Blockchain Applications in Security

Blockchain technologies are based on cryptographic algorithms and were initially proposed as a peer-to-peer data transfer mechanism. Often referred to as distributed ledgers, these technologies are decentralized databases in which all records are stored in blocks and linked by cryptographic algorithms called hash functions. Cryptographic hash functions are algorithms that take as input a message of arbitrary length and output a fixed-length digest of the message. It is well known that these cryptographic algorithms are developed for the purpose of providing information integrity since any change in the input message results in a drastic change in the message digest. Therefore, hash outputs are considered a “fingerprint” of a given message. This property makes hash functions the core of blockchain technology since information for each new record in a blockchain is encapsulated into a block, and meta-data from the hash output of the previous block is always incorporated into the hashing process of a new block.