Short answers, pulled from the story.
David Lee Chaum was born in 1955 to a Jewish family living in Los Angeles, California. He pursued his doctoral studies at the University of California, Berkeley and earned his degree in computer science in 1982.
David Chaum published his dissertation titled Computer Systems Established, Maintained, and Trusted by Mutually Suspicious Groups in 1982. The document contained code for a protocol that would later be recognized as the first blockchain proposal and laid out how nodes could reach consensus while remaining mutually suspicious of one another.
Chaum introduced the concept of secure digital cash through an 1983 paper that described blind signatures which allowed users to obtain currency from a bank without revealing their identity. He founded DigiCash in Amsterdam in 1990 to commercialize these ideas and sent its first electronic payment in 1994 before the company filed for bankruptcy in 1998.
In 1981 Chaum proposed an anonymous communication network through a paper titled Untraceable Electronic Mail, Return Addresses, and Digital Pseudonyms. His mix networks allowed senders to submit encrypted messages to servers that reordered and obfuscated them and he introduced DC-Nets in 1988 as another type of anonymous communication system solving his Dining Cryptographers Problem.
The city of Takoma Park, Maryland used Scantegrity during its November 2009 election which marked the first time a public sector election employed any cryptographically verifiable voting system. This innovation followed Chaum's earlier contributions including SureVote in 1991 and Random Sample Elections in 2011.