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ReturnValues Blockchain word cards

By Seungwon Go, CEO & Founder at ReturnValues (

As the premier Blockchain expertise company, ReturnValues distributes own manufactured Blockchain word cards to contribute the right ecosystem for the Blockchain.


Data forgery prevention technology based on distributed computing technology. It is a distributed ledger that divides a block containing user’s transaction data into a chain type with P2P method. Nobody can modify it arbitrarily, and everyone can view all blocks. The first block is called the genesis block.


This means decisions are made by majority agreement, not by centralized organizations or a system is managed by a number of distributed nodes, rather than by a centralized server. The degree of decentralization is judged by the block create permission and the in/external agreement procedures of the network.

dApp(Decentralized Application)

This refers to applications that operate on distributed computing systems using smart contract in blockchain. In addition to smart contract, software linked to smart contracts is included in the scope of the dApp.


Transaction per Second, which is the number of transactions that can be processed per second and is an indicator that evaluates the speed of the blockchain. The current TPS can be calculated as the number of transactions in the last block/block generation time. Measure can vary depends on multiple conditions.

51% Attack

In the PoW network, an attack that creates blocks at a faster rate by holding more than 51% hash power of the entire blockchain network and make other nodes to adopt a blockchain containing falsified data by manipulating the transaction history of a blockchain.


A word that refers to the technical limit of the blockchain. The theory is it can solve two out of three things: scalability, security, and decentralization, but it can’t satisfy all of them at this time. By reducing the number of nodes and speeding up the agreement, you gain scalability, but less security.

Smart Contract

A programmable digital contract that is used to create applications operating on a blockchain platform. In digital contracts based on the blockchain, transactions and contracts can be performed. Ethereum has become widely used, supporting the turing complete language in the creation of digital contracts.


The term means a ‘quarter’ like a fork. It refers to developers copy a whole code of software sources so develop independent software. In the blockchain, blocks are listed in chronological order and can be divided into two or more blocks if they occur at the same time or if there is another problem.

Soft Fork

A blockchain update that ensures previous and new versions of the blockchain are compatible. Users can continue to use it without updating, but mining nodes must be updated to proceed. These updates require more than half the consent of existing mining nodes and can be compatible with previous blocks.

Hard Fork

This is an update that must be made by all mining and user nodes. Because it is not compatible with the previous version, it will exist apart from the old chain. An example of this is when an agreement has not been reached with the existing chain so it is separated or has an independent network.


In a blockchain adopting the PoW algorithm, creating blocks is called mining. the miner calculates a nonce that derives a value lower than the previous hash value using computational power. The miner who first discovers this nonce is given the right to create blocks and the compensation for mining.


This means a unit of individuals that makes up the network of the blockchain. Nodes participating in the network play role in transferring transactions to other users and creating blocks through the validation of transactions. In a public network, anyone can become a node whenever they want.

Token Economy

Since there is no central entity in the public blockchain, users should be allowed to voluntarily participate in the network to maintain a distributed network. To do this, token that is possible to exchange for some form of value is given to users as reward, which is why it maintain these economic systems.


It means a market where you can buy virtual currency. There are various exchanges such as Korbit, Coinone, Bithumb, etc. You can exchange a cryptocurrency into the physical money and also, exchange between the cryptocurrency.


An algorithm that agrees who or how to create the next block. In the network to participate majority, Since the blockchain doesn’t have a central entity, it must determine which node will create the block. Depending on who is given authority to create these block, it can be divide POW, POS, etc.


Through computing operations that find random nonce with proof of Work, grants the approval rights and the ability to create block to the node that completed this task first. Bitcoin and Ethereum are a representative blockchain that adopts POW method.


Proof of Stake allows nodes that have more stakes to have more rights to create block. The rewards for creating blocks are given in the same concept as interest on the equity and unlike the PoW, there is the advantage of less consumption of computing resources. Typical cryptocurrency includes Qtum and PIVX.


Delegated Proof of stake grants the right to create and approve blocks to N nodes elected by vote by giving all nodes the right to vote as much as they have stakes. The advantage of having fewer nodes with rights is that it takes less time to process transactions quickly. Typical cryptocurrency is EOS.


(Byzantine Fault Tolerance) It means a system to prevent failures derived from the Byzantium general dilemma. Consensus style allows some nodes to function normally through a majority agreement, even if they broke or behave maliciously. The consensus include PBFT, DBFT, etc.


(Practical Byzantine Fault Tolerance) It is a kind of BFT algorithm. This method is to select the leader node among the nodes which have authority of making blocks, and the leader collects client requests and forwards them to the rest of the nodes, which then responds to the client again after verification.


(Delegated Byzantine Fault Tolerance) BFT-style consensus that allows network members to select some nodes to delegate the rights to create the blocks, and allows nodes to agree and create blocks, even if some of the selected nodes fail. Typical cryptocurrency is NEO.


Initial Coin Offering. One category of crowdfunding. Usually, This is the way when a company is funded in cash or cryptocurrency. It gives investors a token they develop in return.


Initial Exchange Offering. It is one of the fund raising methods disclosing through exchanges. This is a way to obtain funds by selling token, which has not yet been listed through the exchange and because the exchange validates the project, it is a financing method that ensures investor confidence.


Security Token Offering. It is a way to get funding by selling a token of the nature of the securities. An investor who owns this token can hold as much stakes as a token. Because securities are protected by law, companies must comply with the securities laws of the authorities, and investors can invest safely.


Know Your Customer. It is an identification system of investor. If each government makes a request to a company for trading customers, the company will have to present the information and thus requiring investors to confirm their identity.


Anti Money Laundering. It is a money laundering prevention system to prevent laundering of criminal funds using financial institutions. This is a category that encompasses Transaction Monitoring System(TMS) and Know Your Customer (KYC).

Digital Signature

One way to prove the identity of a sender in a network. If the sender sends a message that is encrypted with its private key to the recipient, the receiver can recognize the message from the sender by decoding the message with the public key.

Public key

A digital key used in a digital signature. The value of the key that is released to everyone like its name and created by a public key encryption algorithms into a private key.

Private key

A digital key used in a digital signature. A randomly selected key value created by a cryptographically safe random number generator that satisfied with certain conditions. Unlike public keys, this is the signature key used to sign a message with a key value that is owned only by the sender.


This is the address to which you send and receive cryptocurrency. It’s like account number. In Bitcoin, it is treated as an object with a list of transaction history and is created by encoding the hash values from the public key values. This allows you to identify recipients and senders.


It’s a word that means transactions. Indicates any action that are occurred on the network to process data stored within the blockchain. A word refers to all actions such as the remittance, the distribution of smart contracts and the calling of contract function.

Block Height

In some blockchain platform, it indicates the total number of blocks created from the earliest generated Genesis Block to the currently mined Block. This is to be described as height. For Genesis blocks, block height is marked as zero.


A word that means a transaction delay. Indicates that a transaction processing has been requested state, but hasn’t yet been put into a block and is in an unprocessed state that is kept and queued in a transaction pool. If the fee is too low or the over-transaction is occurred, the pending is long maintained.


In the PoW that creates blocks of Bitcoin, this value is a hexadecimal value that regulates the computational speed to avoid monopoly in computing operations and to fit block creation cycle. The difficulty is determined by substituting this value for the block generation difficulty formula.


In the PoW, a value that is set to regulate the creation of a block at a fixed interval. The difficulty of finding Nonce, a random number to derive a hash lower than the target hash is controlled by comparing the original intended block creation time to the actual block creation time.


It is a value that is taken from 0 in the header to derive a hash value smaller than the target value in the PoW. The hash function has a rule that if the input value is the same, the output value is always constant. so when calculating hash values, use this principle to calculate the block hash.

Merkle Root

Top value of the Merkle tree, the structure that Bitcoin manages transactions. The Merkle tree connects the two transactional hash values to a single hash value, which is repeated to create a Merkle root hash value. This value is included in the block header and used to validate multiple transactions.

Time stamp

A time-expression system based on Unix time. it is usually used to control the difficulty of the block depending on the time it is generated and the time it was created. In addition, timestamp server can prove that data exists at a specific time by linked blocks based on a hash.


This function has the characteristic of always returning a value of a fixed length, even if the value of any length is entered, and returning a value of a completely different value if the contents of the inserted value are any different. In addition, the input value is not known through the result value.

UTXO (Unspent Transaction Output)

This refers to a bitcoin transaction that is unused transaction output and that has been deposited but has not yet been used. In the bitcoin, the sum of these will be the balance left by the user. And the creation and extinction of these means transactions.


This term means that a transaction has been processed on a blockchain network. After the transaction is included in the block, a confirm is added for each height increase, and the bitcoin will receive a full remittance after six confirms.


Digital assets based on cryptography. Unlike legal-tender paper issued by the government or the central bank, it is managed by protocols based on cryptography. The value and purpose of each cryptocurrency depend on what you want to achieve.


It was the first digital cryptocurrency in 2009 and was created by an unidentified account acting under the alias of Satoshi Nakamoto. To prevent double payment of digital currency, he used distributed ledger technology (blockchain) that generates computerized proof in chronological order.


Alternative coin. It is a term for alternative cryptocurrency other than Bitcoin, such as Litecoin, Ethereum, Dash and Monero. These coins have different purposes and different ways of operation, and were created to perform functions that Bitcoin cannot do it.


Distributed computing platform for implementing smart contract function based on blockchain. Vitalik Buterin created Ethereum to record various information based on the fact that it was able to record to the blockchain not only currency transaction record but also additional information such as contract.


Cryptocurrency which is adopted Ethereum-based DPoS. It has emerged as an alternative to solve the problem of slow processing speed and high commissions for existing Ethereum. EOS provides a platform that drives the dApp by speeding up transaction processing.


This is a cyptocurrency platform that can be used for payment at an internet shopping mall. It is designed as stable coin to minimize price fluctuations. When prices fluctuate, it controls the demand and supply of coins in circulation and manages the liquidity of its value to serve as the actual currency.


This is a pro-financial remittance platform based on a blockchain. It allows processing of fast remittance using a ripple-consensus that entitles trusted nodes specified as a private blockchain to validate and agree on this block.


IOTA is optimized for M2M applications where machines and machines are connected and interacted so, multiple transactions can be processed with small data. Nodes use a directed acyclic graph (DAG) based Tangle that must generate transactions and validate two previous transactions progressed at the same time.


It is China’s first block chain, and it is a smart asset platform built to achieve a smart economy. Use DBFT to process transactions quickly and to ensure that the blocks are fixed as soon as they are created to prevent fork generation. The goal is to make digital asset management more efficient.


This is transfer platform using zk-SNARKs, a zero-knowledge proof to provide anonymous remittance function that was not provided by the existing blockchain. It supports both accounts that disclose the transaction details and those that can be processed privately.

ERC20 Token

It is a token that created according to suggestion №20 on the Ethereum Request for Comments that define the rules to follow when creating a token in the Ethereum platform. Tokens written by this rule are used as the concept of currency and ICO standard tokens in cryptocurrency projects follow this proposal.



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