A brief history of blockchain technology

Stuart Haber and W. Scott Stornetta envisioned the concept of a blockchain in 1991. They started by working on a blockchain secured by cryptography. The core of the idea is that the content of each block (text, numbers, date and time etc.) would be impossible to alter, after the block has been mined.

Something called "Hash trees" was incorporated into the system in 1992. A "Hash" is a map of information written as a unique string of characters with a set length. This identifier helped make the system more efficient by removing confusion, manipulation, and duplication, resulting in more documents per block. The original concept of a hash tree is named after Ralph Merkle, who patented it in 1979. Today, we use the terms "Hash trees" and "Merkle trees" interchangeably.