This glossary is intended to provide as comprehensive a list as possible of commonly used terms from the blockchain space. It includes definitions as they are commonly understood by the community.

As blockchain is a nascent technology, the spelling and formatting of many of these words have not yet been standardized by popular style guides. Moreover, as an interdisciplinary technology, blockchain makes heavy use of terminology borrowed from other fields of study. As it would be impossible to incorporate full glossaries from these fields, only some of the more commonly used words have been included.

Compound terms consisting of a noun and a preceding adjective are generally listed alphabetically under the modifier or adjective. Standard American spelling is used throughout

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.
See also: Coin, Colored Coin, Cryptocurrency, Privacy Coin, Security Token, Token, Tokenized Security, Utility Token.

 

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 blockchain that supports non-native tokens such as Ethereum and are frequently structured as utilities.

 

Application-specific Integrated Circuit (ASIC)
Circuitry 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.

 

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.

 

Blockchain 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 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.

 

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.

 

Byte Code

Code compiled to run on a virtual machine. Usually used in the context of Turing-complete blockchains.

 

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 or operating dishonestly.

 

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.

 

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.

 

Colored Coin

A class of methods for representing and managing real world assets stored as metadata on the Bitcoin blockchain.

 

Confirmation

The process by which a transaction is determined to be secure. Obtained by allowing additional data to be published to the chain before the transaction is acted upon.

 

Confirmation Number

The number of blocks that have been mined after a given transaction. For example, a transaction that was mined five blocks ago is said to have five confirmations.

 

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.

Dark Wallet

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

 

Decentralization

A state where there is no central control, power, or function, and no central point of infrastructural failure. See Vitalik Buterin’s “The Meaning 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 in it can have any number of participants on all sides of the market and its operations do 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 Byzantine Fault Tolerance (dBFT)

A consensus protocol developed by NEO to overcome the Byzantine Generals Problem. The system is comprised of nodes, delegates, and a speaker. New blocks are proposed by the speaker and confirmed by delegates, requiring a two-thirds majority for consensus.

 

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. Most 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.

 

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 that allows a network to work in a decentralized, trustless, and peer-to-peer manner without the need of a centralized authority.

 

Distributed Denial-of-service Attack (DDos Attack)

An attack (similar to a denial-of-service attack) occurring 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.

 

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.

 

Ethereum

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

 

Ethereum Request for Comments (ERC)

A proposal that outlines a standard list of rules that an Ethereum token must implement in order to comply. Common token standards are listed below.

 

ERC-20

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 ERC-20 standard. Most tokens released through ICOs are compliant with the ERC-20 standard.

Functions:
totalSupply: 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
transferFrom: Transfers tokens from source to destination address
Events:
Transfer: Triggered whenever tokens are transferred
Approval: Triggered on any call to approve

 

ERC-223

A token standard for Ethereum which uses the token fallback parameter to prevent ERC-20 tokens sent mistakenly to smart contracts not intended to work with Ether becoming lost forever.

 

ERC-621

Another extension of the ERC-20 standard that aims to add two new functions: increaseSupply and decreaseSupply.

 

ERC-721

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

 

ERC-777

The ERC-777 standard defines a new way to interact with a token contract while remaining backward compatible with ERC-20. ERC-777 defines advanced features to interact with tokens; namely, operators to send tokens on behalf of another address—smart contract or wallet—and send and receive hooks to offer token holders more control over their tokens.

ERC-777 takes advantage of ERC-820 to determine whether and where to notify contract and wallet addresses when they receive tokens as well as to allow compatibility with already deployed contracts.

 

ERC-827

An extension of the ERC-20 standard, ERC-827 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.

 

ERC-865

ERC-865 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.

 

ERC-884

An ERC standard aims to create an ERC-20 token that conforms to the Delaware State Senate for shares issued by a Delaware Corporation. Each ERC-884 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

 

ERC-918

A mineable ERC-20 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.

 

ERC-998

ERC-998 is an extension for any non-fungible token to own other non-fungible ERC-721 or ERC-20 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.

 

ERC-1404

A token standard designed to comply with corporate governance, banking standards, and securities law. ERC-1404 complies with ERC-20 and adds two new functions:

detectTransferRestriction and messageForTransferRestriction.

These functions allow issuers to enforce transfer restrictions within a smart contract, enabling them to control when ERC-1404 tokens can be transferred, how many can be transferred, and the conditions of a token transfer.

 

Ethereum Virtual Machine (EVM)

A Turing-complete virtual computer, run on every Ethereum node that allows anyone to execute arbitrary EVM Byte Code.

 

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

See: Hard Fork, Soft Fork.

 

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.

 

Fungibility

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

 

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. Equal to 1,000 Wei.

 

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.

 

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.

 

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.

 

Immutable

Unchanging over time or unable to be changed.

 

Initial Coin Offering (ICO)

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.

 

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.

 

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.

 

Maximum Supply

An approximation of the maximum number of coins or tokens that will ever exist for a cryptocurrency or crypto asset.

 

Mempool

The pool of pending transactions on a blockchain.

 

Merged Mining

The process of allowing two different cryptocurrencies based on the same algorithm to be mined simultaneously and on the same blockchain, as is the case with Bitcoin and Litecoin.

 

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.

 

Multi-signature Wallet

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

 

Network Effects

A phenomenon whereby increased numbers of users or participants improve the value of a good or service proportionally to the square of the number of its users (n2), known as Metcalfe’s law.

 

Network Externality

See Network Effect.

 

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.

 

Non-fungible Token (NFT)

A non-interchangeable type of cryptographic token which is unique.

 

Nothing-at-stake Problem

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

 

Open Source

Denoting software for which the original source code is made freely available and may be redistributed and modified.

 

Oracle

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

 

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.

 

Private Blockchain

A blockchain where write permissions are centralized to a single organization. Read permissions may be public, restricted or partially restricted.

 

Protocol

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

 

Privacy Coin (Privacy Token)

A cryptocurrency that provides its users with a high level of anonymity. Common privacy coins include Monero and Zcash.

 

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. Also referred to as Proof of Autonomy.

 

Proof of Autonomy

See Proof of Authority (PoA).

 

Proof of Stake (PoS)

An algorithm that rewards participants that solve cryptographic puzzles to achieve distributed consensus. Unlike proof of work, 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 proof of stake 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.

 

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).

 

Regulation A

Company must produce a report on the final status of the offering and provide an offering circular which has been filed with the SEC prior to the offering. The offering circular is subject to vetting by securities regulators on a state-by-state basis.

 

Regulation A+

Company must produce continuous reports on the offering (including its final status) and provide an offering circular which has been filed with the SEC prior to the offering. The offering circular is not subject to vetting by state securities regulators.

 

Regulation CF

As well as a maximum offer amount, investors are limited in the amount they may invest depending on annual income. The exchange must occur through a third party that is registered with the SEC and FINRA. Companies must also be eligible for the Reg. CF exemption.

 

Regulation D

Reg D allows smaller companies to raise capital through the sale of equity or debt securities without having to register their securities with the SEC. Securities sold are subject to a one-year lockup.

 

Regulation S

Regulation S is a “safe harbor" that defines when an offering of securities is deemed to be executed in another country and therefore not be subject to the registration requirement under section 5 of the 1933 Act. The regulation includes two safe harbor provisions: an issuer safe harbor and a resale safe harbor. In each case, the regulation demands that offers and sales of the securities be made outside the United States and that no offering participant engage in “directed selling efforts". The regulation also requires that no offers and sales be made to U.S. persons.

 

Ring Signature

A type of digital signature that can be used 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 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.

 

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.

 

Scalability

The ability of hardware or software to continue to function well when it is changed in size or volume in order to meet a user need. In the context of distributed ledger technology, scalability typically refers to a blockchain’s ability to maintain a high transaction throughput as the number of users increases.

 

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

A token that is compliant with federal securities regulations. A term commonly used to refer to tokenized securities.

 

Security Token Offering (STO)

An offering of security tokens, similar to an 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.

 

Sharding

In database architecture: A type of database partitioning that separates very large databases into more easily managed parts called data shards.

 

SHA-256

A cryptographic algorithm used by Bitcoin and other cryptocurrencies.

 

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.

 

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.

 

Solidity

The programming language for developing Ethereum smart contracts.

 

Stablecoin

A cryptocurrency designed to hold a stable value. Stablecoins are often collateralized by a fiat currency, a cryptocurrency, or a basket of cryptocurrencies.

 

State Channel

An interaction conducted off-chain without significantly increasing counterparty risk to any participant. State channels lock part of the blockchain state so that a specific set of participants must completely agree with each other in order to update it.

 

Stealth Address

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

 

ST-20

A token standard designed by PolyMath to comply with U.S. securities law. ST-20 complies with ERC-20 and adds a verifyTransfer method, which can override the transfer and transferFrom methods allowing for the creation of compliant, smart contract-enforceable transfer restrictions.

 

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.

 

Tangle

See Directed Acyclic Graph (DAG).

 

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. Made popular with the introduction of Ethereum.

 

Tokenized Security

A security token with value derived from an external financial asset.
Common standards include ERC-20, ST-20, ERC-1404.

 

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.

 

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 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 provides users with access (or future access) to a product or service.

 

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.

 

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 S, paper 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, protocol or blockchain.

 

Zero-knowledge Proof

A method by which one party can prove secret information without knowing the information itself. Most famously used by Zcash.

 

1 Percent Attack

An attack on a sharded proof-of-work system where an attacker can effectively achieve 100 percent control of a single shard by owning only one percent of the network’s hashing power.

 

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.

 

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.