.



REST API (representational state transfer API)    
Defines restraints based on http

RPC (Remote Procedure Calls)     
A protocol that is used from one program to request a service on another program located on a network


A software development kit provides the necessary tools for a developer to create software on a specific platform

Dividing a blockchain into several smaller component networks called shards capable of processing transactions in parallel.

Smart Contract    
Self executing contract with the terms of agreement written into the code

Solidity is a contract-oriented programming language for writing smart contracts. It is used for implementing smart contracts on various blockchain platforms.


Representation of a digital asset built on an existing blockchain

Turing Complete language    
A language that is able to perform calculations that a computer is capable of


Free open source operating system and linux distribution

UTXO (Unspent Transaction Outputs)     
Unspent transaction outputs are used to determine whether a transaction is valid


A programming language created to be a formal introduction to smart contracts


Stores the digital assets you own.




Zeppelin (or Open Zeppelin)    
Community of like minded Smart Contract developers


51% Attack
A situation in which a majority of miners in the blockchain launch an attack on the rest of the nodes (or users). This kind of attack allows for double spendig