Blockchain Glossary

Everything you want to know, but are too afraid at this point to ask. 

A

Address

A secure identifier marked by a unique string of characters that enables payments to an individual or entity via blockchain transactions, usually requiring a private key to exclusively access the funds. For example, Bitcoin addresses are alphanumeric strings that begin with a 1 or 3; Ethereum addresses begin with ‘0x’.

Airdrop

A procedure of distributing tokens by awarding them to existing holders of a particular blockchain currency, such as Bitcoin or Ethereum; frequently used as a marketing strategy.

Altcoin

A cryptocurrency or a category of cryptocurrencies that are an alternative to Bitcoin.

API

Application Programming Interface. A set of subroutine definitions, protocols and tools for building software and allowing communications between components.

APpcoin

A coin or token specifically designed for use in a dApp or smart contract. Appcoins are deployed on a protocol blockchain that supports non-native tokens such as Ethereum and are typically structured as utilities.

Application-specific Integrated Circuit (ASIC)

A microchip designed for a special application. In the context of blockchain, ASICs are used for energy- and cost-efficient mining.

Atomic Swap

A smart contract technology that enables the trustless exchange of one cryptocurrency for another without the need for a third party. Atomic swaps can be conducted between blockchains of different cryptocurrencies or off-chain.

B

Bitcoin Cash (BCH)

Refers to a collection of data related to transactions that are bundled together with a predetermined size and are processed for transaction whereby it becomes part of a blockchain. For more information, visit the website or read the white paper.

Bitcoin (BTC)

A cryptocurrency created by Satoshi Nakamoto in 2009. It was the first digital currency that enabled instant P2P payments. Bitcoins are created through a process known as mining which requires a massive amount of computing power. For more information, visit the website or read white paper.

Block

Refers to a collection of data related to transactions that are bundled together with a predetermined size and are processed for transaction whereby it becomes part of a blockchain.

Block Explorer

An online tool to view all transactions on a given blockchain.

Blockchain

A decentralized and immutable digital ledger where cryptocurrency transactions are recorded chronologically and publicly.

Block Header

An 80-byte header belonging to a single block which is hashed repeatedly to create Proof-of-Work, resulting in verified transactions, block rewards, and a new block.

Block Height

The number of blocks preceding a particular block (or transaction) on a blockchain.

Block Reward

The tokens or coins earned by a miner or mining pool as a result of a mining a block.

Byte Code

Code compiled to run on a virtual machine.

Byzantine Fault Tolerance

Byzantine fault tolerance is the resistance of a fault-tolerant computer system, particularly distributed computing systems, towards electronic component failures where there is imperfect information on whether a component is failed. “Failure” could refer to intentional attacks or lack of network connection. 

C

Chain Linking

The process of connecting two blockchains, allowing the exchange of assets between them.

Circulating Supply

The number of coins or tokens that are circulating in the public market. See also: Total Supply and Maximum Supply.

Cloud Mining

The process of mining via a remote datacenter contracted through the owner of the hardware, allowing users to mine cryptocurrency without having to own or manage hardware. Cloud mining has low returns compared to traditional mining, but requires significantly less effort.

Coin

Tokens that serve solely as digital cash, acting as unit of account and a medium of exchange. See also: Equity Token, Security Token, Token, Utility Token.

Consensus Protocol

The process by the nodes (or computers) in a network reaching agreement about which blocks of data go onto the blockchain.

Cryptocurrency

A digital currency that is generally decentralized and uses cryptography for additional security, making it difficult to counterfeit or manipulate.

Cryptojacking

The secret use of a device to mine cryptocurrency, typically using in-browser mining software.

Cryptographic Hash Function

A piece of code that encrypts data into a hash.

Cryptography

The study of writing or solving codes and ciphers.

D

Dark Wallet

A digital wallet that enables data anonymization by obfuscating transactions carried out in the online market space using an intermediary wallet.

Dash (DASH)

A type of cryptocurrency based on Bitcoin software but has anonymity features that makes it impossible to trace transactions to an individual and other capabilities. It was created by Evan Duffield in 2014 and was previously known as XCoin (XCO) and Darkcoin. For more information, visit the website, read the white paper, or read the original Darkcoin white paper.

Decentralization

A state where there is no central control, power, or function, and no central point of infrastructural failure. See Vitalik Buterin’s definition of decentralization.

Decentralized Application (dApp)

A type of software program that runs on a decentralized P2P network rather than on a single computer. Although similar, it differs from smart contracts as it can have any number of participants on all sides of the market and it does not have to be financial. Ethereum is a popular development platform for creating dApps. For more information, see Vitalik Buterin’s terminology guide.

Decentralized Autonomous Organization (DAO)

Self-governing entities that run on a blockchain without human intervention. All operations are hard-coded into the DAO itself.

Decentralized Exchange (DEX)

An exchange structure that consists of a network of various technical devices that enable investors to create a marketplace without a centralized location such as a server.

Delegated Proof-of-Stake

An algorithm that achieves distributed consensus by using delegated stakeholder approval voting to resolve consensus issues and validate the blockchain in a model with similar designs to democratic systems. Best known for its use on the EOS blockchain.

Denial-of-service Attack (DoS Attack)

An attack cause by a malicious actor flooding a targeted network with traffic until the target cannot respond, preventing access for legitimate users. See also: Distributed Denial-of-service Attack (DDoS Attack), Sybil Attack, 1 Percent Attack, 33 Percent Attack, 51 Percent Attack.

Derivative

A contract between two or more parties that is a financial security with a value that is derived from an underlying asset. Also referred to as a ‘Financial Derivative’ or ‘Derivative Contract’.

Difficulty

The relative ease with which a block can be mined.

Directed Acyclic Graph (DAG)

In Distributed Ledger Technology and mathematics: a data structure of connected nodes where all nodes are directed from one to another in topological order. Sometimes referred to as a Tangle, and most famously used by IOTA.

Distributed Consensus

Collective agreement by various computers in a network and allows it to work in a decentralized, Peer-to-peer manner without the need of central authority to deter dishonest network participants.

Distributed Denial-of-service Attack (DDos Attack)

An attack (similar to a denial-of-service attack) occuring when multiple machines operate together to attack a single target, increasing the difficulty of attribution and allowing for exponentially more requests to be sent to the target. See also: Sybil Attack, 1 Percent Attack, 33 Percent Attack, 51 Percent Attack.

Distributed Ledger Technology (DLT)

A system, most commonly a blockchain, for creating a shared, cryptographically secured database.

Double Spending

In blockchain: the result of successfully spending a coin or token more than once.

E

EOS (EOS)

The native cryptocurrency of the EOS blockchain: a Turing-complete blockchain created by block.one in 2018 with the intent to solve the scaling issues present on the Ethereum blockchain. EOS attempts to achieve scalability through its ability to run on multiple computer cores and a delegated proof-of-stake consensus algorithm. For more information, visit the website or read the white paper.

Equity Token

A subcategory of security tokens that represent ownership of an asset, such as debt or company stock. See also: Coin, Security Token, Token, Utility Token.

Ethereum Request for Comments (ERC)

A subcategory of security tokens that represent ownership of an asset, such as debt or company stock. See also: Coin, Security Token, Token, Utility Token.

ERC20

A token standard for Ethereum which ensures the tokens perform in a predictable way. This allows the tokens to be easily exchangeable and able to work immediately with decentralized applications that also use the ERC20 standard. Most tokens released through ICOs are compliant with the ERC20 standard.

Functions:

  • Total Supply: Returns total token supply
  • Balance: Returns balance of tokens in the owner account
  • Allowance: Returns amount which spender is still allowed to withdraw from owner
  • Transfer: Transfers token to a specified address
  • Approve: Allows spender to withdraw a specified amount of tokens from contract
  • Transfer From: Transfers tokens from source to destination address

Events:

  • Transfer: Triggered whenever tokens are transferred
  • Approval: Triggered on any call to approve
ERC223

A token standard for Ethereum which uses the token fallback parameter to prevent ERC20 tokens sent mistakenly to smart contracts not intended to work with Ether becoming lost forever.

ERC621

Another extension of the ERC20 Standard that aims to add two new functions: increaseSupply and decreaseSupply.

ERC721

A token standard for Ethereum which describes non-fungible tokens on the Ethereum blockchain. Used for tokenizing or creating unique assets.

ERC777

The ERC777 standard defines a new way to interact with a token contract while remaining backward compatible with ERC20. It defines advanced features to interact with tokens. Namely, operators to send tokens on behalf of another address — contract or regular account — and send/receive hooks to offer token holders more control over their tokens.

It takes advantage of ERC820 to find out whether and where to notify contracts and regular addresses when they receive tokens as well as to allow compatibility with already-deployed contracts.

ERC827

An extension of ERC20 Standard, ERC827 Standard allows for the transfer of tokens and allows tokens to be spent by third parties as long as the holder approves it. This is particularly useful when tokens may need to be re-used by other applications such as wallets and dexs.

ERC865

ERC865 intends to allow for token transfers to pay using the native token instead of using Ether for gas, in one transaction. The standard intends for a user to send tokens to a third party who pays for gas and takes a fee in tokens.

ERC884

An ERC Standard aims to create an ERC20 token that conforms to the Delaware State Senate for shares issued by a Delaware Corporation. Each ERC884 token is intended to represent equity issues by any Delaware Corp, private or public.

The token contract must provide the following three functions of a Corporation’s Stock Ledger:

  • It must enable the corporation to prepare the list of shareholders specified in Sections 219 and 220 of The Act
  • It must record the information specified in Sections 156, 159, 217(a) and 218 of The Act
  • It must record transfers of shares as governed by Article 8 of Subtitle I of Title 6
ERC918

A mineable ERC20 token which aims to create a Bitcoin-like token on top of the Ethereum platform. The specification calls for locking up tokens initially into a smart contract and slowly dispensing them with a mint function which acts like a faucet. The mint function would use a Proof-of-work algorithm in order to minimize gas fees and control the distribution rate.

ERC998

ERC998 is an extension for any non-fungible token to own other non-fungible ERC721 or ERC20 tokens. Transferring the token composition means transferring the entire hierarchy of items. For example, a CryptoKitty may own a scratching post and a feeding dish; the dish may contain some amount of fungible cat food tokens.

Ether (ETH)

A cryptocurrency used for operating the Ethereum platform and is used to pay for transaction fees and computational tasks. In the platform, transaction fees are measured based on the gas limit and gas price and ultimately paid for in Ether. For more information, visit the website or read the white paper.

Ethereum

An open source, decentralized platform based on blockchain technology created by Vitalik Buterin in 2013. It runs smart contracts on a custom built blockchain that allows developers to create markets, store registries of debts and so on. For more information, visit the Ethereum Foundation website or read the white paper.

Ethereum Classic (ETC)

A cryptocurrency that is a continuation of the original Ethereum blockchain following the DAO attack in June 2016. Ethereum is a hard fork of the blockchain that was formed to refund the Ether that was siphoned during the attack. Ethereum Classic assumes no hard fork occurred and is supported by those who believe in complete immutability of the blockchain. For more information, visit the website or read the white paper.

Ethereum Virtual Machine (EVM)

A cryptocurrency that is a continuation of the original Ethereum blockchain following the DAO attack in June 2016. Ethereum is a hard fork of the blockchain that was formed to refund the Ether that was siphoned during the attack. Ethereum Classic assumes no hard fork occurred and is supported by those who believe in complete immutability of the blockchain. For more information, visit the website or read the white paper.

F

Fiat

Refers to currencies that have minimal or no intrinsic value themselves (i.e. they are not backed by commodities like gold or silver), but are defined as legal tender by the government, such as paper bills.

Fork
Fractional Reserve System

The monetary policy at the basis of the modern banking system. Under FRS, banks are required to hold only a fraction of the depositors’ funds as cash reserves. The remaining 88 percent of deposited funds can be loaned out to create new deposits which in turn create new loans, exerting a multiplier effect on the total money supply.

Full Node

A client that operates on the network and maintains a full copy of the blockchain. A full node can perform the functions of a node, while also updating the blockchain with block entries and confirmations from miners. See also: Master Node, Node.

Fungibility

This property of an item to be mutually interchangeable with an identical item, such as money, gold, or oil.

G

Gas

Gas is the execution fee for every operation made on Ethereum (or similar blockchain). Its price is expressed in Ether and is decided by the miners, who prioritize transactions based on their gas prices.

Gas Limit

A term used in the Ethereum platform that refers to the maximum amount of gwei the user is willing to spend on a transaction. The transaction must have enough gas to cover the computational resources needed to execute the code. All unused gas is refunded at the end of the transaction.

Gas Price

A term used in the Ethereum platform that refers to the price you are willing to pay for a transaction. Setting a higher gas price incentivizes miners to prioritize and validate that particular transaction ahead of those set with a lower gas price. Gas prices are typically denominated in Gwei.

Genesis Block

The first block of data that is processed and validated to form a new blockchain, often referred to as block 0 or block 1.

Gwei

The unit of measurement for gas on the Ethereum network.

H

Halving

A 50 percent reduction in the block reward given to cryptocurrency miners once a certain number of blocks have been mined.

Hard Cap

The maximum amount that an ICO will be raising. If an ICO reaches its hard cap, they will stop collecting any more funds. See also: Soft Cap.

Hard Fork

A permanent divergence in the the blockchain, commonly occuring when non-upgraded nodes can’t validate blocks created by upgraded nodes that follow newer consensus rules. See also: Soft Fork.

Hash

A digital string of characters produced by encrypting a larger piece of data.

Hashcash

A proof-of-work system used to limit denial-of-service attacks.

Hash Function

The algorithm that turns input data into a hash.

Hash Rate

Hashes per second performed by a network or miner.

Hash Tree (Merkel Tree)

In cryptography: 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, allowing efficient and secure verification of the contents of large data structures.

I

IOTA (IOT)

Refers to the cryptocurrency and the name of an open source distributed ledger founded in 2015 that does not use blockchain (it uses a new distributed ledger called the Tangle). It offers features such as zero fees, scalability and fast and secure transactions. It is focused on the Internet of Things. For more information, visit the website, read the white paper or read the FAQs.

Initial Coin Offering

A means by which a cryptocurrency venture, typically early stage, can raise money from supporters by issuing tokens. Often referred to as a crowdsale as participants may potentially earn a return on their investments (as opposed to crowdfunding, where supporters donate money to a project or cause). Ethereum is currently the most popular platform for launching ICOs.

InterPlanetary File System (IPFS)

A peer-to-peer distributed file system that seeks to connect all computing devices with the same system of files with no single point of failure.

L

Lightning Network

A low latency, off-chain P2P system for making micropayments of cryptocurrencies. It offers features such as instant payments, scalability, low cost and cross-chain functionality. Participants do not have to make individual transactions public on the blockchain and security is enforced by smart contracts. For more information, visit the official website or read the white paper.

Litecoin (LTC)

A cryptocurrency that was created by former Google employee Charlie Lee in 2011. It offers features such as Segregated Witness and the Lightning Network which allows for faster processing at lower cost. For more information, visit the website.

M

Market Capitalization

The market value of a company, market or sector at a point in time commonly used to rank relative size. In cryptocurrency investing, it refers to either token price multiplied by the circulating supply (free float market capitalization) or token price multiplied by the total supply (diluted market capitalization).

Masternode

A client that performs the functions of a full node as well as additional chain-specific functions. Master nodes are paid a portion of the block reward. See also: Full Node, Node.

Maximum Supply

An approximation of the maximum number of coins or tokens that will ever exist for a cryptocurrency or crypto asset. See also: Circulating Supply and Total Supply.

Mempool

The pool of pending transactions on a blockchain.

Merkel Tree

See Hash Tree.

Mining

A process by which transactions are verified and added to a blockchain. It is also a process by which new Bitcoins or certain altcoins are created. In theory, anyone with the necessary hardware and access to the Internet can be a miner and earn income, though the cost of industrial hardware and electricity has limited mining for bitcoins and certain altcoins today to large-scale operations.

Mining Pool

A network of miners working in conjunction to pool hashing power. Each miner typically receives a share of the block reward proportionate to their hashing power.

Monero (XRM)

A cryptocurrency created in 2014 that is focused on fungibility, privacy and scalability. Transactions on Monero are obfuscated via ring signatures and stealth addresses to be made untraceable to any particular user or real world identity. For more information, visit the website or read the white paper.

Multi-signature Wallet

An address that has functionality to require confirmation from two or more private keys to transact.

N

NEM (XEM)

Refers to the cryptocurrency and the name of a platform for management of a variety of assets, including currencies, supply chains, ownership records, etc. It offers additional features to blockchain technology such as multi-signature accounts, encrypted messaging, etc. For more information, visit the website or read the white papers and guides.

NEO (NEO)

Refers to the cryptocurrency and the name of a China’s first open source blockchain that was founded in 2014 by Da Hongfei. It is similar to Ethereum in its ability to execute smart contracts or dApps but has some technical differences such as coding language compatibility. For more information, visit the website or read the official documentation.

Network Effect/Network Externality

A phenomenon whereby increased numbers of users or participants improve the value of a good or service.

Node

In blockchain: some touchpoint that accesses a blockchain (eg: a smartphone, a server, or another computer) and is able to send and receive transactions. See also: Full Node, Master Node.

Non-Fungible Token (NFT)
A non-interchangeable type of cryptographic token which is unique. See Fungibility.
Nothing-at-stake Problem

An issue with proof-of-stake chains wherein miners stand to lose nothing by signing each and every fork.

O

Oracle

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

P

Peer-to-Peer (P2P)

A system wherein computers communicate directly, instead of through a server.

Permissioned Blockchain

A shared database with a blockchain structure that requires participants to obtain permission before reading or writing to the chain. Contrast this with permissionless blockchains which anyone can join.

Private Blockchain

A shared database with a blockchain structure that requires participants to obtain permission before reading or writing to the chain. Contrast this with permissionless blockchains which anyone can join.

Privacy Coin

A cryptocurrency that provides its users with a high level of anonymity. Common privacy coins include Monero and Zcash. See also: Ring Signature, Stealth Address, Zero-knowledge Proof.

Private Key

A secret cryptographic key used by the owner to decrypt messages intended only for them, having been previously encrypted with their public key.

Private Sale

A sale that takes place before participation in an ICO is made available to the general public, typically excluding non-accredited investors.

Proof-of-authority (PoA)

A consensus protocol in a private blockchain which gives a number of authorized clients the right to make all of the blocks in the blockchain. See also: Consensus Protocol, Distributed Consensus, Delegated Proof-of-stake (DPoS), Proof-of-stake (PoS), Proof-of-work (PoW).

Proof-of-Stake (PoS)

An algorithm that rewards participants that solve cryptographic puzzles to achieve distributed consensus. Unlike Proof of Work or ‘PoW’, a person can validate transactions and create new blocks based on their individual wealth (i.e. stake) such as the total number of coins owned. One of the key advantages that PoS has over PoW is lower energy consumption.

Proof-of-Work (Pow)

An algorithm that rewards the first person that solves a computational problem (i.e. mining) to achieve distributed consensus. Miners compete to solve difficult cryptographic puzzles in order to add the next block on the blockchain. Proof-of-work prevents spam and cyber attacks such as DDoS as it requires processing time from the service requester.

Proof-of-Work (Pow)

An algorithm that rewards the first person that solves a computational problem (i.e. mining) to achieve distributed consensus. Miners compete to solve difficult cryptographic puzzles in order to add the next block on the blockchain. Proof-of-work prevents spam and cyber attacks such as DDoS as it requires processing time from the service requester.

Protocol

In computing: A set of rules governing the exchange or transmission of data between devices.

Public Blockchain

A blockchain which any Internet-connected individual can read, transact on and participate in the consensus protocol. Public blockchains are generally considered to be “fully decentralized” once a critical mass of miners has been reached.

Public Key

A cryptographic key that can be obtained and used by anyone to encrypt messages intended for a particular recipient, such that the encrypted messages can be deciphered only by using a second key that is known only to the recipient (a private key).

R

Ring Signature

A type of digital signature that can be performed by any member of a given group of users. Ring signatures increase privacy as it is impossible to determine which member of the group signed the transaction. Most notably used by the Monero blockchain.

Ripple (XRP)

Refers to the cryptocurrency and the name of an open source payment platform where XRP can be transferred. The vision for the platform is to enable real-time global payments anywhere around the world. The Ripple payment protocol was built by OpenCoin which was founded in 2012. For more information, visit the website or read the white paper.

Ripple Payment Protocol

An open source payment platform where the cryptocurrency XRP can be transferred. The vision for the platform is to enable real-time global payments anywhere around the world. The Ripple Payment Protocol was built by OpenCoin which was founded in 2012. For more information, visit Ripple’s website.

S

Satoshi

The smallest unit of Bitcoin, equal to 0.00000001 BTC.

Satoshi Nakamoto

The person or group of people who created and released the Bitcoin protocol in 2009.

Secure Hash Algorithm (SHA)

A family of cryptographic hash functions, which includes SHA-256, published by the National Institute of Standards and Technology (NIST) as a U.S. Federal Information Processing Standard (FIPS).

Security Token
  1. A token with value derived from an external, tradable asset.
  2. A token that is subject to federal securities regulations.

See also: Coin, Equity Token, Token, Utility Token.

Security Token Offering

An offering of security tokens, similar to an ICO. See also Initial Coin Offering (ICO).

Segregated Witness (SegWit)

The process where the block size limit on a blockchain is increased by removing digital signature data and moving it to the end of a transaction to free up capacity. Transactions are split (or ‘segregated’), into two segments: the original data segment and the signature (or ‘witness’) segment.

SHA-256
Sidechain

A blockchain that is interoperable with a parent chain that uses the same cryptographic hash function, allowing tokens or coins from the sidechain to be transacted on the parent blockchain and moved back to the original blockchain if needed.

Smart Contract

An automated mechanism involving two or more parties where digital assets are put in and redistributed at a later date based on some preset formula or triggering event. The contract can run as programmed without downtime, censorship, fraud or third party interference. For more information, see Vitalik Buterin’s terminology guide.

Soft Cap

The minimum amount that an Initial Coin Offering intends to raise. If the ICO is unable to raise that amount, it may be cancelled and the collected funds returned to participants. See also: Hard Cap.

Soft Fork

A temporary divergence in the blockchain caused by non-upgraded nodes not following new consensus rules. Usually caused in order to implement new functionalities that are backwards compatible. See also: Hard Fork.

Solidity

The programming language for developing Ethereum smart contracts.

Stealth Address

A privacy feature which allows for unique and disposable addresses to be randomly-generated,

Stealth Address

A privacy feature which allows for unique and disposable addresses to be randomly-generated,

Sybil Attack

An attack wherein the attacker subverts the reputation system of a peer-to-peer network by creating a large number of pseudonymous identities, using them to gain a disproportionately large influence. See also: Distributed Denial-of-service Attack (DDoS Attack), 1 Percent Attack, 33 Percent Attack, 51 Percent Attack.

T

Token

A cryptocurrency that offers functionality over and above that of a coin, enabling the creation of open, decentralized networks and providing a way to incentivize participants in the network with both network growth and token appreciation. Made popular with the introduction of Ethereum. See also: Coin, Equity Token, Security Token, Utility Token.

Tokenomics

The sum of a token’s uses, utilities and permutations of transfers between types of entities within its native system: the macroeconomics of a token with its intended economy.

Token Swap

A token swap, also referred to as token migration, is the transferal of a cryptographic token from one blockchain onto another. Instead of trading one token for another on an exchange, each token held is replaced with a new token on the new blockchain and the old tokens become valueless.

Total Supply

The total number of coins or tokens that are currently in existence, including those circulating in the public market and those that are locked or reserved.

Trustlessness

In the context of distributed ledger technology: a feature of distributed ledgers and smart contracts which allows two or more parties to interact without needing to trust the other participants of a third-party intermediary.

Turing-Completeness

A system of data-manipulation rules that can be used to simulate any Turing machine.

U

Universal Turing Machine (UTM)

In computer science: a machine that can simulate an arbitrary machine on arbitrary input by reading both the description of the machine to be simulated as well and the input for that machine.

Unspent Transaction Output (UTXO)

The “change” that is spent and received in Bitcoin transactions. Each Bitcoin transaction begins with coins used to balance the ledger; UTXOs are processed continuously and are responsible for beginning and ending each transaction. Confirmation of transaction results in the removal of spent coins from the UTXO database, but a record of the spent coins still exists on the ledger. Ie: Each new transaction in the blockchain consumes some unspent outputs and creates others. An output is considered unspent when it has not yet been used as an input to a new transaction. All asset units on a blockchain exist in the unspent output set.

Utility Token

A token which provide users with access (or future access) to a product or service. See also: Coin, Equity Token, Security Token, Token.

V

Velocity

The speed at which a token is sold, traded, or spent. Equivalent to the total transaction volume of a network divided by the average network value.

W

Wallet

A store of digital assets such as cryptocurrencies, analogous to a digital bank account. Cryptocurrency wallets can be divided into two categories: hosted or ‘hot’ wallets (e.g. wallets store on exchanges or third-party servers) and cold wallets (e.g. hardware wallets such as the Ledger Nano Spaper wallets and desktop wallets).

Wei

The smallest denomination of Ether, equal to 0.000000000000000001 ETH.

Whitelist

In the context of an ICO: A list of registered and approved participants that are given exclusive access to contribute to an ICO or a pre-sale.

White Paper

A technical document that informs readers on the philosophy, objectives, and technology of a project or initiative. White papers are often provided before the launch of a new coin, token or blockchain.

Z

ZCash (ZEC)

A cryptocurrency with strong privacy features, that uses zero-knowledge Succinct Non-interactive Arguments of Knowledge (zk-SNARKs), a variant of zero-knowledge proofs, to provide privacy to its users. For more information, visit the website or read the original Zerocash white paper.

Zero-Knowledge Proof

A method by which one party can prove to another party that they know a given value without disclosing any information about that value. Commonly used in privacy coins to hide transaction details.

#

1 Percent Attack

An attack on a sharded proof-of-work system where an attacker can effectively achieve 100% control of a single shard by owning only 1% of the network’s hashing power. See also: Denial-of-service Attack (DoS Attack), Distributed Denial-of-service Attack (DDoS Attack), Sybil Attack, 1 Percent Attack, 33 Percent Attack, 51 Percent Attack.

33 Percent Attack

An attack on a DAG cryptocurrency network whereby an attacker is able to control 33 percent of the network’s hashrate, allowing a double spend to occur. See also: Denial-of-service Attack (DoS Attack), Distributed Denial-of-service Attack (DDoS Attack), Sybil Attack, 1 Percent Attack, 51 Percent Attack.

51 Percent Attack

An attack on a proof-of-work cryptocurrency network whereby an attacker is able to control a majority of the network’s mining power or hashrate, allowing a double spend to occur. See also: Denial-of-service Attack (DoS Attack), Distributed Denial-of-service Attack (DDoS Attack), Sybil Attack, 1 Percent Attack, 33 Percent Attack.