The Semi-Comprehensive & Ever-Growing List of Crypto Terminology
51% ATTACK: A 51% attack is a situation where more than half of the computing power on a network is operated by a single individual or concentrated group, which gives them complete and total control over a network. Things that an entity with 51% of the computing power can do include, but are not limited to: Halting all mining, halting and manipulating all interpersonal transactions and to use singular coins over and over.
ADDRESS: A bitcoin address is essentially the same thing as your home address. It’s the location from which you would receive, send or hold your currency. These addresses generally manifest in a long string of alphanumeric characters
AGREEMENT LEDGER: An agreement ledger is distributed ledger used by two or more parties to negotiate and reach agreement.
ALPHABET: The alphabet is the set of characters which will be affected by the encryption process. This is usually the set of 26 letters, but could also be enlarged to contain punctuation and numbers to make a cipher more secure.
ALTCOIN: A cryptocurrency or a category of cryptocurrencies that are an alternative to bitcoin. Many altcoins project themselves as better alternatives to bitcoin in various ways (e.g. more efficient, less expensive, etc.).
AML: Acronym for ‘Anti-Money Laundering’, used to describe a series of laws and regulations which require financial institutions to know the identity of their customers and prevent malicious activities, as well as verify the origin of the funds used.
ASIC: Application Specific Integrated Circuit is a chip specifically created to execute one task. GPU or CPU can be considered ASIC. ASIC term grew in popularity with bitcoin mining.
ASIC/ASIC MINER: ASIC mining is a crafty method of mining various coins at a much faster rate than any normal desktop or laptop might allow.
ASYMMETRIC KEY ALGORITHM: This is the algorithm used to generate public and private keys, the unique codes that are essential to cryptocurrency transactions. Both parties have access to the public key, but only the person with the private key can decode the encryption; this assures that only they can receive the funds.
ATTESTATION LEDGER: A distributed ledger providing a durable record of agreements, commitments or statements, providing evidence (attestation) that these agreements, commitments or statements were made.
BEAR TRAP: This is a manipulation of a stock or commodity by investors. Traders who “set” the bear trap do so by selling stock until it fools other investors into thinking its upward trend in value has stopped, or is dropping. Those who fall into the bear trap will often sell at that time, fearing a further drop in value. At that point, the investors who set the trap will buy at the low price and will release the trap—which is essentially a false bear market. Once the bear trap is released, the value will even out, or even climb.
BITCOIN: A digital, or crypto, currency that enables payment in a decentralized peer-to-peer (P2P) network not governed by any central authority or middleman.
BITCOIN CASH: An alt-coin clone of bitcoin that was created in August 2017 when a group of Chinese miners initiated a hard fork of bitcoin’s blockchain.
BITCOIN PRICE INDEX (BPI): Gathers information from the largest and most influential Bitcoin exchanges in the world, and applies the aggregated statistics to reach a more balanced and realistic picture of the currency’s market value. The BPI has a set of criteria—best practices guidelines for the exchange industry, if you will—and exchanges that don’t meet or accept these criteria aren’t included in the BPI statistics.
BLOCK: Blocks are essentially pages in a ledger or record keeping book. Blocks are the files where unalterable data related to the network is permanently stored.
BLOCK EXPLORER: Online tool to view all transactions, past and current, on the blockchain. They provide useful information such as network hash rate and transaction growth. BLOCK HEIGHT: Block height is the number of blocks preceding the genesis block (first block) on the chain. A genesis block will always have a height of zero because nothing precedes it. It’s a metric used to create a bearing on time in the programming world as well as a few other functions such as maintaining counter-party and betting in the crypto world.
BLOCK REWARD: Block reward is the reward allotted for hashing, or solving the mathematical equation related to a block. The reward for mining a Bitcoin block is 25 bitcoins per block mined, which will halve every 210,000 blocks.
BLOCKCHAIN: Software that first emerged as the system underpinning bitcoin. Also known as distributed ledger technology (DLT), it is a shared record of information that is maintained and updated by a network of computers rather than a central authority. It is protected and secured by advanced cryptography.
BOT TRADING: The majority of investors in digital currency use manual methods when they want to buy or sell their cryptocurrency of choice. However, there are now programs available for investors that have been created to make the process more precise and automatic. They download these programs, which monitor alternative currency exchanges and markets for them. These “bots” will carry out transactions automatically according to the price criteria the investor has set.
BREAK: To break a code is to work out what the original message of an intercepted text is. This is done using a variety of ways and a large amount of human input is required.
BUBBLE: A bubble occurs when a market is driven upward by investors; this has happened in the dot-com and housing industries in the past decade or so. Factors such as industry popularity, speculation of potential worth, political influence, and many other things can combine to create these spikes in value. If the market is perceived to have “topped out,” or investors believe it will no longer retain its overall worth, the bubble can “burst.” This represents a massive sell-off by investors, which can make market value drop sharply.
BULL TRAP: A bull trap is “set” by investors in a stock or commodity who will buy large amounts in order to artificially drive the value upward, or create a false bull market. Traders who are fooled by the bull trap will often buy shares at the inflated price, in the belief that the upward trend will continue and the shares they’re buying will rise in value.
BUY ORDER: A buy order is established when an investor approaches an exchange and wants to purchase cryptocurrency.
CENTRAL LEDGER: A ledger maintained by a central agency.
CIRCULATING SUPPLY: An approximation of the number of coins or tokens that are circulating in the public market. See also: total supply and maximum supply.
COLD STORAGE: The term cold storage is a general term for different ways of securing your bitcoins offline (disconnected from the internet). This would be the opposite of a hot wallet or hosted wallet, which is connected to the web for day-to-day transactions. The purpose of using cold storage is to minimize the chances of your bitcoins being stolen from a malicious hacker and is commonly used for larger sums of bitcoins.
COLLECTIVE MINING: The commitment of resources and materials to the process of mining digital currency data blocks often proves to be too expensive for individuals to take part.
CONFIRMATION: The successful act of hashing a transaction and adding it to the blockchain.
CONSENSUS: Consensus is achieved when all participants of the network agree on the validity of the transactions, ensuring that the ledgers are exact copies of each other.
CRYPTOCURRENCY: A digital currency that relies on cryptography to validate and secure transactions. There are different types of cryptocurrencies. Bitcoin and ethereum are among the best known.
CRYPTOGRAPHIC HASH FUNCTION: Cryptographic hashes produce a fixed-size and unique hash value from variable-size transaction input. The SHA-256 computational algorithm is an example of a cryptographic hash.
CRYPTOGRAPHY: Essentially mathematical and computer science algorithms used to encrypt and decrypt information, is used in bitcoin addresses, hash functions, and the block chain.
DAO: Decentralized Autonomous Organizations can be thought of as corporations that run without any human intervention and surrender all forms of control to an incorruptible set of business rules.
DAPP: Decentralised application (Dapp) is an application that is open source, operates autonomously, has its data stored on a blockchain, incentivised in the form of cryptographic tokens and operates on a protocol that shows proof of value.
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.
DEFI: Decentralized Finance. A broad-based term for cryptocurrencies that are focusing on replicating or replacing the aspects of the current financial system. Examples could be decentralized exchanges (DEX's), lending, insurance, or yield farming.
DEX: A Decentralized Exchange where individuals provide token pairs to liquidity pools. Traders can then purchase or sell tokens through these liquidity pools at market price without having to go through a traditional exchange.
DIFFICULTY: This refers to how easily a data block of transaction information can be mined successfully.
DIGITAL SIGNATURE: A digital code generated by public key encryption that is attached to an electronically transmitted document to verify its contents and the sender’s identity.
DIGITAL WALLET: Software that allows users to make electronic payments, purchases and store their cryptocurrencies online.
DISTRIBUTED APPLICATION: Software that runs on multiple computers on a given network at the same time.
DISTRIBUTED CONSENSUS: Collective agreement by various computers in a network and allows it to work in a decentralized, P2P manner without the need of central authority to deter dishonest network participants.
DISTRIBUTED LEDGER TECHNOLOGY: A term often used interchangeably with “blockchain,” although technically blockchain describes the public ledger powering bitcoin.
DOGECOIN: A cryptocurrency featuring a Shiba Inu dog from the famous “Doge” internet meme. Launched as a joke, this is one of the top altcoins.
DOUBLE SPEND: A successful bitcoin transaction that is sent to two different recipients simultaneously. It’s essentially as if the same dollar bill could be spent twice. Bitcoin’s blockchain is the system that should prevent this from happening.
ERC-20: A type of 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 ICOsare compliant with the ERC-20 standard.
ETHER (ETH): A type of cryptocurrency that is 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.
ETHEREUM: A type of blockchain network. The bitcoin and Ethereum blockchains differ primarily in purpose and capability. While the bitcoin blockchain is used to track ownership of the digital currency bitcoin, the Ethereum blockchain can be used to build decentralized applications.
ETH 2.0: A series of anticipated upgrades and updates to the existing Ethereum network.
ETHEREUM CLASSIC (ETC): A type of cryptocurrency that is a continuation of the original Ethereum blockchain following the DAO attack in June 2016. Ethereum is essentially a hard fork of the blockchain that was formed to refund the money that was syphoned during the attack (around $50 million). Ethereum Classic assumes no hard fork occurred and is supported by those who believe in the complete immutability of the blockchain.
EVM: The Ethereum Virtual Machine (EVM) is a Turing complete virtual machine that allows anyone to execute arbitrary EVM Byte Code. Every Ethereum node runs on the EVM to maintain consensus across the blockchain.
FIAT MONEY: 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 and coins. For example, USD can be considered a fiat currency and there aren’t any real currencies with their value measured in gold.
FLIPPING: A type of investment strategy (popular in real estate investing) where you buy something with the goal of reselling for a profit later, usually in a short period of time. In the context of ICOs, flipping refers to the strategy of investing in tokens before they are listed on the exchanges and reselling them for a profit when they are trading in the secondary market.
FOMO: An acronym that stands for ‘fear of missing out’ and in the context of investing, refers to the feeling of apprehension for missing out on a potentially profitable investment opportunity and regretting it later.
FRAUD PROOF: A set of data, usually a part of a block plus some extra ‘witness data’ (eg. Merkle branches), that can be used to prove that a given block is invalid.
FULL NODE: A full node is when you download the entire block chain using a bitcoin client, and you relay, validate, and secure the data within the block chain. The data is bitcoin transactions and blocks, which is validated across the entire network of users.
FORK: The permanent divergence of an alternative operating version of the current blockchain. Forks come into existence when a 51% attack occurs, a bug in the program, or more commonly a new set of consensus rules come into existence. These happen when a development team creates and inserts notably substantial changes into the system. The successful fork is decided by the height of their blocks.
FUD: An acronym that stands for fear, uncertainty and doubt. It is a strategy to influence perception by spreading negative, misleading or false information about something, as opposed to reasoned criticism.
GAS: Measurement roughly equivalent to computational steps (for Ethereum). Every transaction is required to include a gas limit and a fee that it is willing to pay per gas; miners have the choice of including the transaction and collecting the fee or not. Every operation has a gas expenditure; for most operations it is ~3–10, although some expensive operations have expenditures up to 700 and a transaction itself has an expenditure of 21000.
GAS LIMIT: A term used in the Ethereum platform that refers to the maximum amount of units of gas 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 will make miners more incentivized to prioritize and validate that particular transaction ahead of those set with a lower gas price. Gas prices are typically denominated in Gwei. For more information on the various ether denominations, see this documentation.
GENESIS BLOCK: The first block in a new blockchain.
GIGAHASHES/SEC: The amount of hashes possible every second, measured in billions of hashes
GPU: Acronym for “graphics processing unit” is a specialised processor originally designed for the high graphics requirements of computer games. These are also used to mine cryptocurrency since they outperform CPUs.
HALVING: Reduction of minable reward every so many blocks. For Bitcoin the reward is halved after the first 210,000 blocks are mined and then every 210,000 thereafter.
HARD FORK: When a blockchain splits into two ledgers creating a new digital currency.
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.
HARDWARE SECURITY MODULES: Or HSM. It is a device that secures data such as digital private keys in a very secure fashion.
HASH: The act of performing a hash function on the output data. This is used for confirming coin transactions.
HASH RATE: Measurement of performance for the mining rig is expressed in hashes per second
HODL: A type of passive investment strategy where you hold an investment for a long period of time, regardless of market volatility. The term was made famous by a typo made in a bitcoin forum. Also referred to as ‘buy and hold’ or ‘hold on for dear life’.
HYBRID PoS/PoW: Allows for both Proof of Stake and Proof of Work as consensus distribution algorithms on the network. In this method, a balance between miners and voters (holders) may be achieved, creating a system of community-based governance by both insiders (holders) and outsiders (miners).
ICO: Initial Coin Offering, or a token sale. This is the process or event in which funds are raised for a new cryptocurrency venture and contributors receive tokens in return.
INPUT: The input side of a given Bitcoin transaction is the side where the Bitcoin payment is coming from. Usually, this is expressed with a Bitcoin address.
IOTA (MIOTA): 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, fast and secure transactions, and so on. It is focused on the Internet of Things.
KIMOTO GRAVITY WELL: A mining difficulty readjustment algorithm, which was created in 2013 for Megacoin, an altcoin. The well allows difficulty readjustment to occur every block, instead of every 2016 blocks for Bitcoin. This was done as a response to concern about multi pool mining schemes.
KYC: Acronym for ‘Know Your Customer’, used to describe a series of laws and regulations which require businesses to know the identity of their customers.
LAYER 2 SOLUTION: Usually in conjunction with smart contracts build on Ethereum, Layer 2 Solutions is an umbrella term for applications that increase speed and/or decrease GAS fees on Ethereum. Examples include ZK (Zero Knowledge) Rollups, Optimistic Rollups, and side chains.
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 the whitepaper.
LIQUIDITY POOL: A pool of funds in a smart contract that provide funding for Decentralized Exchanges. A liquidity provider puts up equal amounts of two tokens to create a trading pair. Traders can the buy or sell the tokens in the pair without having to go through a centralized exchange.
LITECOIN (LTC): A type of 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.
MARKET CAPITALIZATION (MARKET CAP): The market value of a company, market or sector at a point in time commonly used to rank relative size. In equities, it refers to the total market value of a company’s outstanding shares. In cryptocurrency investing, it refers to either price multiplied by the circulating supply (i.e. free float market cap) or price multiplied by the total supply (i.e. fully diluted market cap).
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.
MINERS: Term used to describe the devices or the people that own the devices that validate bitcoin transactions. They get rewarded for the computing power consumed during mining with the bitcoins created in the process.
MINING: The process through which transactions are verified and added to the blockchain and new bitcoins are created.MONERO: A type of cryptocurrency created in 2014 that is focused on privacy and scalability, and runs on platforms like Windows, Mac, Linux and Android. Transactions on Monero are designed to be untraceable to any particular user or real world identity.
MULTISIG: Or multisignature refers to having more than one signature to approve a transaction. This form of security is beneficial for a company receiving money into their BTC wallet. If a company wants to keep it so that one employee doesn’t have sole access to a transaction, multisig allows for a transaction to be verified by two separate employees before it’s complete.
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.
NFT: Non-fungible Token. A completely unique item that cannot be exchanged or traded for another like item. Examples could be digital art, gaming skins, music, digital collector cards, etc.
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.
NODES: Connection points for the transmission of data.
OFF-LEDGER CURRENCY: A currency minted off-ledger and used on-ledger. An example of this would be using distributed ledgers to manage a national currency.
ON-LEDGER CURRENCY: A currency minted on-ledger and used on-ledger. An example of this would be the cryptocurrency, Bitcoin.
ORACLES: A data feed, usually a third party service, that provides information for use in smart contracts.
P2P: Another way of saying Peer-to-Peer. Peer-to-peer has become a very large focus of blockchain as one of the biggest selling points is decentralization. Nearly every interaction on the blockchain can be fulfilled P2P, or without a centralized variable like a store, bank or notary.
PERMISSIONED LEDGER: A distributed ledger that requires permission in order to be accessed. The ledger is maintained only by a limited number of parties. This is the kind of blockchain technology that large corporations, such as banks, are more likely to use because of data privacy needs.
POS: Proof of stake has been considered the greener alternative to PoW. Where PoW requires the prover to perform a certain amount of computational work, a proof of stake system requires the prover to show ownership of a certain amount of money, or stake.
POW: Proof of work was a concept originally designed to sieve spam emails and prevent DDOS attacks. A Proof of Work is essentially a datum that is very costly to produce in terms of time and resources, but can be very simply verified by another party. The proof of work for Bitcoin is referred to as a “nonce,” or number used only once.
PRE-SALE: A sale that takes place before an ICO is made available to the general public to participate.
PRIVATE KEYS: A form of cryptography that allows users to access their cryptocurrency and is an essential part of its security.
PUBLIC ADDRESS: A public address is the cryptographic hash of a public key. They act as email addresses that can be published anywhere, unlike private keys.
PUBLIC LEDGER: A distributed ledger that is open to everyone on the internet. Bitcoin’s blockchain is a public ledger.
PUMP AND DUMP SCHEME: A scheme in which the development team (or short-term traders) hypes up a project without fundamental basis in order to pump up the price of the tokens temporarily and then sells their holdings immediately after launch to earn a profit.
QR CODE: These are a lot like the rectangular barcodes you’ll find on just about anything you buy, except QR codes are square in shape and can hold more information than bar codes.
RIPPLE (XRP): Refers to the cryptocurrency and the name of an open source payment platform where the cryptocurrency (Ripple or 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.
SATOSHI: The smallest unit of bitcoin possible. There are 100 million satoshis in a single bitcoin.
SATOSHI NAKAMOTO: The mysterious creator of Bitcoin. Known to possess over a million bitcoins, his/her/their/its identity is still unknown.
SCAMCOIN: Coins created as get rich quick schemes by their developers. These coins usually have certain properties, such as being clones of an existing coin and being pre-mined.
SCRYPT: Type of cryptographic algorithm and is used by Litecoin. Compared to SHA256, this is quicker as it does not use up as much processing time.
SEGEREGATED 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 essentially split (or ‘segregated’), into two segments: the original data segment and the signature (or ‘witness’) segment.
SHA-256: Cryptographic algorithm used by cryptocurrencies such as Bitcoin. However, it uses a lot of computing power and processing time, forcing miners to form mining pools to capture gains.
SIGNATURE: Mathematical operation that lets someone prove their sole ownership over their wallet, coin, data or on. An example is how a Bitcoin wallet may have a public address, but only a private key can verify with the whole network that a signature matches and a transaction is valid. These are only known to the owner and are basically mathematically impossible to uncover.
SMART CONTRACTS: Software that runs on blockchain technology and can automatically enforce the terms of an agreement. A “smart bond,” for example, would automatically make interest payments to investors
SOFT CAP: Generally refers to the minimum amount that an initial coin offering (ICO) needs to raise. If the ICO is unable to raise that amount, it may be cancelled and the collected funds returned to participants.
SOFT FORK: It differs from a hard fork in that only previously valid transactions are made invalid. Since old nodes recognize the new blocks as valid, a soft fork is essentially backward-compatible. This type of fork requires most miners upgrading in order to enforce, while a hard fork requires all nodes to agree on the new version.
SOLIDITY: Ethereum’s programming language for developing smart contracts.
TESTNET: A test blockchain used by developers to prevent expending assets on the main chain.
TOTAL VALUE LOCKED: Total Value Locked (TVL) represents the dollar-value sum of all assets deposited in decentralized finance (see: DeFi) protocols that actively earn interest, rewards, or any other form of passive income.
TOKEN: Crypto tokens enable the creation of open, decentralized networks, and provides a way to incentivize participants in the network (with both network growth and token appreciation). This innovation, made popular with the introduction of Ethereum, has given rise to a wave of token networks (e.g. prediction markets, content creation networks, etc.) and token pre-sales, or ICOs.
TRANSACTION BLOCK: A collection of transactions gathered into a block that can then be hashed and added to the blockchain.
TRANSACTION FEE: All cryptocurrency transactions involve a small transaction fee. These transaction fees add up to account for the block reward that a miner receives when he successfully processes a block.
TURING COMPLETE: Turing complete refers to the ability of a machine to perform calculations that any other programmable computer is capable of. An example of this is the Ethereum Virtual Machine (EVM).
UNPERMISSIONED LEDGERS: Unpermissioned ledgers such as Bitcoin have no single owner — indeed, they cannot be owned. The purpose of an unpermissioned ledger is to allow anyone to contribute data to the ledger and for everyone in possession of the ledger to have identical copies.
VANITY ADDRESS: A bitcoin address which contains a desired word/pattern or sequence of numbers. Kind of like a customised number plate. (Example: 1JAMES2K4rWaduCmCds36ox2VXdeBE7LNd)
VIRGIN BITCOIN: A bitcoin that has been received by a miner as a block reward, and thus has never been “spent” before.
VOLATILITY: The measurement of price movements over time for a traded financial asset.”
WALLET: A store of digital assets such as cryptocurrencies, analogous to a digital bank account. Crypto wallets can be divided into two categories: hosted 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).
WALLET ADDRESS: Public portion of the two encrypted keys necessary for a holder to accept or verify a transaction.
WHALE: Someone who possesses a Majority percentage of a cryptocurrency.
WHITELIST: A list of registered and approved participants that are given exclusive access to contribute to an ICO or a pre-sale.
WHITEPAPER: An informational document that generally informs readers on the philosophy, objectives and technology of a project or initiative. Whitepapers are often provided before the launch of a new coin or token.
WYCKOFF METHOD: Theory of trading developed by Richard Wyckoff. This theory involves the idea that traders can search for the "Comp Man," the sum of all trading knowledge and activity that expresses itself through a series of known patterns.
ZEROCOIN: A project aimed at implementing true anonymity into the Bitcoin network.
ZERO CONFIRMATION TRANSACTION: The processing of data for cryptocurrency transactions can take anywhere from half a minute upward to over ten minutes in some cases. Though this is necessary in order to validate transactions and guards against fraudulent activity such as double spending – the waiting period can be inconvenient for those involved in the transactions. As a result, some exchanges and businesses that deal with digital currency are offering “zero confirmation” transactions, which are almost immediately verified without waiting for the mining process to confirm the data block.
Sources: Investopedia, Reuters, Bloomberg, Blockgeeks, Blockchaintechonologies.com, Cryptocorner, Barcodesinc, stockcharts.com.