C

Candidate Block

Represents a block a miner is in the process of mining in order to receive the block reward. Can also be known as "temporary block". It can be eventually either validated or discarded by the network.

Call/ API call

When a request from an endpoint is made to an application's server. Through this call information is transferred, processed, and a reply is returned.

Callback

A function that is activated after another one completes. E.g. receiving notifications on events. A callback requires a callback URL to be set.

Callback URL

A URL set upfront where the callback notification will be received, when it's time.

Censorship-resistance

Refers to the property of a cryptocurrency network and dictates that any user can make transactions on the network, as long as they follow the rules set by the protocol, and they cannot modify any already existing transactions.

Centralized

A concept of data and network distribution where these are governed by a single (centralized) entity (server, computer, etc.). Such a centralized system/network always needs a main controlling mechanism, otherwise it cannot operate properly.

Cipher

Can also be seen as "cypher". A method used in the encryption and decryption of values, which can be done either asymmetrically or symmetrically depending on the key type.

Circulating Supply

The number of all crypto coins and tokens that are publicly available and circulating on the market.

Client

A computer/program that sends a request to another program/hardware/software that accesses a service made available by a server.

Co-Custodial Wallet

Defines a type of Wallet which is a mix between Custodial and Non-Custodial. It allows the user to hold and manage their own key(s) and Wallet, but also provides a backup/emergency/recovery service from the provider.

Coin

A coin is digital cash generated via their own independent blockchain.

Cold Wallet

Cold wallet, known also as a "hardware wallet" or "offline wallet", stores the user's address and private key. Since it is not connected to the Internet, it cannot be compromised.

Confirmation

When the network has verified a blockchain transaction through the process of "mining". Once a transaction is successfully confirmed it cannot be reversed or double spent.

Confirmation Time

The elapsed time from submitting a blockchain transaction till the moment it is finally recorded in a validated block.

Contract account

One of the two types of accounts on the Ethereum blockchain. This account is controlled only by code and has no public-private keys involved. Since it uses networks storage, creating an account has a cost. Its execution is triggered by transactions or messages received from other contracts.

CPFP

Stands for Child Pays for Parent - a method used for an unprocessed "stuck" transaction which has too low of a fee, and the receiver has to pay a higher fee by broadcasting a new transaction and spending UTXO from the "stuck" transaction. This way the miners are motivated to mine the low-fee transaction ASAP.

Credit

Used to define spending limit on requests. Credits depend on the subscription tier you have to a Crypto APIs' product.

Cryptocurrency

A digital asset/currency which is verified by cryptography and hence is nearly impossible to counterfeit. It uses the blockchain technology and is distributed, exchanged and traded in a Peer-to-Peer network. Cryptocurrency payments and transactions are digital entries in an online database (ledger).

Cryptography

The study of utilizing numerical hypotheses and calculations so as to encrypt and decrypt data.

Custody/Custodial Wallet

Is also known as "custodial service" - the holding of assets on behalf of a client. In regards to cryptocurrency, it refers to when a third party holds the private keys to a user’s funds, which would make that third party the only one who can send and receive these coins. Refers also to a type of Digital Wallet.