Adi Shamir (Tel Aviv, Israel, 1952) received a BSc in Mathematics from Tel Aviv University and went on to obtain a PhD in Computer Science in 1977 from the Weizmann Institute of Science. From 1977 to 1983, he was a researcher and assistant professor at MIT. It was there he met Ron Rivest and Len Adleman, with whom he went on to invent the RSA algorithm. After completing his stay at MIT, he returned to the Weizmann Institute, where he now holds the Borman Professional Chair of Computer Science.
As well as his work on RSA, secret sharing and differential cryptanalysis, the Israeli scientist succeeded in breaking the Merkle-Hellman cryptosystem, one of the first public-key schemes in existence. He is also the designer of the TWIRL and TWINKLE factoring devices, the author of identify-based cryptography and inventor of visual cryptography, based on breaking up an image – which could be a text – such that the resulting pieces appear to be a random scattering of black and white pixels.
The BBVA Foundation Frontiers of Knowledge Award in the Information and Communication Technologies category goes, in this tenth edition, to Shafi Goldwasser, Silvio Micali, Ronald Rivest and Adi Shamir for their “fundamental contributions to modern cryptology, an area of a tremendous impact on our everyday life,” in the words of the jury’s citation. “Their advanced crypto-protocols enable the safe and secure transmission of electronic data, ranging from e-mail to financial transactions. In addition, their work provides the underpinning for digital signatures, blockchains and crypto-currencies,” like Bitcoin.
The work of Goldwasser, Micali, Rivest and Shamir, the citation adds, “is crucial to the fabric of our connected digital society. Every time we log in to social media, purchase goods online, or vote or sign electronically, we leverage the technology developed by their research.”
For the jury, the rise of today’s digital age could never have happened without techniques that ensure the secure exchange, use and storage of information. Cryptography is an “invisible” technology that is nonetheless indispensable for today’s society. Over the space of four decades, the new laureates have not only laid the foundations of this complex field, but have also continued to enlarge it with breakthroughs that exploit the possibilities of the vast wealth of information now at our command, the famous Big Data, or have driven the development of potentially world-changing technologies like crypto-currencies.
“Human societies have always needed secure communication,” the jury remarks, and this need has become increasingly acute. The design of openly available communication protocols accordingly represents “a great research challenge, which was tackled superbly by the awardees.”
In 1978, Adi Shamir and Ronald Rivest, together with Leonard Adleman, created the RSA algorithm (whose initials correspond to their surnames). The “first of the secure protocols that defined the face of modern cryptography,” as the jury terms it, RSA is what is known as a “public-key” encryption system, because each user has two keys: a public key, used to encrypt the message; and another one known only to the receiver. The encryption process is based on a mathematical problem intractable for today’s computers – in this case the factoring of a multi-digit number – without the aid of the other, private key. RSA is still a widely used protocol, particularly in combination with other techniques.
Shamir and Rivest, now working respectively out of Israel’s Weizmann Institute and the Massachusetts Institute of Technology (USA), arrived at this first breakthrough while collaborating closely at MIT, and in the forty years since then have continued to contribute actively in diverse areas of cryptography.
Goldwasser was then studying at Carnegie Mellon University (USA) and Micali at the Sapienza University of Rome. A few years later, in 1982, the two coincided on a doctorate course at the University of California, Berkeley (USA) and embarked on a fruitful collaboration whose first big result would lay the theoretical foundations of the field – the mathematical demonstration of when an encryption method is genuinely unbreakable.
As Micali explained in a phone conversation last night, “for thousands of years people have been trying to encrypt messages, but these were only secure until the moment they stopped being so, because someone had unlocked the code. RSA proposed an encryption scheme that no one could to break, but at the same time no one could prove was unbreakable. To prove a thing is secure, you need to go further. You want to be sure that no future attack can succeed. Our contribution was to apply a rigorous method to ensure that if someone wants to understand part of an encrypted message, they would first have to solve a mathematical problem that has stood unsolved for hundreds of years.”
Following on from these seminal achievements, Goldwasser and Micali, together and separately, “have expanded the scope of cryptography beyond its traditional goal of secure communication,” in the view of the jury, with developments that have helped build today’s flourishing digital society by allowing users to collaborate, share information and shop online without sacrificing security.
For instance, both scientists contributed (with Charles Rackoff) to the development of the “zero-knowledge proof,” which shows that it is possible to convince your interlocutor of the truth of something without revealing what that something is. The result is an algorithm that underlies a wide range of applications from authentication processes to Bitcoin transactions. Talking last night after hearing the award, the two laureates offered as examples logging in to a social network with your password, ordering transactions in your online bank account, or making payments with crypto-currencies.
“In our daily lives, any ‘password’ we type or digital signature we use is protected by techniques based on our work,” says Micali.
Goldwasser, meantime, singled out another contribution, vital to properly harness the power of big data. When a series of organizations pool their databases to extract the greatest possible amount of information from the resulting aggregate, but without disclosing the identity embedded in the data.
She believes it is vital that citizens learn to value their personal data, and stop giving them away for free, insisting that, with today’s cryptographic tools, privacy and security are readily compatible. She is also convinced of the area’s huge untapped potential: “We have effective cryptographic methods that are still not being used… IT firms should do more to build systems to make use of the beautiful ideas we have come up with in the cryptographic field that have never been implemented.”
Rivest and Shamir too have continued to contribute valuable ideas and solutions. Rivest, specifically, created a popular algorithm with the ability to check that a given file – downloaded from the internet, for instance – has not been tampered with. Shamir, meantime, has developed the area of differential cryptanalysis, a method for decrypting secret keys.
On being informed of the award, Rivest remarked on how much cryptography, and society with it, has changed during his career: “In the late 1970s, we didn’t even have the World Wide Web, it was impossible to imagine that our method would become what it is today… Right now, each time we make an online purchase, the transaction’s security is based on our encryption technology, and it is thanks to this technology that we can be sure we are talking to Amazon, and vice versa.”
The bitcoin and blockchain technologies are another topic currently occupying these four experts. For Rivest, “Bitcoin is an interesting technology, but the truth is there is a lot of hype associated with the phenomenon and it is too early to say whether it will become a reliable system capable of ushering in the new digital economy.”