David Lee Chaum (born 1955) is an American computer scientist, cryptographer, and inventor. He is known as a pioneer in cryptography and privacy-preserving technologies, and widely recognized as the inventor of digital cash. His 1982 dissertation Computer Systems Established, Maintained, and Trusted by Mutually Suspicious Groups is the first known proposal for a blockchain protocol. Complete with the code to implement the protocol, Chaum's dissertation proposed all but one element of the blockchain later detailed in the Bitcoin whitepaper. He has been referred to as the father of online anonymity, and the godfather of cryptocurrency. He is also known for developing ecash, an electronic cash application that aims to preserve a user's anonymity, and inventing many cryptographic protocols like the blind signature, mix networks and the Dining cryptographers protocol. In 1995 his company DigiCash created the first digital currency with eCash.: 65–70  His 1981 paper, Untraceable Elect