# David Chaum **Year of birth**: **Country of origin**: **Studied at**: UC Berkeley **Worked at**: **Contributed to**: [[DigiCash]] | [[Elixxir]] | [[eCash]] | ![[Pasted image 20210426194511.png]] David Chaum is considered by many to be the father of the [[cypherpunk]] movement. A prolific academic researcher, Chaum single-handedly created the field of anonymous communications research and invented many cryptographic protocols, including group signatures, mix networks, and blind signatures. In 1990, David Chaum spearheaded the first serious attempt at building private digital money: [[DigiCash]]. DigiCash used novel cryptography to ensure user privacy while solving the double spend problem. The underlying algorithm was known as [[eCash]], first published in 1982 and later improved by other cryptographers. What follows is a simplified description of the eCash algorithm: First, coins are issued to users by a bank. Each coin has a specific denomination and serial number, which are cryptographically signed by the bank. When a merchant receives a coin from a user, the merchant relays the coin to the issuing bank. The bank verifies that the signature over the denomination and serial number is valid and whether the coin has been previously spent. If these check out, the bank ensures that all spent coins are real and haven't been spent before. The merchant is then paid out for whatever the coins were worth. --- David Chaum is a renowned American computer scientist and cryptographer. He is known as a pioneer in [[cryptography]] and privacy-preserving technologies, and widely recognized as the inventor of digital cash. In the 90s, he came up with “ecash,” a [[Crypto (cryptocurrency)|digital currency]] issued by Deutsche Bank. He holds a PhD in computer science from UC Berkeley; his 1982 dissertation, titled "Computer Systems Established, Maintained, and Trusted by Mutually Suspicious Groups,” was recently credited as an early framework for [[blockchain]] technology; he is also known for a number of innovations of [[cryptography]]. His dissertation discussed many concepts like blind signatures, time-stamping chained data and chaining consensus blocks that resemble aspects of today’s blockchain. Throughout the 1980s, Chaum proposed many ideas that emphasized a need for anonymity and privacy in communication, even developing an idea for a secure voting system with end-to-end encryption to prevent fraud. Chaum has maintained his passion for cryptography, privacy technology and digital anonymity into the present day. He is currently leading Elixxir and Praxxis to provide scalable digital sovereignty. Additionally, Chaum has taught at NYU Graduate School of Business and UC Santa Barbara; he has also led a number of breakthrough projects such as the International Association for Cryptologic Research, the cryptography group at the Center for Mathematics and Computer Science in Amsterdam, [[DigiCash]], the Voting Systems Institute and the Perspectiva Fund. In 2020, Chaum launched his latest endeavor: the XX coin, a digital currency that will support [[decentralized]] messaging. Key quote: “I’ve always had a fundamental belief that individuals should control their own digital lives, and to do so, [[Peer-to-Peer (P2P)]] networks are necessary.“