Trust Evaluation for Embedded Systems Security research challenges identified from an incident network scenario

This paper is about trust establishment and trust evaluations techniques. A short background about trust, trusted computing and security in embedded systems is given. An analysis has been done of an incident network scenario with roaming users and a set of basic security needs has been identified. These needs have been used to derive security requirements for devices and systems, supporting the considered scenario. Using the requirements, a list of major security challenges for future research regarding trust establishment in dynamic networks have been collected and elaboration on some different approaches for future research has been done.This work was supported by the Knowledge foundation and RISE within the ARIES project

Linköping Studies in Science and Technology Dissertation No. 722 Codes for Digital

To my great pleasure Unlicensed, or illegal, copying of data is a problem in many areas. Despite various efforts in copy protection and copyright enforcement (both legal and technical), the problem still exists, and with the growing use of digital means of storing and distributing data the problem seems to be getting worse. Storing a unique, invisible marking in each distributed object is a possible way of dealing with the problem of illegal copying. That way, if an illegal copy is found somewhere, it is possible to find the original holder of the object and to take legal action. This type of copyright enforcement scheme is called fingerprinting. This thesis deals with codes for fingerprinting of digital data in the context of several users colluding to create an untraceable, illegal copy (such users are called pirates). Some theoretical bounds on the performance of such codes are presented. A general method to statistically test whether certain users have taken part in the creation of a particular illegal copy is presented, and pirate strategies that prevent this kind of testing are derived. A simple testing method is presented that tests whether a certain, proposed group of users should be considered guilty of having created a specific illegal fingerprint. The method’s performance is analysed, and it is found that the error probability is practical for an interesting range of values of the number of colluding pirates and the length of the fingerprints. The set of possible pirate strategies is derived and a compact representation is presented. It is shown that the fingerprinting problem is a general game theoretical problem. Finally, a combinatorial performance measure for binary fingerprinting codes is presented, and several code constructions are analysed using this measure. i i

Random Codes for Digital Fingerprinting

Unlicensed, or illegal, copying of data is a problem in many areas. Despite various efforts in copy protection and copyright enforcement (both legal and technical), the problem still exists, and with the growing use of digital means of storing and distributing data the problem seems to be getting worse

CODING CIRCUITS FOR REDUCING HAMMING WEIGHT

Using a newly introduced alternative to a conventional SRAM cell a binary zero can be written with a much lower power consumption than a binary one. Such a solution reduces power consumption, especially if there are few ones in the data, that is, if the data has a low Hamming weight. If the data is not inherently of low weight, this can be achieved by encoding the data. In the paper such coding is discussed and in small cases energy efficient encoding and decoding realizations are presented. 1

Non-Redundant Coding for Deep Sub-Micron Address Buses

A coding technique for deep sub-micron address buses with inter-wire capacitances dominating the wire-to-ground capacitances is presented. This code is similar to Gray codes, in the sense that it defines an ordering of the binary space, such that adjacent codewords dissipate little energy when sent consecutively. The ordering is shown to be close to optimal, as to the energy dissipation, when sending the whole sequence in order. A circuit diagram realizing the coder is presented, using only  ¢¡¤ £ two-input gates, where is the bus width. Simulations show an improvement in energy dissipation of more than 50 % over an uncoded bus in several cases, depending on the data being coded