History

A blockchain is a digital list of data records or blocks, using cryptography to secure the integrity of the data. The blockchain record is a cumulative log of all transactions that have ever been made to or from a wallet. Each record contains a unique hash linked to the previous record. Because the records are cumulative, the blockchain is inherently resistant to modification and provides a secure way to store data. Each record is secured with cryptographic signatures to serve as tamper-evident proof of data integrity. The most common use of blockchains are for auditing, secure document storage, and provenance tracking. Examples include the bitcoin blockchain, Ethereum blockchain and Hyperledger Fabric blockchains.

Data model

A blockchain consists of a list of "blocks" containing transactions. Each block is identified with a unique cryptographic hash that serves as a link to a previous block in the chain. The design of blockchains allows the stored data to be arranged in a chronological order.

When each block contains a link to a previous block, the chain of blocks becomes a chain of pointers. A pointer is essentially a reference to or link to other data. Because a blockchain is a sequentially arranged digital data structure, it is often referred to as a linked list. Each block is similar in nature to a document, an image or an audio file.

Structure

Blockchain is a sequentially arranged data structure that is resistant to modification. It is also resistant to replacement and deletion because each block must follow the data that came before it. A blockchain contains a list of "blocks" in order, and each block contains a list of transactions, and each transaction references the transaction that came before it in the block. Each block also contains a hash of the previous block in the chain.

The data model of blockchain follows a simple and easily understandable data structure that corresponds with a linked list.

Concept

In consensus-based blockchain systems, cryptographic hash, and the Merkle–Damgård construction are used to provide resistance against modifications in the chain. This construction ensures that each block in the chain has a header and a list of transaction data, and when a block has a link to the previous block in the chain it knows the previous block, which makes the system resistant to replacement of older blocks in the chain.

Each block in a blockchain is designed to be linked to a previous block in the chain using a hash of the previous block, and the reverse link is the one that is used when it https://mostbet-bahis-site.com/