This paper describes an innovative method of the power analysis which presents the typical example of successful attacks against trusted cryptographic devices such as RFID (Radio-Frequency IDentification) and contact smart cards. The proposed method analyzes power consumption of the AES (Advanced Encryption Standard) algorithm with a neural network, which successively classifies the first byte of the secret key. This way of the power analysis is an entirely new approach and it is designed to combine the advantages of simple and differential power analysis. In the extreme case, this feature allows to determine the whole secret key of a cryptographic module only from one measured power trace. This attribute makes the proposed method very attractive for potential attackers. Besides theoretical design of the method, we also provide the first implementation results. We assume that the method will be certainly optimized to obtain more accurate classification results in the future.

Innovative Method of the Power Analysis

Power analysis observes the power consumption of cryptographic device depending on its activity and following attack uses the measured power traces to determine some sensitive information to abuse the device. Differential power analysis attacks are the most popular because the attacker does not need detailed knowledge about the attacked device but on the other hand, these attacks use mathematical approach and power consumption models. Understanding and the subsequent realization of the whole attack is not an easy task by no means. Therefore, this article describes the general schema on which all analyses are based on and best known statistical test including the basic power simulation models. We realized the best known power analysis based on correlation coefficient with a detailed description of the individual steps and we adjusted the general schema for this concrete example for better understanding of the attack. After reading the article, the reader is well familiarized about any context of the complex problems of differential power analysis.

General scheme of differential power analysis

http://www.scielo.org.mx/pdf/jart/v13n1/v13n1a2.pdf

Privacy-preserving security solution for cloud services

In this paper, we present a novel privacy-preserving security solution for cloud services. We deal with user anonymous access to cloud services and shared storage servers. Our solution provides registered users with anonymous access to cloud services. Our solution offers anonymous authentication. This means that users' personal attributes (age, valid registration, successful payment) can be proven without revealing users' identity. Thus, users can use services without any threat of profiling their behavior. On the other hand, if users break provider's rules, their access rights are revoked. We analyze current privacy preserving solutions for cloud services and outline our solution based on advanced cryptographic components. Our solution offers anonymous access, unlinkability and the confidentiality of transmitted data. Moreover, we implement our solution and we output the experimental results and compare the performance with related solutions.

Efficient security solution for privacy-preserving cloud services

The article describes the main principle and methods of simple electromagnetic analysis and thus provides an overview of simple electromagnetic analysis. The introductions chapters describe specific SPA attack used visual inspection of EM traces, template based attack and collision attack. After reading the article, the reader is sufficiently informed of any context of SEMA. Another aim of the article is the practical realization of SEMA which is focused on AES implementation. The visual inspection of EM trace of AES is performed step by step and the result is the determination of secret key Hamming weight. On the resulting EM trace, the Hamming weight of the secret key 1 to 8 was clearly visible. This method allows reduction from the number of possible keys for following brute force attack.

/pdf/simple-electromagnetic-analysis-in-cryptography-5bckprprs0.pdf

Simple Electromagnetic Analysis in Cryptography

The article describes the optimization of differential side channel analysis which is often used in differential power analysis. The introductory chapters discusses in great detail the theoretical background of method. The new improvement is proposed, which allow reduction of the required calculations by 73% and it is in the worst case. The method is based on knowledge of the Hamming weight of secret key. Hamming weight of secret key can be determined by adding only one reference measurement of power consumption. The testbed focused on measuring direct emissions was built to verify proposal optimization and experimental verification was carried out.

Tomas Macha

Papers

Optimization of differential power analysis