Simple power attack (SPA) is a type of side-channel attack (SCA). In the literature, many SPA-resistant scalar multiplication algorithms have been proposed, but most are inefficient and not interoperable with other coding methods. To prevent SPA, Chevallier-Mames et al. proposed a technique called side-channel atomicity for pure binary number systems. Using their method, extra costs for preventing SPA can be limited. Even though many researchers have extended this technique to other number systems, their algorithms are for specific cases and few provide implementation results. In this paper, we generalize the atomicity technique to protect nearly all existing fast coding methods/number systems. Our general framework provides security and flexibility while its efficiency is coupled to that of the coding methods. Moreover, we utilize our framework to protect the known fastest scalar multiplications by exploring application on the GLV method for GLS curves. Proof of concept programs are written in the C language along with assembly for fast field operations and run on AMD Athlon X2 245-based hardware.

Many researchers monitor malicious software (malware) behavior using Virtual Machines (VM) to protect the underlying operating system. For virtual machines, the malware monitor process exists at the same layer as the real system so the monitor can get detailed behavior information without being discovered. There are some Anti-VM techniques employed by malware authors to ward off collection, analysis and reverse engineering of their malicious programs. Therefore, malware researchers may obtain inaccurate analysis from VM aware programs. This paper presents a solution to detect Anti-VM techniques. We collect behavioral information from malware and use an enhanced behavior distance algorithm to calculate the difference between real and virtual environments to distinguish if the malware has Anti-VM capability. Our experiments show this algorithm works well. This idea can improve malware analysis results and reduce malware misdetection.

Abstract Establishing trust relationships between peers is an essential approach to prevent threats. Most current approaches concentrate on polling algorithms to evaluate peer trustworthiness, but these approaches are either system‐expensive or inefficient. In this paper, we propose a concrete challenge‐based trust protocol for P2P networks. Our protocol uses challenge‐response operations in each trust evaluation phase and validates every contacted peer along with recording their corresponding trust value. The scheme in our protocol utilizes random selection of challenges, and does not reveal additional information, so malicious peers have little opportunity to tamper with the P2P systems. Simulation results show our protocol saves communication cost by around 90%. We suggest a tolerance value of 0.2 which gives a design reference for implementing new P2P trust‐establishing protocols. Copyright © 2010 John Wiley & Sons, Ltd.

The term digital rights management (DRM) generally refers to a set of policies and techniques that guide the proper use of digital content. Due to the nature of digital content, it is easily modified and distributed. DRM is already progressive in many industries and has received a fair amount of attention in recent years. To prevent multimedia content from being usurped, there is much research which focuses on how to build a reliable DRM system. In this paper, we propose a DRM model to provide improvements for several existing research issues. We use a "ticket" to achieve anonymous consumption and design a protocol to protect against malicious servers. A solution is proposed which addresses these issues and brings more functionality to users.

In this paper, a key pre-distribution model with the concept of key pool generation in distributed sensor networks (DSNs) is proposed. In this scheme, additional information is inserted into each group during key pool generation. The nodes in the DSNs can use this extra information to increase system performance. A concrete example is given to clarify this concept and prove that the added information in the scheme can greatly improve connectivity between nodes even if node deployment is sparse or non-uniform. In addition, high connectivity decreases the energy consumption of wireless communication between sensor nodes and extends the life of these nodes.

With the incoming of information era, web-based service has been developed rapidly and offered more and more business. These “open”, and widely “web enabled” applications are subject to greater and greater levels and types of attacks as hackers exploit vulnerabilities within the software like SQL Injection and Cross Site Scripts (XSS) attack. In this paper, we proposed a type of novel Embedded Markov Model (EMM) to detect different web application attacks, monitor the on-line user behavior and defend the malevolent user promptly. Comparing to previous web application attacks detecting approaches, our EMM approach can not only detect user’s invalidated input errors but also find out the unreasonable page transition behavior. By detecting unreasonable page transition, we can immediately defend the malevolent or silly user behavior to avoid the further web system failures and sensitive information disclosure. Furthermore, we implement an on-line user behavior surveillance system and use the real web traffic to evaluate the performance of our system. The experiment results show that our proposed EMM method can discover the abnormal behavior of malevolent user and detect the invalidated input attacks like SQL injection, XSS and string buffer overflow attacks.

According to a study from Gartner Group [13], mostly successful attacks exploit software applications and operating systems that were not properly configured or vulnerability patched. Regarding enterprises, there are far reaching consequences if their online services are attacked and compromised. As a result, making their systems safer is becoming a higher priority. In this paper, we proposed a system to resolve the vulnerability and misconfiguration issues. In the vulnerability part, we focus on the aspect of vulnerability assessment. We use CVSS (Common Vulnerability Scoring System) to measure the vulnerability severity to the organization and help administrators with patch management. For the configuration portion, we use CCE (Common Configuration Enumeration) configuration scanner to scan the system and determine the presence of the misconfiguration in the system. The experiments show that our system can help administrators to understand their own systems and enhance system security.

The conditional access system (CAS) is an essential part of digital pay-TV systems for controlling access to the program services. Conventionally, due to the restrictions of bandwidth and computational capability, a CAS only supports period subscription services that are charged on a monthly basis. In this paper, based on the concept of hierarchical key assignment, we propose three key distribution schemes for the access control of pay-TV systems. With these schemes, a CAS can support more charging strategies for service providers, such as adopting a smaller charging unit and allowing a subscription of any subset of channels with little communication and computational overhead. In addition, the piracy management problem can also be dealt with easily.

We propose a new strategy to improve the performance of multicomputations, such as computing xA + yB in an additive group or axbyin a multiplicative group. This new strategy is called asynchronous strategy. In each iteration, it tries to compute partial results by pairing nearby zero and nonzero bits. The new strategy can be applied to any binary code of x and y to further reduce the computational cost. However, our experiments show that sparse signed-digit code can achieve minimum computational cost. The algorithms using the asynchronous strategy need only O(h) extra registers when they try to do computation with bits which are h positions apart

Conventional hierarchical key assignment schemes have not been concerned with a practical situation: Users might be assigned to a class for only a period of time. When a user leaves a class, the keys of that class and all the descendent classes must be renewed. For applications where the privileges of users change frequently or where there are many users, the communication load for key redistributions is very large. Recently, Tzeng (2002) proposed a time-bound hierarchical key assignment scheme to address this issue. However, Tzeng's scheme was very complex and suffered from a collusion attack. In this paper, we propose an efficient time-bound scheme based on a technique called merging. The idea behind merging is to consider primitive keys instead of hierarchies. It is conceptually like the compression used in source coding. Through this technique, it is feasible to combine multiple keys into an aggregate key. Thus, communication and storage requirements are greatly reduced. This technique can also be used for an alternative implementation of Akl-Taylor's scheme. Moreover, it can be used to construct a systematic approach for adjusting hierarchies in Akl-Taylor's scheme as well. Through the insights gained from these exercises, we may see that some problems that are usually addressed by the conventional key assignment schemes can be solved directly via merging, with better performance. Furthermore, if other suitable merging functions are found in the future, new secure hierarchical key assignment schemes and time-bound schemes is obtained accordingly.

In the past 20 years, DES has been the most widely used symmetric block cipher for information security. Recently, a novel method called Differential Fault Analysis (DFA) has been proposed to attack DES. Under the assumption that the attacker can induce errors into the cipher device, the key of DES can be unveiled easily. The assumed technique is not mature today, but is like to appear in the near future, especially for attacking a tamper resistant device with an embedded DES VLSI chip. In this paper, we proposed a new hardware design for the DES cipher to resist DFA. By adding some protection circuitry, all the unidirectional faults induced into the registers of a DES chip can be detected, and then alter to the cryptosystem immediately. A hardware emulation experiment using Altera's CPLD chip shows the effectiveness of the protection design.

A common method for constructing t-error correcting/all unidirectional error detecting (t-EC/AUED) codes is to append a tail to t-EC code, where the tail is a function of the weight of the codeword. Here, we present a method to reduce the weight distribution of t-EC codes by using a DC/sub m/(k+d, k) code as the input of t-EC code where a DC/sub m/(k+d, k) code is of length k+dnd 2/sup k/ codewords with the weight distribution between [(k+d-m)/2] and [(k+d+m)/2]. It is shown that our t-EC/AUED codes have the better information rates than the previously developed codes due to the smaller tails.

The Key Escrow System (KES) bridges the gap between users' privacy and social needs for protection against criminal behavior. However, there are some disadvantages and controversies regarding the system. In this paper, we propose a new key escrow system, which not only meets the requirements of the KES but also provides a key recovery feature for users. The system can be implemented easily in software or hardware with familiar and tested public cryptographic functions that should significantly reduce controversy.

C.H. Lin et al. (1995) proposed a new public-key cipher system whose security is based upon the Diophantine equations. In this note, we show that their scheme is insecure under the ciphertext only attack.

An efficient algorithm to count the cardinalities of certain subsets of constant weight binary vectors is presented in this paper. The algorithm enables us to design I-symmetric error correcting/all unidirectional error detecting (1-syEC/AUED) codes with the highest cardinality based on the group Z/sub n/. Since a field Z/sub p/ is a group, this algorithm can also be used to design a field 1-syEC/AUED code. We can construct t-syEC/AUED codes for f=2 or 3 by appending a tail to the field 1-syEC/AUED codes. The information rates of the proposed t-syEC/AUED codes are shown to be better than the previously developed codes.

A digital signature algorithm is developed which is an improved version of the digital signature algorithm (DSA) proposed by the NIST (1991). The security of the improved version is the same as the original one while it benefits the signature signer and performs more efficiently.>

In this paper, an improved digital signature is developed based on the famous Schnorr (1990) or Brickell-McCurley (1991) schemes. It is shown that both the new scheme and the previous two originals rely on the same security assumptions. The novel feature of this proposed signature is that it can be verified in a batch manner and the improved efficiency is approximately proportional to the number of signatures to be verified.>

A design methodology for conference-key distribution systems (CKDSs) that is based on the threshold scheme for broadcasting networks is proposed. It is shown that if a conference chairman can share a secret key with each of the other conference participants, then any threshold scheme can be used to construct a CKDS. Since there already exist many identification (ID)-based key distribution systems for two users sharing a common secret key, ID-based CKDSs can easily be constructed for broadcasting networks.>

A password authentication mechanism based on the public-key distribution cryptosystem is proposed. The scheme uses an authentication table to replace the traditional password file. With this scheme, even if the authentication table is comprised, the system security is preserved. The user's password is effectively bound to the user's identification in a timely, efficient, and simple manner.>

A novel ID-based cryptographic scheme for implementing a public-key cryptosystem and signature is proposed. Instead of generating and publishing a public key for each user, the ID-based scheme permits each user to choose his/her name or network address as his/her public key. This eliminates the needs of a large public field and the exchange of private or public keys. The major advantage of the ID-based cryptosystem based on this scheme over other published ID-based cryptosystems is that the number of users can be extended to t*L users without degrading the system's security even when users conspire, where L is the number of the system's secrets, and t is the number of factors in p-1, where p is a large prime number.>

Two algorithms are proposed to improve the Merkle-Hellman knapsack public-key cryptosystem. an approach to transform a superincreasing sequence to a high-density knapsack sequence is proposed. The algorithm is easy to implement and eliminates the redundancy of many knapsack cryptosystems. A linear shift method is used to improve the security of the knapsack public-key cryptosystem. It is shown that several knapsacks (e.g., the so-called useless knapsack), which cannot be generated by using the Merkle-Hellman scheme, can be generated by the linear shift method. Thus A. Shamir's (1982, 1984) attack to the original knapsack, as well as the low-density attack to the iterated knapsack, cannot be applied to this system successfully. It is interesting to note that the concept of the requirement of being one-to-one in practical enciphering keys is not necessary for this system.>

A single-key-lock (SKL) mechanism used for implementing the access matrix of a computer protection system is proposed. The key selection is very flexible. The lock values are generated recursively using the Newton interpolating polynomial. A new user/file can be inserted into the system without recomputing all locks/keys. Since the computational load of the key-lock operation depends on the key positions in the access matrix, a user-hierarchy structure can be constructed for the mechanism. Thus, the smallest key value is assigned to a user who accesses the information resources more frequently than others, in order to reduce the average computation time. An example is included to illustrate this idea.>