A blockchain is a distributed database that is shared among the nodes of a computer network. The goal of blockchain is to allow digital information to be recorded and distributed, but not edited. In this way, a blockchain is the foundation for immutable ledgers, or records of transactions that cannot be altered, deleted, or destroyed. The innovation with a blockchain is that it guarantees the fidelity and security of a record of data and generates trust without the need for a trusted third party. 

Blockchain technology was first outlined in 1991 by Stuart Haber and W. Scott Stornetta, two mathematicians who wanted to implement a system where document time stamps could not be tampered with. Working at Bellcore Labs in the 1990s, scientists Stuart Haber and Scott Stornetta were allowed to pick their own research projects. For Stornetta, a problem worth solving was the authentication of digital documents: how could you be sure the version you were looking at had not been altered from its original?