Born in New York, raised in Tel Aviv
Shafrira Goldwasser, known to everyone as Shafi, was born on November 14, 1959, in New York City. Her parents were Israeli, and the family soon went back to Israel, where she attended grade school in Tel Aviv. The ACM's biography of her notes that her joint American and Israeli citizenship foreshadowed the two countries that would shape her whole scientific life.
In high school she was drawn to physics, mathematics and literature. Nothing in her early years pointed to computers: she had never written a line of code. After finishing school in Israel she returned to the United States to study mathematics at Carnegie Mellon University in Pittsburgh.
Finding computer science
At Carnegie Mellon she discovered programming almost by accident and quickly fell for it. She especially loved an algorithms and discrete mathematics course taught by Jon Bentley, and she worked on Cm*, an experimental computer built from 50 processors. She graduated in 1979 with a degree in mathematics and science.
A summer internship at the RAND Corporation took her to Los Angeles, and a weekend drive up the California coast took her to Berkeley, where she enrolled in graduate school in computer science without yet knowing what she wanted to study. Her first research, for her master's degree, looked at instruction sets for the new RISC style of computer chip. But she soon fell in with a lively group of young theorists, among them Silvio Micali, and a number theory course taught by Manuel Blum settled her direction. Topics such as prime numbers, quadratic residues, the new RSA encryption system and the problem of flipping a coin fairly over the phone excited her more than anything she had studied. She earned her master's degree in 1981 and her PhD in 1984, with Blum as her advisor.
Mental poker and a new science of secrecy
In 1979 the inventors of RSA had proposed a way to play poker over the telephone, dealing from an encrypted deck so that no one needed a trusted dealer. Another Berkeley professor, Richard Lipton, pointed out a flaw: partial information about the encrypted cards could leak, letting a player cheat. Goldwasser and Micali took up the challenge of hiding every scrap of information, not just most of it.
Their answer, published in 1982 in a paper titled Probabilistic Encryption, changed how the world thinks about secret codes. They showed that a secure system must use randomness: the same message has to have many possible encrypted forms, with the sender choosing one at random each time. If a message always encrypts the same way, an eavesdropper who sees it twice already knows something. They also gave the first rigorous definition of what it means for encryption to be secure, called semantic security: an attacker who sees the scrambled text should learn nothing at all about the message that they could not have guessed without it.
Just as important, they introduced a way of proving security rather than hoping for it. Their method shows that anything an attacker could learn from watching the system, the attacker could have produced on their own, so the system reveals nothing. MIT News described these definitions as remaining the gold standard for security, and the ACM credits the pair with turning cryptography from an art into a science.
Zero-knowledge proofs
After both joined MIT in 1983, Goldwasser and Micali, working with Charles Rackoff of the University of Toronto, asked a question that sounded almost like a riddle. Could someone prove that a statement is true without revealing anything except the fact that it is true? Their 1985 paper, The Knowledge Complexity of Interactive Proof Systems, said yes.
They began by rethinking what a proof is. Instead of a fixed written argument, an interactive proof is a conversation: a verifier asks a series of randomly chosen questions, and a prover answers. If the claim is false, the prover will be caught with overwhelming probability. MIT Technology Review compared it to a mathematical game of 20 questions. A zero-knowledge proof is an interactive proof with a remarkable extra property: the verifier ends up convinced, yet learns nothing else, not even a hint about why the claim is true.
The paper won the very first Gödel Prize, the top award for papers in theoretical computer science, in 1993. It launched a research program that continues to this day. Later work by Goldwasser, Michael Ben-Or and Avi Wigderson, and separately by Oded Goldreich, Micali and Wigderson, showed that a group of people who do not trust one another can jointly compute a result from their private inputs while revealing nothing beyond the result itself. That idea, called secure multiparty computation, grew directly out of zero knowledge.
Building the theory of secure computing
Goldwasser kept opening new fields. With Oded Goldreich and Micali she defined pseudorandom functions and showed how to build them, the reason, the ACM notes, that experts today can say what it means for a block cipher such as AES, the encryption standard used to protect files and network traffic worldwide, to be secure. With Joe Kilian she used the mathematics of elliptic curves to produce short certificates proving that a number is prime, so that the primes chosen for systems such as RSA can be known with certainty to be prime.
Her study of proofs with several provers led, with Uriel Feige, László Lovász, Shmuel Safra and Mario Szegedy, to a surprising link between proofs and the limits of computation: for some hard problems, even finding an approximately good answer is as hard as finding the best one. That 1996 paper earned her a second Gödel Prize in 2001 and helped launch decades of work on probabilistically checkable proofs. With Goldreich and Dana Ron she founded the study of property testing, which checks huge data sets by examining only a few places in them. Later she worked on ways to check the work of untrusted cloud computers, on encryption that stays safe even when part of a secret key leaks, and on hiding how a program works while still letting it run.
How people benefit today
Every time someone types a credit card number into a website, logs into a bank or sends a private message, they rely on public-key encryption that uses randomness in exactly the way Goldwasser and Micali showed was necessary. MIT Technology Review notes that their work exposed a weakness in early systems, including early versions of RSA, that always encrypted the same message the same way, and led to cryptographic standards that require randomized methods. The magazine adds that randomized public-key cryptography was the key to commercializing the internet, since it was the only way to send card numbers online securely. Their definitions are still the yardstick that designers use to judge whether a new encryption system can be trusted.
Zero-knowledge proofs, once a purely theoretical curiosity, now run in real products. Cryptocurrencies use them so that a payment can be checked as valid while the sender, receiver and amount stay private. Blockchain networks use them to bundle thousands of transactions into one short proof that anyone can check quickly. The same idea is being applied to digital identity, where a person could prove they are over 18, or a citizen, without handing over a birth date or a passport number. Security researchers also rely on zero-knowledge and multiparty techniques to protect online voting, auctions and logins.
Goldwasser has also helped bring newer privacy tools out of the lab. In 2016 she co-founded Duality Technologies, which builds products using homomorphic encryption, a technique that lets computers analyze data while it stays encrypted. That makes it possible, for example, for hospitals or banks to pool sensitive records for research or fraud detection without exposing anyone's personal information.
Teacher and leader across two countries
Goldwasser joined MIT in 1983 and in 1997 became the first holder of its RSA Professorship in Electrical Engineering and Computer Science. Since 1993 she has also been a professor at the Weizmann Institute of Science in Rehovot, Israel. With her husband, the computer scientist Nir Shavit, and their two sons, she for many years divided her time between the two institutions, spending stretches of a few years in each country.
She has trained a remarkable line of scientists, including Johan Håstad, Salil Vadhan, Amit Sahai, Tal Malkin, Yael Tauman Kalai and Vinod Vaikuntanathan, many of whom lead the field today. From 2018 until 2024 she directed the Simons Institute for the Theory of Computing at the University of California, Berkeley, which brings researchers from around the world together to work on the hardest problems in computing. She is also a lead scientist on Project CETI, an effort to use machine learning to understand how sperm whales communicate.
Her honors include the 2012 Turing Award with Micali, often called the Nobel Prize of computing, two Gödel Prizes, the ACM Grace Murray Hopper Award, the RSA Award for Excellence in Mathematics, the Benjamin Franklin Medal, the L'Oréal-UNESCO For Women in Science Award, and membership in the National Academy of Sciences, the National Academy of Engineering and the Royal Society.
Jewish background
Goldwasser was born in New York to Israeli parents and grew up in Israel, where she went to school in Tel Aviv, and she holds both Israeli and American citizenship. She is profiled in the Jewish Women's Archive's Shalvi/Hyman Encyclopedia of Jewish Women, which also names her in its article on Jewish women in computer science, and in the Jewish Virtual Library. The Jewish Virtual Library notes that she was the fifth Israeli to win the Turing Award. She has not spoken publicly about religious practice, and this profile makes no claim about it.
Legacy
Before Goldwasser and Micali, building a code meant inventing a clever scheme and hoping no one would break it. After them, cryptographers could define exactly what security means and prove that a system meets that definition. That shift underlies the protection of online shopping, banking, messaging and cloud computing used by billions of people every day.
Her idea of a proof that reveals nothing but its own truth has traveled from a theory conference in 1985 into cryptocurrencies, digital identity and privacy technology. Through her students, her leadership of research institutes in the United States and Israel, and the companies she has helped start, Goldwasser continues to shape how people can share and check information without giving away their secrets.
Sources & further reading
Shafi Goldwasser, A.M. Turing Award Laureates, ACM · Goldwasser and Micali win Turing Award, MIT News · Shafi Goldwasser: The number theory expert who helped revolutionize cryptography, MIT Technology Review · Shafi Goldwasser, Jewish Women's Archive · Shafi Goldwasser, Jewish Virtual Library · Researched from the sources above and checked against them. Spotted an error? Tell us.
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