Bearish
Bearish A term used to indicate negative sentiment towards the market or an asset, where investors believe that there will be downward price movement.

Bear Market
Contrary to bull market, it indicates the direction of the market going for downward trend.

Bitcoin
A digital currency created for use in peer-to-peer online transactions. Introduced in 2008 by a person or group using the name Satoshi Nakamoto, Bitcoin is the most prominent of a group of virtual currencies—money that exists mainly as computer code—that have no central issuing authority.

Bitcoin ATM
A machine from which you can buy or sell Bitcoin. Typically also offers different types of cryptocurrencies.

Bitcoin Evangelist
Individuals who are passionate about Bitcoin, and are dedicated in spreading knowledge about Bitcoin.

Bitcoin Improvement Proposal (BIP)
Refers to improvement proposals for Bitcoin, used to introduce features or any updates on the Bitcoin network.

BitLicense
Refers to the business license issued by the New York State Department of Financial Services (NYSDFS) to companies dealing with Cryptocurrencies (subject to certain exceptions) in New York.

Block
In the context of blockchain, block refers to the collection of transactional data or information that are bundled together in a predetermined size.

Blockchain
Describes its decentralized, public ledger which contains transactional information.

Block Confirmation
Refers to the number of confirmation a particular block has. Each block ahead of the referenced block adds one block confirmation to it.

Block Explorer
Application or websites which display information such as status of transactions or data contained in a block of a given public blockchain network.

Block Height
A number that is used to indicated the position of a particular block within a blockchain.

Block Reward
One of the mechanisms built into a blockchain to incentivize validators

Bots
Refers to software or programs that automatically trade based on preset behaviors.

Bounty
Public tasks available for anyone for a reward.

BUIDL
An advice for investors to contribute new projects on blockchain rather than holding cryptocurrencies and waiting for the price to increase.

Bullish
A term used to indicate positive sentiment towards the market or an asset, where investors believe that there will be upward price movement.

Bull Market
A bull market indicates the direction of the market going for upward trend.

Burned Tokens
Tokens which have been sent to addresses whose private key are not known, effectively becoming unusable.

Buy the Fucking Dip (BTFD)
An encouraging rally by cryptocurrency supporters to buy during a price decline.

Buy wall
Anomalously large buy order(s) at a single price point that reflects as a wall in the order book.

Byzantine Fault
A byzantine fault is where an error has occurred, yet a computer system does not know due which component/what failed to the lack of information and continues to iterate on a given instruction.

Byzantine Generals’ Problem
A term used to describe the situation a single strategy which requires consensus from all members within a group who cannot be trusted or verified.

Central Bank Digital Currency (CBDC)
Central Bank Digital Currency (CBDC)It is a digital fiat currency issued by the central banks, contrary to cryptocurrency that issued by non-legislative party.

Centralized
An organization structure wherein a small handful of actors have control over the entire network.

Central Ledger
The central data repository of a company or bank.

Circulating supply
An approximation of the number of coins or tokens that are currently not locked and available for public transactions.

Cloud Mining
Mining on blockchains through rented processing power rented from companies that host the physical equipment.

Cold Storage
Offline storage of cryptocurrencies which is arguably safer as they also require physical access (eg. hardware wallet, paper wallets).

Cold Wallet
Wallets that are offline and require physical access to certain devices (eg. hardware wallet, paper wallets).

Consensus
Consensus is achieved in a blockchain system when all participants agree on the content of the next block that will be added onto the blockchain.

Crypto Bubble
Like the internet bubble of 2003. It is a speculation in the cryptocurrencies and the price of cryptocurrencies would go extremely high before the bubble bursts.

Cryptocurrency
A form of digital currency that utilizes cryptographic protocols to record ownership and prevent counterfeiting.

Cryptography
A discipline or field of study which practices using cryptography to convert human-readable information that can only be deciphered by individuals who have the knowledge to.

Crypto Winter
Analogous to a bear market in conventional financial instruments, a crypto winter refers to a phase where the values of digital assets decline and persist at levels considerably below their recent peaks for an extended duration. 

Custody
Protective care or guardianship of an asset.

Daily Active Addresses (DAA)
On a blockchain, users interact with one another through their addresses, and daily active addresses (DAA) refers to the number of addresses which fulfills the defined activity parameter on a given blockchain.

Decentralized
A system where there are no centralized points of failure or organization with no central authority figure.

Decentralized applications (dApps)
Applications that run on decentralized peer-to-peer networks such as Ethereum.

Decentralized Autonomous Organization (DAO)
Open source and decentralized systems that do not require centralized operators or controllers.

Decentralized Finance (DeFi)
Refers to the movement of building decentralized financial applications that have no central authority and is censorship free.

Decryption
The process of decrypting data that was previously encrypted (made un-readable) back to a readable form.

Delegated Proof-of-Stake (dPOS)
A consensus mechanism where selected members of a network are voted as delegates to validate transactions and produce blocks on a blockchain.

Derivatives
A financial instrument which derives its value from the performance of an underlying asset or index (eg. gold, crude oil)

Derivatives Market
A market for derivatives which are instruments such as futures or options whose value is derived from an underlying asset.

Difficulty
A relative measure on how difficult it is to correctly guess a new block

Distributed Denial of Service (DDoS) Attack
A common cyber-attack tactic where a perpetrator diverts large amounts of traffic towards a particular network or service in an effort to disrupt normal services.

Distributed Ledger
Ledgers whose data is stored and synced across a network of nodes.

Distributed Ledger Technology (DLT)
The technology that enables distributed ledger.

Dominance
Typically refers to Bitcoin’s market capitalization dominance.

Double spending
Refers to the act of spending digital currencies twice. This is most commonly applied on crypto exchanges by unscrupulous actors.

Do Your Own Research (DYOR)
An advice for investors to do their own research on the coins they wanted to invest in.

Dump
A common term used to describe downward market movement, or to describe the action of selling an individuals holdings.

EIP (Ethereum Improvement Proposal)
Refers to improvement proposals for Ethereum, used to introduce features or any updates on the Ethereum network.

Emission
The speed/rate at which new coins are minted and released as dictated by the protocols written.

Encryption
In cryptography, encryption is a process of encoding information the original form of information called plaintext via an algorithm called cipher. The encrypted message is now called ciphertext. Only authorized parties can decipher the ciphertext and convert back it to the original plaintext.

Enterprise Ethereum Alliance (EEA)
Enterprise Ethereum Alliance is made up for a group of Ethereum developers, corporations as well as startups who are collaborating to find ways to use Ethereum for business applications.

ERC-20
ERC-20 is one of the most widely used token standards in Ethereum to create fungible, exchangeable tokens.

ERC-721
ERC-721 is one of the most widely used token standards in Ethereum to create non-fungible, exchangeable tokens.

Ethereum Virtual Machine (EVM)
An environment in which all smart contracts are executed.

Exchange Traded Fund (ETF)
An exchange-traded fund (ETF) is a form of security that tracks a collection of securities such as stocks, bonds, index or cryptocurrency but tradeable like a single stock.

Explain Like I Five (ELI5)
To explain in such simple terms that even a five-year-old would be able to understand it.

Faucet
A faucet usually represents a site or app where a user can navigate to for small rewards repeated over time.

Fear of Missing Out (FOMO)
Refers to the feeling of apprehension for missing out on a potentially profitable investment opportunity and regretting it later. Generally an expression describing investors fear of missing out the good timing of buying cryptocurrencies that could eventually be profitable.

Fear, uncertainty and doubt (FUD)
A strategy to dissuade people from buying a particular cryptocurrency by spreading false information.

Fiat-Pegged Cryptocurrency
Cryptocurrencies are pegged to an underlying asset usually the United States dollar.

Flappening
Flappening is a term used to describe Litecoin growing bigger and becoming more valuable than Bitcoin Cash (BCH). It is spawned from the term Flippening (used when another crypto overtakes Bitcoin).

Full node
Full Nodes are computers that verify the set of rules that are built into the protocols of a given cryptocurrency.

Futures
An agreement between two counterparties that obligates them to transact in the future based on the contract terms set.

Gas
A unit of measurement of the computational effort in conducting transactions or smart contracts on Ethereum blockchain.

Gas limit
A term refers to the maximum amount of units of gas a user is willing to spend on a transaction on Ethereum blockchain.

Gas price
A term refers to the amount of price user is willing to pay for a transaction on Ethereum blockchain.

Genesis block
It is the first block of data that is processed and validated to form a new blockchain, typically referred to as block 1.

Golden Cross
It is a bullish signal in technical candlestick pattern by comparing two lines of short-term moving average and long-term average. It is a golden cross when the short term moving average broke its long-term moving average.

Graphical Processing Unit (GPU)
They are chips dedicated to graphics processing or floating point operations, allowing to lighten the workload of the processors during applications usage such as video games.

Gwei
The monetary domination of gas, involving Ethereum.

Halving
An event that serves to reduce in half the reward of the Proof-of-Work miners that operate in the blockchain network.

Hard cap
The maximum amount that an ICO will be raising.

Hard fork
It is a permanent divergence of a blockchain into two blockchains. The original blockchain does not recognize the new version.

Hash
A hash function is an output code (unique and alphanumeric) that we obtain from an input string.

Hashrate
Total processing power of a blockchain or what is the same, are the amount of hash values that can be made in a period of time.

HODL
A crypto slang of saying holding the assets rather than selling it. A crypto slang encouraging investors to hold on to their assets rather than selling it. The very first time the term HODL appeared on the Bitcoin talk forum was in 2013 and came from a member amed GameKyuubi under the thread “I AM HODLING”. From the look of the post, he was intoxicated and wanted to say that he was holding his Bitcoin despite the serious decline in value that had just happened.

Hot Wallet
It is a tool that store your cryptocurrencies and always connected to internet.

Hybrid PoW/PoS
Is the allowance for both Proof-of-Work and Proof-of-Stake distribution consensus to work on the same network.

Hyperledger (Hyperledger Foundation)
Hyperledger is an open source collaborative effort to create blockchain technologies hosted by The Linux Foundation since 2016.

Initial Exchange Offering (IEO)
Is a spin-off of Initial Coin Offering (ICO), where the sale of tokens are conducted on an exchange rather than by the coin team themselves.

Immutable
A property characterized by inability to be change and stays unchanged over time.

Initial Coin Offering (ICO)
Is the equivalent of Initial Public Offering (IPO), where a company/cryptocurrency venture raises funds through crowd sales.

Internet of things (IoT)
It is a system that lets any devices that are connected to internet to communicate with each other without human-to-human or human-to-devices interactions.

Interoperability
Interoperability refers to the property of product or systems that are able to work with products or systems that are different, without any restrictions.

Initial Public Offering (IPO)
IPO refers to the process where a public company offers newly issued shares to the public and as a result raise capital from public investors.

Nothing to see here.  🙂

KYC (Know Your Costumer)
The know your customer or know your client (KYC) guidelines in financial services requires that professionals make an effort to verify the identity, suitability, and risks involved with maintaining a business relationship. The procedures fit within the broader scope of a bank’s Anti-Money Laundering (AML) policy. KYC processes are also employed by companies of all sizes for the purpose of ensuring their proposed customers, agents, consultants, or distributors are anti-bribery compliant, and are actually who they claim to be. Banks, insurers, export creditors and other financial institutions are increasingly demanding that customers provide detailed due diligence information. Initially, these regulations were imposed only on the financial institutions but now the non-financial industry, fintech, virtual assets dealers, and even the non-profit organizations are liable to oblige.

Ledger
A record of financial transactions that cannot be changed, only appended with new transactions. Also a popular cryptocurrency hardware wallet.

Leverage
It is an investment strategy to gain potential return of the investment by borrowing the money.

Lightning Network
It is a second layer or an off-chain of payment protocol that operates on top of a blockchain. Payments on this network do not need block confirmation and will be instant.

Limit Order / Limit Buy / Limit Sell
Orders placed by traders to buy or sell a cryptocurrency when a certain price is reached.

Liquidity
How easily a cryptocurrency can be bought and sold without impacting the overall market price.

Liquid Proof of Stake (LPoS)
A proof of stake consensus mechanism by Tezos that slightly differs from Delegated Proof of Stake.

Mainnet
It is the main network of Bitcoin, where the transactions of this cryptocurrency are registered and take place.

Margin Call
Margin call takes place when investor's margin account falls below the required amount to stay afloat.

Margin Trading
It is a way of investing by borrowing money from a broker (or in crypto, an exchange or platform) to trade.

Market capitalization (market cap)
In Crypto, market cap is measured by multiplication of the circulating supply of tokens or currency and its current price.

Market Maker
Participant of the market who creates buy and orders.

Market Order – Market Buy – Market Sell
A market order is a buy or sell order of stocks or cryptocurrency at the best price available in the current market as soon as possible.

Masternodes
Computers that are responsible for processing blockchain transactions and receive a reward when a block is mined.

Merkle Tree
A Merkle tree is also known as a hash tree in cryptography. It is a tree where every lead node is labelled with cryptographic hash of a data block, and every non-leaf node is labelled with the hash of the labels of its child nodes. It is used to verify of data stored within it and transferable in and between computers.

MicroBitcoin (uBTC)
One millionth of a bitcoin or 0.000001 of a bitcoin. Microbitcoin is the abbreviation of uBTC and often misunderstood as the fork of Bitcoin.

Microtransaction
Is a system that made very small payments possible in buying the common digital goods and services, such as purchasing items in a game.

Mineable
A cryptocurrency is said to be mineable when it has the system through which miners can be rewarded with newly-created cryptocurrencies for creating blocks.

Miners
Contributors to a blockchain taking part in the process of mining.

Mining
It is the process of the miners verify and adding transaction records into a block.

Mining Contract
Another term for cloud mining, where users can rent or invest in mining capacity online.

Mining Pool
Combination of resources of several miners to obtain a higher mining power and thus achieve greater rewards for the opening of blocks.

Mining Reward
The reward resulting from contributing computing resources to process transactions

Mining Rig
Dedicated often purpose built computer hardware used to mine cryptocurrency (blocks).

Mnemonic Phrase
A mnemonic phrase (also known as mnemonic seed, or seed phrase) is a list of words used in sequence to access or restore your cryptocurrency assets.

Mnemonics
Mnemonics are memory aids with a system such as letters or associations that help in recall. *see Mnemonic Phrase.

Money Printer Go Brrr
A meme made to describe the US Federal Reserve printing excessive amounts of money to support the traditional financial markets during the COVID-19 coronavirus pandemic.

Moon
Moon or To the moon is a crypto slang that describes an exclamation when the cryptocurrencies prices are rising and when it hit the peak, the coin is said to be mooning.

Mt. Gox
Mt. Gox was a bitcoin exchange based in Shibuya, Tokyo, Japan. Launched in July 2010, by 2013 and into 2014 it was handling over 70% of all bitcoin (BTC) transactions worldwide, as the largest bitcoin intermediary and the world’s leading bitcoin exchange.

In February 2014, Mt. Gox suspended trading, closed its website and exchange service, and filed for bankruptcy protection from creditors. In April 2014, the company began liquidation proceedings. Mt. Gox announced that approximately 850,000 bitcoins belonging to customers and the company were missing and likely stolen, an amount valued at more than $450 million at the time.[9][10] Although 200,000 bitcoins have since been “found”, the reasons for the disappearance—theft, fraud, mismanagement, or a combination of these—were initially unclear. New evidence presented in April 2015 by Tokyo security company WizSec led them to conclude that “most or all of the missing bitcoins were stolen straight out of the Mt. Gox hot cryptocurrency wallet over time, beginning in late 2011

Multisignal (multi-signature)
They are wallets that require more than one key for transactions to be authorized.

Node
Within the blockchain network, the nodes are computers that connect to the network and have an updated copy of the blockchain.
Node also refers to Any device connected to a network. For example, if the Presearch network connects 500 computers to it’s main database server,  there are 501 nodes on the network. Each device on the network has a network address, such as a MAC or IP address, which uniquely identifies each device.

Nonce
It means “number that is only used once” and it is of vital importance next to the hash in the verification of data from the Bitcoin blockchain network.

Non-custodial
It is a decentralized type-of-wallet, where the users owns its private keys.

Non-Fungible Tokens (NFT)
They are collectible elements within the Ethereum blockchain under ERC-721, where each token refers to a single element with a certain value.

Off-chain
It refers to transactions occurring outside the blockchain and executed instantly.

Offline Staking
Staking without needing to be connected to the blockchain

Open/Close
The price at which a cryptocurrency opens at a time period, for example at the start of the day; the price at which a cryptocurrency closes at a time period, for example at the end of the day.

Open Source
A type of software released under a license in which the copyright holder grants users the rights to study, change, and distribute the software to anyone and for any purpose.

Option
It is a financial instruments that refers to a contract offers the buyer the right to buy or sell an underlying assets at a specified price and time.

Oracles
In the crypto-world, oracles refers to services which verify real-world and provide data to blockchains/smart contracts.

Order Book
An electronic list of all buy and sell orders in an exchange.

Over The Counter (OTC)
Refers to the process that cryptocurrencies are being traded outside exchange and it is done directly between two parties.

Peer to peer

Peer to peer
A communication protocol that does not require a central hub.

Permissioned Blockchain
It is a private blockchain where the nodes must be previously authorized by a central entity.

Ponzi Scheme
A Ponzi scheme is also referred to as pyramid scheme, and typically takes the form of an investment scheme which pays existing investors with funds collected from new investors.

Portfolio
A portfolio consists all of your current crypto holdings in one place.

Pre-sale
A typically exclusive token sale event preceding a public ICO.

Privacy Coins
Cryptocurrencies that are designed with transaction anonymity and user privacy in mind.

Private Keys
The alphanumeric string which allows transactions from the cryptocurrency address.

Proof-of-Authority (PoA)
A consensus algorithm that assigns block validation queue based on identity and reputation.

Proof-of-Burn (PoB)
A consensus algorithm that assigns block validation queue based on the coins/token burned by the validator.

Proof-of-Developer (PoD)
A concept of identifying the developers of a project as a means of vouching reputation for a project.

Proof of Stake (PoS)
A consensus algorithm that assigns block validation queue based on the coins/token locked in by the validator.

Proof of Work (PoW)
A consensus algorithm in which a block is validated via mathematical hashing.

Protocol
The set of rules in a network in which participating members comply to allow proper communication.

Public Blockchain
An open sourced blockchain where participation is public and permission less.

Public Keys
The alphanumeric string which serves as a public receiving address in cryptocurrencies.

Pump and dump
A market manipulation method to drive up the price of an asset before profiting by driving it back down.

QR Code
Abbreviation for Quick Response Code, QR code is a machine readable optical label that stores up 3kb of data. Often used in cryptocurrency wallets to allow the public address to be copied.

REKT
A shorthand slang for “wrecked”, typically describes bad trades that results in losses.

Relative Strength Index (RSI)
Relative Strength Index (RSI) is a popular technical indicator used to analyze financial markets. By charting the current and historical closing prices to evaluate overbought/oversold conditions, RSI oscillates between 0 – 100, with 30% indicating oversold and 70% indicating overbought.

Ring Signature
A type of digital signature performed in a group where it becomes impossible to determine which member's key in the group were used for the digital signature.

ROI
Short for “Return on Investment”, the ratio between the net profit and cost of investing.

Salt (cryptography)
In cryptography, a salt is the additional random input that is added to password or passphrase to make the password hash unique. It prevents from the hashed output password to be cracked so easily by the hacker.

Satoshi
A unit measure for the smallest divisible unit of a bitcoin. 1 bitcoin is equal to 100 Million Satoshi.

Satoshi Nakamoto
The pseudonym used in publishing the Bitcoin Whitepaper. Identity of this person or group of people is unknown.

Scrypt
one of the hashing algorithm used in proof-of-work protocol, scripts requires more memory in order to performing mining functions.

Second-Layer Solutions
Secondary network or framework built atop an existing blockchain to address transaction speed and scalability issues.

Secure Asset Fund for Users (SAFU)
A feature created by Binance which contains reserve funds that can be used to reimburse users in case of a catastrophic event (eg. exchange hack)

Securities and Exchange Commission (SEC)
U.S. Securities and Exchange Commission, an independent agency of the US Federal government which oversees federal securities laws, proposing securities rules, and regulating the securities industry.

Seed
A value used to initiate generation of pseudorandom number, usually a string of 12 common English words.

Segregated Witness (SegWit)
A soft fork implementation to change the Bitcoin Protocol’s transaction format to address Bitcoin’s scalability issues whilst introducing new features.

Sell wall
Anomalously large sell order(s) at a single price point that reflects as a wall in the order book.

SHA-256
Abbreviation of Secure Hashing Algorithm – 256 SHA-256 is part of the SHA2 that allows one-way hashing of any data into a 64 character string.

Sharding
A form of database partitioning which breaks up data into smaller segments.

Shilling
One who poses as a enthusiastic customer or supporter of a token, coin or project as a form of covert advertising.

Shitcoin
A coin with no obvious potential value or usage.

Side Chain
A separate blockchain ledger that runs parallel with the primary blockchain.

Sim Swapping
It is a tactic where hacker overtake the mobile phone to exploit the two-factor authentication and two-step verification.

Smart Contracts
Self executing contracts on the blockchain without needing human intervention.

Soft Cap
Targeted fund raising limit of an ICO.

Soft Fork
A backward-compatible update to a decentralized blockchain protocol.

Software Development Kit (SDK)
It is a collection of software development tools in one package installation. It is designed to help developing applications for a specific device or operating system (OS).

Solidity
Object oriented programming language used in various smart contract blockchains.

Stablecoin
Cryptocurrency with a price peg to fiat currencies or commodity.

Staking
The state of locking-in significant amount of token to participate as a validator of a Proof-of-Stake network.

Stale Block
Double mined blocks that are not included in the blockchain.

State Channel
Secondary payment channel occurring off-chain.

STO
Security Token Offering (STO) refers to a public offering for tokenized digital securities, or in short security tokens traded in cryptocurrency exchanges.

Stop-loss Order
Conditional market order to sell at the next available price, excecuted if the price of an asset falls below set-upon limit.

Testnet
Shorthand for Test Network, testnets are staging areas for experimenting new blockchain features.

Ticker
A ticker is a stock or asset symbol that abbreviates the asset name and it can be used as an identifier of the asset.

Token
Blockchain based unit of value issued by an organization, which grants token holders a right to participate in a network.<

Token Burn
An event in which tokens are verifiably removed permanently removed from circulation.

Token Generation Event (TGE)
An event in which new tokens (usually on a smart contract platform) are created and distributed to the public.

Total supply
All the tokens and coins that will exist in a cryptocurrency network.

Trading Volume
The amount of the cryptocurrency that has been traded in the last 24 hours.

Transaction Fee
A payment to the network for performing a transaction to be recorded on the blockchain.

Transactions per second (TPS)
It is number of transactions done per second. For example, there are 10 transactions completed in 1-minute. The TPS would be 10 transactions/60 seconds = ~0.17 TPS.

Trustless
Entirely verifiable, without needing to trust or assume an action is done completely and in good faith.

Unspent Transaction Output(UXTO)
Coins that are unspent in the wallet. Uxto virtually represents the cryptocurrency one own in the wallet.

UTC Time
Universal Time Coordinated can be used interchangeably with Greenwich Mean Time (GMT).

Utility Token
A cryptocurrency tokens with specific utilities on a network besides being used as medium of exchange and investment vehicle.

Validator
A block-signing participant of a Proof of Stake blockchain network, whom have significant tokens staked on the network.

Wallet
Software client that handles storage of cryptocurrencies and allows users to send cryptocurrencies.

Wallet Address
The address in which cryptocurrency can be stored, sent to and receive.

Wash Trade
Meaningless back and forth trading between a single party with the aim of inflating trade volume.

Watchlist
A personally defined list of values to watch over for activity or changes.

Web3 Wallet
Web3 Wallet is the software that allows you to interact with web 3.0.

Wei
The smallest fraction of an Ether, with each Ether to 1000000000000000000 Wei.

Whale
Someone who holds an enormous amount of cryptocurrency and has the ability to wave the market.

When Lambo?
An expression used by investors to ask when the value of their investment could buy them a Lamborghini.

When Moon?
An expression used by investors to ask when the price of a coin would hit a peak.

Whitelist
List of approved participants that will be given access to a token sale (ICO, IEO, STO etc…).

Whitepaper
An introductory paper to concisely explain an issue and a possible solution on the issue.

Nothing to see here.  🙂

YTD
Acronym for Year-to-date.

Zero Confirmation Transaction
Another name for an unconfirmed transaction.

Zero Knowledge Proof
Cryptographic proof for 2 parties to verify a value without revealing what the value is.

Zero-Knowledge Succinct Non-Interactive Argument of Knowledge (Zk-Snarks)
An acronym for Zero-Knowledge Succinct Non-Interactive Argument of Knowledge, zk-SNARKs refers to a protocol where one can prove possession of a given piece of information (eg a string or hash) without revealing that information and also without any interaction between both the prover and verifier.