The Analysis of Galois Substitution Counter Mode (GSCM)

In~\cite{gscm}, GSCM mode of operation for authenticated encryption was presented. GSCM is based on the Galois/Counter Mode (GCM). GSCM is an enhancement of GCM, which is characterized by its high throughput and low memory consumption in network applications. In this paper, we propose some enhancements to GSCM and compare it with the different implementations of GCM. We present stability, performance, memory and security analyses of different implementations of GSCM and GCM

Extended Substitution Cipher Chaining mode (ESCC)

In this paper, we present a new tweakable narrow-block mode of operation, the Extended Substitution Cipher Chaining mode (ESCC), that can be efficiently deployed in disk encryption applications. ESCC is an extention of Substitution Cipher Chaining mode (SCC)~\cite{scc}. Unlike SCC, ESCC is resistant to the attacks in~\cite{scc_attack,scc_attack2}

Cryptanalysis of Substitution Cipher Chaining Mode (SCC)

In this paper, we present an enhanced cryptanalysis of the Substitution Cipher Chaining mode (SCC)~\cite{scc}. In~\cite{scc_attack}, SCC-128 (SCC which uses AES with 128-bit key) was broken using 5 attacks, where the authors used an active attack model (where the attacker can force the disk encryption application to re-encrypt a sector for her), the complexity of these attacks are at most 2$^{40}$ cipher executions. In this paper, we enhance the main attack on SCC-128, this enhancement decrease the complexity of SCC-128 attacks to be at most 2$^{14}$ cipher executions. We also cryptanalze SCC-128 in a less restrictive attack model, our attacks are upper bounded with 2$^{40}$ cipher executions

Statistical Testing for Disk Encryption Modes of Operations

In this paper we present a group of statistical tests that explore the random behavior of encryption modes of operations, when used in disk encryption applications. The results of these tests help us to better understand how these modes work. We tested ten modes of operations with the presented statistical tests, five of the narrow-block type and the other five of the wide-block type. Our analysis shows some weakness in some of these modes. Keywords: Disk encryption, modes of operations, randomness, AES

Grades eines genehmigten Dissertation.

am 22.10.2009 angenommen. Preface The research presented in this thesis has been carried out at the Institute for Data Processing (LDV) at Technische Universität München (TUM). This was during my stay as a DAAD (Deutscher Akademischer Austausch Dienst) scholarship holder. Throughout this period, I had the opportunity to meet and collaborate with several persons who have contributed to its accomplishment. First of all, I am deeply thankful to Prof.Dr.-Ing. Klaus Diepold for his great care, valuable advices, helpful guidance, and providing the di erent facilities to carry out this work. He was always a frequent source of support and guidance in all aspects and at all times. I am deeply thankful to Prof. Dr. Claudia Eckert for the interest she showed to co-advise my work. I deeply appreciate DAAD who have granted me the scholarship. Furthermore I am deeply thankful to my colleagues at LDV that have provided the environment for sharing their experiences about the problems involved. Finally I want to thank my family and my friends. The encouragement and support from them is a powerful source of inspiration and energy. A special thought is devoted to my parents for never-ending support