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Blockchain just refers to an online database shared across a network of computers, but it differs from other databases in a number of important ways. For security, once a record has been added to the chain by a legitimate entity (such as a veterinary clinic, laboratory, or specialty center), it is very difficult for others to change. For consistency, the network makes frequent checks to ensure that all copies of records are the same across the entire network.

In a blockchain, individual records are bundled together into blocks, and then linked sequentially within the chain. The three parts of the process are thus:

 the record

 the block

 the chain.

For any given transaction, the process involves recording the details of the individual transaction (record), including digital signatures for each party. The computers in the network, called nodes, then verify the details of the record to make sure it is valid. Accepted records are then added to a block and then the block of records is ready to be added to the chain. Each block contains a unique code, called a hash, that identifies where it belongs when assembled into a chain. These hash codes are created by a mathematical formula and contribute to the security of the system. In the final step, the blocks are added to the chain, and the hash codes connect the blocks in a specific order.

Any change to the original record, no matter how miniscule, would be detected and would warrant the generation of a new hash code. That change to the hash code alters the blockchain, making it extremely difficult for hackers to make changes that are not immediately detected within the network. It's not impossible but attempting to change all the hash codes within the chain would require phenomenal computing power, making it much more secure than current systems.

A blockchain database is decentralized and computers in the network are nodes, so there is no master computer in the system. With a decentralized network, all the participating nodes can access the information and compete to be the next to add to the database, so the system sets up tests of trustworthiness. These tests are referred to as consensus mechanisms and require network members to prove themselves before they are allowed to add to the chain.

To make sure only authorized users have access to the information, blockchain systems use cryptography‐based digital signatures to verify identities. Account holders have private keys that are nearly impossible for hackers to discern, but public keys can be generated for information sharing. In this way, anyone with a public key can receive information (such as a disease registry or insurance company), but only those with a private key can alter that information (such as permitted medical professionals, laboratories, etc.). Third parties, such as pet owners, can be given limited access to records, while the audit trail capability of blockchain means there is complete documentation of the creation, modification, and attempted deletion of records.