A common ticker symbol used to designate Bitcoin.

Byzantine Fault Tolerance

A condition of a computer system, particularly distributed computing systems, where components may fail and there is imperfect information on whether a component has failed. The term takes its name from an allegory, the "Byzantine Generals Problem", developed to describe a situation in which, in order to avoid catastrophic failure of the system, the system's actors must agree on a concerted strategy, but some of these actors are unreliable.

Certificate Authority (CA)

In cryptography, a certificate authority or certification authority (CA) is an entity that issues digital certificates. A digital certificate certifies the ownership of a public key by the named subject of the certificate. This allows others (relying parties) to rely upon signatures or on assertions made about the private key that corresponds to the certified public key.

Chain Reorganization

Chain reorganization is a client-local phenomenon where a client discovers a new difficultywise-longest well-formed blockchain which excludes one or more blocks that the client previously thought were part of the difficultywise-longest well-formed blockchain, resulting on orphan blocks.

Closed Source

Proprietary software, also known as non-free software, is computer software for which the software's publisher or another person reserves some rights from licensees to use, modify, share modifications, or share the software.

Cold Storage / Cold Wallet

Cold storage in the context of Bitcoin refers to storing Bitcoins offline and spending without the private keys controlling them ever being online. This resists theft by hackers and malware, and is often a necessary security precaution especially dealing with large amounts of Bitcoin. For example, a Bitcoin exchange which offers an instant withdrawal feature, and might be a steward over hundreds of thousands of Bitcoins. To minimize the possibility that an intruder could steal the entire reserve in a security breach, the operator of the website keeps the majority of the reserve in cold storage, or in other words, not present on the web server or any other online computer. The only amount kept on the server is the amount needed to cover anticipated withdrawals in one day.

Command-Line Interface (CLI)

A command-line interface (CLI) processes commands to a computer program in the form of lines of text. The program which handles the interface is called a command-line interpreter or command-line processor. Operating systems implement a command-line interface in a shell for interactive access to operating system functions or services.

CPU Miner

Either refers to (1) a bitcoin miner which uses a computer's CPU, or (2) a simple client program that performs Pooled Mining or solo mining.


A cryptocurrency, crypto currency or crypto is a digital asset designed to work as a medium of exchange wherein individual coin ownership records are stored in a ledger existing in a form of computerized database using strong cryptography to secure transaction records, to control the creation of additional coins, and to verify the transfer of coin ownership. It typically does not exist in physical form (like paper money) and is typically not issued by a central authority.

Cryptographic Hash Function

Cryptographic hash function is a special class of hash function that has certain properties which make it suitable for use in cryptography. It is a mathematical algorithm that maps data of arbitrary size to a bit string of a fixed size (a hash) and is designed to be a one-way function, that is, a function which is infeasible to invert.