Page 10 - FIGI: Security Aspects of Distributed Ledger Technologies

2 Glossary of Terms

Altcoin Any crypto-currency that exists as an alternative to Bitcoin
API Application programming interface (part of a remote server that sends requests and
receives responses)
Bitcoin The first, and most popular, crypto-currency of the modern era using a blockchain
Blockchain (Public) A mathematical structure for storing digital transactions (or data) in an immutable, peer-to-
peer ledger that is incredibly difficult to fake and yet remains accessible to anyone.
Casper Consensus algorithm combines POW and POS. It is planned for Ethereum to use Casper as
a transition to POS.
Centralized Maintained by a central, authoritative location or group
Crypto Asset Anything of value, which could be traded, and which is represented as a token on a block-
chain. These include security tokens, utility tokens, and payment tokens.
Cryptographic Hash Function A function that returns a unique fixed-length string. The returned string is unique for every
unique input. Used to create a “digital ID” or “digital thumbprint” of an input string.
dApps Decentralized Applications
DAO A decentralized autonomous organization is an organization that is run through rules
encoded as computer programs called smart contracts
DDos Attacks 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.
Decentralized The concept of a shared network of dispersed computers (or nodes) that can process trans-
actions without a centrally located, third-party intermediary.
Digital signature A mathematical scheme used for presenting the authenticity of crypto-asset assets
Distributed Ledger A database held and updated independently by each participant (or node) in a large net-
work. The distribution is unique: records are not communicated to various nodes by a cen-
tral authority.
ERC Ethereum request for comments standard
Ethereum Blockchain application that uses a built-in programming language that allows users to build
decentralized ledgers modified to their own needs. Smart contracts are used to validate
transactions in the ledger.
Fork Alters the blockchain data in a public blockchain.
Gas (Ethereum) Measures how much work an action takes to perform in Ethereum. Gas is paid to miners as
an incentive for adding blocks.
Genesis Block The initial block within a blockchain
Github A web-based hosting service for version control using git
Gossip Protocol A gossip protocol is a procedure or process of computer-computer communication that is
based on the way social networks disseminate information or how epidemics spread. It is a
communication protocol.
Governance The administration in a blockchain company that decides the direction of the company
Hard Fork Alters the blockchain data in a public blockchain. Requires all nodes in a network to upgrade
and agree on the new version.
Hash function A function that maps data of an arbitrary size.
Hyperledger Started by the Linux Foundation, Hyperledger is an umbrella project of open source block-
chains
Hyperledger Fabric Hyperledger project hosted by Linux which hosts smart contracts called chaincode.
Initial Coin Offering (ICO) The form in which capital is raised to fund new ventures. Modeled after an Initial public
offering (IPO). Funders of an ICO receive tokens.
Merkle Tree A tree in which every leaf node is labelled with the hash of a data block and every non-leaf
node is labelled with the cryptographic hash of the labels of its child nodes.

8 Security Aspects of Distributed Ledger Technologies