International Association
for Cryptologic Research

It is not known how to design cryptographic algorithms that remain secure if the attacker has also access to the intermediate results. Therefore, the current research concentrates on implementation techniques that ensure that the intermediate results of the cryptographic algorithm are statistically independent of the secret key.

A new method to construct provably secure against side-channel attacks implementations (called Threshold Implementation) has been proposed by researchers from COSIC. The approach is based on secret sharing and multi-party computation methods. Proof-of-concept implementations have been proposed already for several ciphers including Present and AES.

We can prove security against attacks that are based on correlating a secret variable to the expected values of the power consumption or any other side-channel of a device.

Research

Currently, we are investigating how we can achieve security against more advanced attacks. The research combines mathematical methods and insights with statistical methods and circuit design techniques. We are also interested to learn how our approach will be affected by the use of future technologies, which can further scale down cost and power while allowing more signal processing complexity.

The student will research issues related to one or more of the following work-packages:

1. Extending the mathematical framework of the Threshold Implementation approach,

2. Assessing real-life effects that occur in modern CMOS technologies, when countermeasures are applied,

3. Determining the overhead introduced by our protection measures and to evaluate its cost and effectiveness by doing experiments in an emerging technology.