Active Coating

Project Description

This research project is funded by Österreichische Nationalbank (OeNB) and investigates the coating of chips used in smartcards. Here is an outline of the project' intentions:

Smartcards are commonly accepted as the major physical link between persons and their electronic identity. Currently we see the emergence of powerful systems on smartcards which also can generate and verify digital signatures on-chip. Today’s silicon technology and knowledge about smart implementations of cryptographical algorithms makes this feasible. With these systems it is no longer necessary to trust the card reader system which typically is unknown to the owner of the card.

If smartcards should be used as tokens for protecting values against misuse, their strength against attacks is of crucial importance. This becomes evident if one considers their expected volumes and reflects their vulnerability due to their non-observability when being distributed in high quantities. The system on the smartcard should ideally be unbreakable in terms of cryptography, and should be able to identify its lawful owner. In other words: it should be able to protect its secret under any kind of attack, be it electrically, physically, and/or mechanically. And it should incorporate biometrical methods in order to be able to recognize its owner.

The major component for a general solution for achieving this goal is the use of cryptography. The mathematical background of this field has been studied by the academic community for 20 to 30 years and is¾ although still heavily evolving¾ well understood. Algorithms and protocols for achieving concepts like mutual authentication etc. are also known and accepted. Efficient implementations of these algorithms in software are available, and knowledge about the mechanics of these is meanwhile taught in many university courses.

Only recently also details about hardware implementations of these algorithms have been published and studied by the research community. Most knowledge about implementation details of security related hardware is still kept secretly in companies. The design of systems on silicon, where cryptographical functions are incorporated in order to hide data, asks for a new mix of techniques and design methods. In addition to traditional parameters like power consumption, area, and clock speed, security issues need to be taken into account. Developer and customer of such systems also need to develop a new relationship in order to establish enough trust about the reported security of the system.

We also face new ways of getting hold of secret keys stored in a hardware device, even without having to know the internal organisation of the device, like differential cryptanalysis.

The art of physical protection of a chip against some attack is still in its infancy, and is currently probably the weakest point of the typical overall smartcard system. Reading out values from a smartcard’s memory has been reported to be very easy given the knowhow of how to do this. With the expected broad distribution of smartcards this knowhow will most likely also spread, and misuses will happen more often.

The main idea of the project is to cover the silicon device with an "active coating material". This material visually hides the chip and its properties are used by the hidden system to detect any change of this coating. This idea is new and a patent submitted by the project leader is pending.