Shafi Goldwasser (New York, 1958) and Silvio Micali (Palermo, 1954) have spent a lifetime dedicated to mathematics, computing, and cryptography. They have solved impossible problems, they have won the most important awards and they have even founded their companies: I have decided to create mine because before waiting for someone else to realize that blockchain can be done in a different way, I roll up my sleeves and I do it me. If not, nobody does it, says Micali.
Now they see how the main technological solution that is proposed to help against the pandemic digital contact tracking could use its cryptographic techniques invented years ago, but hardly anyone has tried yet. It is an example of how implementation processes, also in the world of technology, are slower than it seems: I dont know exactly what the barrier is. To get into the hands of consumers you need a huge consensus from many parties, says Goldwasser. Its interesting why people start using something. Many things must align: necessity, that someone wants to market it and give it a push. Its not just that the math is there and that the technology can be built, but that someone really wants to do it, he adds. This pandemic may be a push to make those solutions more likely in the next.
Cryptography is essential in the functioning of the Internet: it serves to demonstrate that we are who we say we are or to ensure that no one other than its recipient reads our messages. Since the 1980s, Goldwasser and Micali have been working on methods to improve it. Their work jointly won them in 2012 the Turing Prize, the Nobel Prize in Informatics, and in 2018 the BBVA Foundation Frontiers of Knowledge Prize in new technologies. Their work has shown that the recurring drama between privacy and security has solutions that have not been studied until now: I believe in crypto because it can prevent us from being told: Guys, if you want to save yourself, you have to give up all privacy. Is not true. Cryptography allows us to continue living and that there is confidentiality, says Micali.
Micali has his theory about why theoretical advances in technology take so long to reach practical use for consumers: What you learn in school and university is what you apply. If a computer scientist knows from university that there are tools that allow precision and privacy to be combined, when he becomes someone important he applies it. It takes a generation for new employees to know these things. It takes time, he says.
What can Goldwassers and Micalis theories do? Partially resolve the dilemma between privacy of citizens and security for all. We want to maintain privacy and we dont want to find information about you: where you were or at what time, explains Goldwasser. What we are looking for is some sign that, added, serves to know where people are becoming infected or where it is most likely to happen: on the street or indoors, in a large or small room. This cryptography allows calculations with lots of data without any participant seeing them, so privacy is assured.
This is important these days when governments across Europe and around the world are debating how technology can help track down bluetooth contacts to find out if youve been around someone who tested positive for covid-19. In the version that best preserves privacy, notification of exposure is given only on the phone of citizens. It is then up to each person to decide whether to alert the health authorities. But the government has no idea how many possible new cases there are each day (it only knows the calls it receives) or how these contacts have occurred. This is the protocol that Apple and Google support with their technology.
There are countries that believe that this information is insufficient. In Europe, above all, France and the United Kingdom. Both seek solutions so that the Government knows more. But without using Apple and Google technology, it is much more difficult for mobile bluetooth to work well. Cryptography could help: Is it possible to preserve privacy even if you centralize information? The answer is yes. Since the 1980s we have had this type of protocol. Then they were theoretical but now they are practical. It can be done, says Goldwasser.
Goldwasser recently used the metaphor of a puzzle piece in a video conference in Berkeley: If you have a piece of the puzzle and they are well cut, it doesnt reveal anything about the image, but if you put them all together, yes. The piece of the puzzle is the piece of data that you have, he says. If you can put them all together, you will have the result you are looking for without seeing the original data.
The method is to encrypt the individual data and send it to a public server. Without revealing anything, with these encrypted data you can do aggregate calculations, prepare statistics on where people get infected, at what time of day, if it happens at home, in the office or on the street. It is not a complicated type of computing, the type of statistics is not complex, it can be efficiently encrypted, says Goldwasser. The problem is that the coronavirus has come quickly and suddenly. Goldwasser has a company in Israel that is in contact with European governments to be able to do something like this. But it is difficult for it to have results soon. It can be used in more sectors. It must develop. Probably in months, sooner than we think. Someone has to see it, he says.
This type of technology has been used for money laundering, for example. Banks are reluctant to give out customer data to see if someone moves a lot of money between a lot of banks, but this type of encrypted collaboration is more viable. The same can happen with medical data.
For its part, Micali proposes an app that defines the total number of contacts in society. Its objective would be to measure if, with the different phases of lack of confinement, the contacts between people grow rapidly: I open the beach. If the matches range from three on average to 200, I have to worry. Its not just about tracking. The poor government that wants to make a smart policy has the right to know how many encounters take place. But we dont know, he explains. And he adds: The app has no pseudonyms, it has nothing. Only the number of encounters . It would therefore be completely private.
Micalis efforts are also aimed at cleaning up the good name of blockchain: Traditional blockchains are not, they are just called that. I sold something that is no longer sold, but now people want blockchain: well, I erase the name and change it, he says. That makes blockchain somewhat laughable today: It is a myth. There are two or three decentralized, the other 2,000, nothing, he says. As with cryptography for privacy, changes come slowly.
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They tell us: If you want to save yourself from the pandemic, you have to give up all privacy. It is not true | Technology - Explica