A procedure that is meant to provide increased security of sensitive information in an age of increasing cybercrime. The security protocol calls for both a password and an additional piece of information, often something that is in the physical possession of the user such as a smartphone or credit card.
An accidental fork happens when two or more miners find a block almost simultaneously. One chain then becomes longer than the other, and the network eventually abandons the blocks that are not in the longer chain. These blocks are then classified as ‘orphaned blocks.’
A distributed ledger providing a durable record of agreements, commitments, or statements, providing evidence (attestation) that these agreements, commitments, or statements were made.
An online tool for exploring the blockchain of a particular cryptocurrency, where you can watch and follow all the transactions happening on the blockchain. Block explorers can serve as blockchain analysis and provide information such as total network hash rate, coin supply, transaction growth, etc.
A pseudorandom number computed by hashing together the BlockSeed of the previous block and the Account Address of the new Blocksmith.
Used as a seed for any deterministic random numbers that must be used for this block, such as calculating the SmithTime for all Blocksmiths, computing the PoP Group for this block, and computing the PoP Rewards list.
The ability of a network to properly reach consensus at any time, assuming that no more than 2/3 of its actors are malicious. Checkpointing is commonly used alongside to make data stored on the blockchain final.
Classical cryptocurrency mining requires huge investments in hardware and electricity. Cloud mining companies aim to make mining accessible to everybody. People just can log in to a website and invest money in the company which already has mining datacenters.
The “sender” of a special transaction included in every new block (on some blockchains) that creates new tokens from nothing. These tokens are given as a reward to the miner that creates the new block, thereby increasing the total amount of tokens in circulation within the blockchain. Some blockchains use the coinbase only at block 0 and have 100% of their tokens already created when the blockchain is launched. (“Coinbase” should not to be confused with the cryptocurrency exchange from San Francisco of the same name.)
The blockchain element that determines how consensus is reached on that blockchain. In other words; it is the part of the blockchain protocol that describes who gets to validate blocks of data (and thus is entitled to the reward) and how others can verify its legitimacy.
A blockchain where a pre-selected set of nodes handles the consensus process. It is also called a permissioned blockchain network that can be a hybrid model built between the trusted entity model of private blockchains and low trust provided by the public blockchain.
A function that returns a unique big number that is commonly represented as fixed-length string. The returned string is unique for every unique input. Used to create a “digital ID” or “digital thumbprint” of an input data(bits).
The encryption and decryption of data. There are two main cryptographic concepts used in the blockchain – Hashing and Digital Signatures. In general, there are three forms of encryption that are widely used – symmetric cryptography, asymmetric cryptography, and hashing.
An unauthorized use of a device owned by others, to mine cryptocurrency. The first widely known attempt for cryptojacking was the torrent tracker Piratebay. They enabled an in-browser mining software, so when somebody visits the website, his/her computer will start mining cryptocurrency via the browser with no indication of it happening.
A method for decentralized funding of projects. It combines ideas from Decentralized Autonomous Organizations (DAOs) and Initial Coin Offerings (ICOs). Project investors have the ability to vote and, if dissatisfied with the progress of the project, could get their money back.
A denial-of-service attack is a cyber-attack in which the perpetrator seeks to make a machine or network resource unavailable to its intended users by temporarily or indefinitely disrupting services of a host connected to the Internet.
Refer to the first step in the Blockchain 3 layer model. They are a set of concepts or properties that you wish your smart contract to have. These include Distribution, Decentralization, Immutability, and Peer-to-Peer.
Anything used by friends or institutions to identify you online, such as email address/Twitter handle, etc. On the blockchain, when you sign something (with the private key), you are also proving your identity.
A type of computer database that is stored on many private computers at the same time, instead of central company servers. A distributed ledger does not have to have its own currency and may be permissioned and private. Blockchains are also known as distributed ledgers.
A token standard with a focus on security that allows token transfers to act as ETH transactions, using event handling (transaction management) to prevent lost tokens. This standard is an improvement on the ERC20 critical bug.
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.
A variable number to which set fees needs to be multiplied by, to give an adjusted fee amount to be paid for transactions. Operators of registered nodes on the network may take a regular vote on the appropriate multiplier, which we call the fee scale, for minimum transaction fees. This guarantees that while the value of the blockchain token may fluctuate, the fees to be paid for transaction remain stable against regular currency.
Fungible means that a given good is identical (a.k.a., interchangeable). In crypto, we often talk about fungible or non-fungible tokens. A fungible token is Bitcoin. One Bitcoin is and will always be one Bitcoin, just like any other Bitcoin.
The world’s first fast, secure and fair distributed ledger, Hedera Hashgraph can perform 500,000 transactions per second. It is a directed acyclic graph that has the properties of the DLT and doesn’t need Proof-Of-Work like blockchain-based platforms.
Transforms the input data into a hash value that is sent to the receiver as a digital fingerprint. The receiver uses the same hash function to generate the hash value and then compares it to that received with the message. If the hash values are the same, it is likely that the message was transmitted/stored without errors.
Linux foundations hosted the blockchain project known as Hyperledger. An open-source platform, Hyperledger aims to bring collaborative effort from the blockchain experts in the market for the enhancement of Blockchain technology. It comprises various systems and tools for developing open-source blockchains.
Distribution protocol that started as an open source project at Interplanetary Networks. The p2p method of storing and sharing hypermedia in a distributed file system aims to help applications run faster, safer, and more transparently. IPFS allows objects to be exchanged and interact without a single point of failure. IPFS creates trustless node interrelations.
The property of linkability allows one to determine whether any two signatures have been produced by the same member (under the same private key). The identity of the signer is nevertheless preserved. One of the possible applications can be an offline e-cash system.
The chain of blocks that prevails in the case of a fork (see “Fork”, above.) When miners “chain” a new block to the previous one, the way the blocks are “chained” has a value. The harder the work done in chaining a block (in PoW blockchains), or the closest a block complies to the consensus rules, the higher the score is for that piece of the chain. In the event of a fork, when a node has more than one new block or blockchain to choose from to update itself, the node calculates the cumulative “score” generated when creating each chain, and chooses the chain with the highest score (in Proof of Work this “score” is referred as “difficulty”, and the chain with the highest cumulative difficulty is the chosen one.) In this way, nodes in a P2P network can reach the same decision without communicating with each other, but simply using the same algorithm to evaluate the options presented to them.
A full node that keeps the full copy of the blockchain in real-time but has additional roles such as participating in governance and voting. On cryptocurrencies with masternodes such as DASH, they are a key component to the functioning of the blockchain network.
A temporary cache of transactions stored by a node that will exist until each transaction is incorporated into the blockchain. When users submit a transaction to the P2P network, each node receives and validates the transaction and, before rebroadcasting it to the rest of the network, keeps a copy of it in a local queue called a “mempool”. Once the transaction is included in a new “chained” block, the node first executes the transaction, updating the status of its copy of the blockchain, and then removes the transaction from its mempool.
Multiple tokens can be secured on a blockchain, but normally only one token is used to rewards participants and miners on the networks and pay the transaction fees, this token is the Native token.
A currency that has no history recorded on a ledger of when it was minted, or how it has changed hands, but is later on represented as tokens on the blockchain, e.g., Fiat currency.
An external data feed/source of info coming from outside the blockchain from the real world. Oracles work as a bridge between the real world and the blockchain by providing data to the smart contracts.
The ordering of all nodes in the registry used to assign a set of preferred peers to each node. Each node compute its peer filter, and connect to the assigned nodes. When a node publishes receipts, the receipts it is allowed to publish must come from one of its assigned peers at the time the receipt was created.
A consensus mechanism in a private blockchain which essentially gives one entity (or a specific number of entities) with one particular private key the right to make all of the blocks in the blockchain. This is similar to root certificate authorities used in TLS/HTTPS.
Proof of Capacity (POC) is a consensus mechanism used in blockchains that allow the mining devices in the network to use their available hard drive space to decide the mining rights.
The Proof of Participation consensus equally distributes decision power and rewards amongst every node in the federation that contributes to a blockchain’s operation. The protocol only lets new people into the federation slowly (and prioritizes those willing to stake the most). It measures the “participation” of nodes by whether they are rebroadcasting transactions and blocks, and kicks out the nodes that aren’t doing their job.
Miners still process and validate transactions, but do so by proving that they have ownership of a certain amount of the asset, rather than by performing energy-intensive computations.
A network on the global internet allowed to participate in all available transactions and participate in the consensus protocol to help determine who gets to add blocks on the chain and maintain the shared ledger. E.g., just like a public road has open access to anyone.
Refers to a method that allows a sender to replace a “stuck” or unconfirmed transaction with a new one that uses a higher fee. This is done to make sure a transaction confirms as quickly as possible. The “replacement” transaction uses the same inputs as the original one. This is not considered a double spend, as the receiving address(es) typically remain the same.
To measure a node’s participation in ZooBC, when exchanging information in the Peer to Peer network, nodes acknowledge having received information from another node by sending back a digitally signed receipt. Once a node has collected enough receipts and is its turn to create a block, it can include in the metadata of the block a subset of the receipts it has collected. This can be later used to prove, at consensus level, that the node has in fact participated in the network, thus earning participation score.
A type of digital signature that can be performed by any member of a group (1-of-M). One of the security properties of a ring signature is that it should be computationally infeasible to determine which of the members’ keys was used to produce the signature.
A real-time gross settlement system, currency exchange, and remittance network created by Ripple Labs Inc. Ripple is built upon a distributed open-source protocol and supports tokens representing fiat currency, cryptocurrency, commodities, or other units of value such as frequent flier miles or mobile minutes.
The work a node does to replace the last blocks when it realises to be in a fork of the blockchain as it receives a new chain that’s longer (has higher cumulative difficulty) than its current active chain. Reorganisations happen when a node realises that what it thought was the canonical chain turned out not to be. When this happens, the blocks in the latter part of its chain (i.e. the most recent transactions) are reverted and the transactions in the newer replaced blocks are executed. All reorgs have a “depth,” which is the number of blocks that were replaced, and a “length,” which is the number of new blocks that did the replacing.
Schnorr proposes to give users a new way to generate the private and public keys critical to cryptocurrencies. It replaces the Elliptic Curve technique currently used to generate keys with the Schnorr technique. This update increases both privacy and security by grouping together MultiSig and regular transactions in the same category, allowing the blockchain process to more transactions and hiding whether or not a transaction is MultiSig or not.
SDK stands for Software Development Kit. It is a set of libraries and tools for various programming languages that are used by developers to implement applications that interact with the blockchain
An important Bitcoin protocol that removes the signature information, otherwise known as the ‘witness information’ and storing it outside the base transaction block. It enables a greater number of transactions to fit within a block. It also makes the lightning network and better scripting possible.
A family of cryptographic hash functions published by the National Institute of Standards and Technology (NIST) as a U.S. Federal Information Processing Standard (FIPS). A cryptographic hash function is special because it maintains certain desirable properties vs. a non-cryptographic hash function.
Emerging mechanisms that allow tokens and other digital assets from one blockchain to be securely used in a separate blockchain and then be moved back to the original blockchain if needed. Sidechain functionality holds tremendous potential to enhance the scalability of existing blockchains.
A now-defunct marketplace on the Darknet (see above) that was shut down by the FBI. It was best known for selling drugs and other illegal products and accepting Bitcoin as a form of payment.
Self-running computer code that enforces a set of pre-set rules that later cannot be changed, therefore this is like a contract between two or more parties that is enforced digitally on the blockchain.
The maximum time after the previous block that can be waited for a new block to be created.
After this time, all remaining Blocksmiths can legally submit a block to the network, regardless of their computed SmithTime.
The scaling factor which is multiplied into an account’s SmithTime calculation.
When new blocks are being broadcast too frequently, it is increased; when new blocks are too slow, it is reduced.
A user’s funds that are locked or held as guarantee. Mostly referred in “Proof of Stake” blockchain, the stake is the economic purpose to provably commit to a promise that the user won’t sell the staked tokens for a pre-established period of time.
A mechanism that allows interactions to be conducted off the blockchain without significantly increasing the risk of any participant. Moving these interactions off of the chain without requiring any additional trust can lead to significant improvements in cost and speed. State channels work by locking part of the blockchain state so that a specific set of participants must completely agree with each other to update it.
A Sybil attack is a kind of security threat on an online system where one person tries to take over the network by creating multiple accounts, nodes or computers. For example a Sybil attack can take place when somebody runs multiple nodes on a blockchain network. Attackers may be able to out-vote the honest nodes on the network if they create enough fake identities (or Sybil identities). They can then refuse to receive or transmit blocks, effectively blocking other users from a network.
An alternative blockchain network that runs similar software, but is not meant for general use by the majority of the users. It is used to test new code and doesn’t transact any real money or value. Allows developers to experiment and learn.
Unlike standard “t-out-of-n” threshold signature, where t of n users should collaborate to decrypt a message, this variant of a ring signature requires t users to cooperate in the signing protocol. Namely, t parties (i1, i2, …, it) can compute a (t, n)-ring signature, σ, on a message, m, on input (m, Si1, Si2, …, Sit, P1, …, Pn).
In addition to the previous scheme, the public key of the signer is revealed (if they issue more than one signatures under the same private key). An e-voting system can be implemented using this protocol.
A transaction is a set of instructions that a blockchain user prepares and signs in a client application. The user then broadcast the transaction to the network. Nodes in the network receive the transaction, execute it, and incorporate it with others into a block.
Refers to the ability of smart contracts or scripts on a Blockchain to perform calculations and enforce complex rules that most general-purpose programmable computers are currently capable of. This means that the programming language should support (or emulate) features such a conditional branching and storing-data-in-memory in order to satisfy Turing’s concept of a complete machine. In the past, not all computers, even those that are programmable (e.g., Casio calculator) are Turing complete. Not all Blockchains have virtual machines that are Turing complete, even if they do support some form of scripting or smart contracts.
Certain blockchain systems such as Bitcoin use the UTXO model. In this model, the Unspent Transaction Output describes some digital money that has been sent from one wallet address to another but has not yet been “spent” by the receiver (i.e., transferred from the receiver to somebody else). Therefore, the outputs of a blockchain transaction are represented as different unique notes/bills (e.g., $1 or $10 bill), and this helps prevent double-spending each UTXO or “digital note” is accounted separately by such a blockchain system.
Cryptocurrency transactions are confirmed at regular intervals. New transactions have zero confirmations, which means they have not been verified yet and are less reliable.