- Person
- Shafi Goldwasser
- Lived
- b. 1959
- Field
- Computer science, cryptography
- From
- American-Israeli
The story
A traditional proof is a written argument that anyone can read and check. In the early 1980s Shafi Goldwasser and Silvio Micali, newly appointed at MIT, began to imagine a different kind of proof: a conversation. In what they called an interactive proof, a verifier asks a series of randomly chosen questions and a prover answers them. If the claim is false, the prover will be caught with overwhelming probability. MIT Technology Review likened it to a mathematical game of 20 questions.
Working with Charles Rackoff of the University of Toronto, they then asked a startling question. Could a prover convince a verifier that a statement is true without giving away anything else, not even a hint about why it is true? Their 1985 paper, The Knowledge Complexity of Interactive Proof Systems, showed that the answer is yes and gave the first example of such a zero-knowledge proof. The key idea was a precise test: a proof reveals no knowledge if everything the verifier sees during the conversation is something the verifier could have produced alone.
MIT News called zero-knowledge proofs a striking new philosophical idea that gave cryptographers the language for talking about the security of protocols by controlling the leakage of knowledge. The paper won the first Gödel Prize, the leading award for papers in theoretical computer science, in 1993. Later work by Goldwasser, Michael Ben-Or and Avi Wigderson, and by Oded Goldreich, Micali and Wigderson, built on it to show that a group of people who do not trust each other can compute a joint result while keeping their own inputs secret.
For years zero knowledge seemed purely theoretical. Today it runs in real systems. MIT Technology Review notes that zero-knowledge proofs have been combined with blockchain technology to create cryptocurrencies in which transactions can be verified as valid while their details stay private. Similar proofs are used to compress large batches of transactions into one short certificate, and they are being applied to digital identity, so a person might prove they are an adult or a resident without revealing their birth date or address.
The work was a central part of the 2012 A.M. Turing Award that Goldwasser and Micali shared.
Why it matters
Zero-knowledge proofs let people and computers prove facts, such as a valid payment or an age, without exposing private data, and now protect privacy in digital money and identity systems.
About Shafi Goldwasser
Computer scientist who co-invented probabilistic encryption and zero-knowledge proofs, giving the mathematical foundations for secure online life. Turing Award 2012.
More about Shafi Goldwasser
Sources
- Goldwasser and Micali win Turing Award MIT News
- Shafi Goldwasser: The number theory expert who helped revolutionize cryptography MIT Technology Review
- Shafi Goldwasser, A.M. Turing Award Laureates ACM
Another act of tikkun olam. This is part of tikkun olam, the Jewish idea of repairing the world, and every one of us can add to it.