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CRIPTO: Cryptography Research Involving Practical and Theoretical Outlooks

Final Report Summary - CRIPTO (CRIPTO: Cryptography Research Involving Practical and Theoretical Outlooks)

The science of cryptography is primarily concerned about keeping data secure. This leads one to consider what is meant by data, what we mean by secure, and when we want data to be secure. The traditional view (popularized in Hollywood movies) is so called communication security; we want to secure data, in the sense of keeping it secret, when it is in transit between two parties across an untrusted communication channel. However, this is just a narrow definition. These days we want to secure data when it is stored, and we want to ensure the integrity of data (i.e. that data is not changed by some adversary). Modern cryptography has provided strong solutions to secure data when in transit (communicated) and when data is at rest (stored); we are only at the infancy of securing data when it is actually in use.

The major advances of the CRIPTO project aim to secure data whilst it is actually being used. We have developed mechanisms to compute using data which is either encrypted, or secret shared. Secret shared data is a form of encryption in which data is split between two or more parties, such that the parties need to all come together so as to recover the data. The CRIPTO project has made advances in general techniques for such computation on encrypted data; as well as contributions in more specific application domains such as e-voting. To understand what we mean, consider the simple case of e-voting we want to compute the result of an election by processing the “encrypted” votes, without ever learning what the actual votes are. This computation of a function on “encrypted” data, is the basic concept which the CRIPTO project generalised to arbitrary functions.

In addition to this specific work the project also examined other forms of cryptographic protocols; for example we helped analyse and design the key exchange scheme which is proposed for use in the next generation of the EMV chip-and-pin system. The EMV system is used to secure over two billion credit and debit cards world-wide. We also looked at various protocols used by Barclays Bank to secure millions of euros worth of transactions per day.

Finally, the expertise developed in the project enabled the PI to found the start-up Dyadic Security, with Prof. Yehuda Lindell from Bar-Ilan University (another ERC grantee).