Biblio

The QR codes have gained wide popularity in mobile marketing and advertising campaigns. However, the hidden security threat on the involved information system might endanger QR codes' success, and this issue has not been adequately addressed. In this paper we propose to examine the life cycle of a redesigned QR code ecosystem to identify the possible security risks. On top of this examination, we further propose standard changes to enhance security through a digital signature mechanism.

Public Key Regime (PKR) was proposed as an alternative to certificate based PKI in securing Vehicular Networks (VNs). It eliminates the need for vehicles to append their certificate for verification because the Road Side Units (RSUs) serve as Delegated Trusted Authorities (DTAs) to issue up-to-date public keys to vehicles for communications. If a vehicle's private/public key needs to be revoked, the root TA performs real time updates and disseminates the changes to these RSUs in the network. Therefore, PKR does not need to maintain a huge Certificate Revocation List (CRL), avoids complex certificate verification process and minimizes the high latency. However, the PKR scheme is vulnerable to Denial of Service (DoS) and collusion attacks. In this paper, we study these attacks and propose a pre-authentication mechanism to secure the PKR scheme. Our new scheme is called the Secure Public Key Regime (SPKR). It is based on the Schnorr signature scheme that requires vehicles to expend some amount of CPU resources before RSUs issue the requested public keys to them. This helps to alleviate the risk of DoS attacks. Furthermore, our scheme is secure against collusion attacks. Through numerical analysis, we show that SPKR has a lower authentication delay compared with the Elliptic Curve Digital Signature (ECDSA) scheme and other ECDSA based counterparts.

The ExFAT file system is for large capacity flash memory medium. On the base of analyzing the characteristics of ExFAT file system, this paper presents a model of electronic data recovery forensics and judicial Identification based on ExFAT. The proposed model aims at different destroyed situation of data recovery medium. It uses the file location algorithm, file character code algorithm, document fragment reassembly algorithm for accurate, efficient recovery of electronic data for forensics and judicial Identification. The model implements the digital multi-signature, process monitoring, media mirror and Hash authentication in the data recovery process to improve the acceptability, weight of evidence and Legal effect of the electronic data in the lawsuit. The experimental results show that the model has good work efficiency based on accuracy.

The Center for Strategic and International Studies estimates the annual cost from cyber crime to be more than \$400 billion. Most notable is the recent digital identity thefts that compromised millions of accounts. These attacks emphasize the security problems of using clonable static information. One possible solution is the use of a physical device known as a Physically Unclonable Function (PUF). PUFs can be used to create encryption keys, generate random numbers, or authenticate devices. While the concept shows promise, current PUF implementations are inherently problematic: inconsistent behavior, expensive, susceptible to modeling attacks, and permanent. Therefore, we propose a new solution by which an unclonable, dynamic digital identity is created between two communication endpoints such as mobile devices. This Physically Unclonable Digital ID (PUDID) is created by injecting a data scrambling PUF device at the data origin point that corresponds to a unique and matching descrambler/hardware authentication at the receiving end. This device is designed using macroscopic, intentional anomalies, making them inexpensive to produce. PUDID is resistant to cryptanalysis due to the separation of the challenge response pair and a series of hash functions. PUDID is also unique in that by combining the PUF device identity with a dynamic human identity, we can create true two-factor authentication. We also propose an alternative solution that eliminates the need for a PUF mechanism altogether by combining tamper resistant capabilities with a series of hash functions. This tamper resistant device, referred to as a Quasi-PUDID (Q-PUDID), modifies input data, using a black-box mechanism, in an unpredictable way. By mimicking PUF attributes, Q-PUDID is able to avoid traditional PUF challenges thereby providing high-performing physical identity assurance with or without a low performing PUF mechanism. Three different application scenarios with mobile devices for PUDID and Q-PUDI- have been analyzed to show their unique advantages over traditional PUFs and outline the potential for placement in a host of applications.

Advanced Persistent Threat (APT), unlike traditional hacking attempts, carries out specific attacks on a specific target to illegally collect information and data from it. These targeted attacks use special-crafted malware and infrequent activity to avoid detection, so that hackers can retain control over target systems unnoticed for long periods of time. In order to detect these stealthy activities, a large-volume of traffic data generated in a period of time has to be analyzed. We proposed a scalable solution, Ctracer to detect stealthy command and control channel in a large-volume of traffic data. APT uses multiple command and control (C&C) channel and change them frequently to avoid detection, but there are common signatures in those C&C sessions. By identifying common network signature, Ctracer is able to group the C&C sessions. Therefore, we can detect an APT and all the C&C session used in an APT attack. The Ctracer is evaluated in a large enterprise for four months, twenty C&C servers, three APT attacks are reported. After investigated by the enterprise's Security Operations Center (SOC), the forensic report shows that there is specific enterprise targeted APT cases and not ever discovered for over 120 days.

A frequent claim that has not been validated is that signature based network intrusion detection systems (SNIDS) cannot detect zero-day attacks. This paper studies this property by testing 356 severe attacks on the SNIDS Snort, configured with an old official rule set. Of these attacks, 183 attacks are zero-days' to the rule set and 173 attacks are theoretically known to it. The results from the study show that Snort clearly is able to detect zero-days' (a mean of 17% detection). The detection rate is however on overall greater for theoretically known attacks (a mean of 54% detection). The paper then investigates how the zero-days' are detected, how prone the corresponding signatures are to false alarms, and how easily they can be evaded. Analyses of these aspects suggest that a conservative estimate on zero-day detection by Snort is 8.2%.

Hashing algorithms are used extensively in information security and digital forensics applications. This paper presents an efficient parallel algorithm hash computation. It's a modification of the SHA-1 algorithm for faster parallel implementation in applications such as the digital signature and data preservation in digital forensics. The algorithm implements recursive hash to break the chain dependencies of the standard hash function. We discuss the theoretical foundation for the work including the collision probability and the performance implications. The algorithm is implemented using the OpenMP API and experiments performed using machines with multicore processors. The results show a performance gain by more than a factor of 3 when running on the 8-core configuration of the machine.

In any security system, there are many security issues that are related to either the sender or the receiver of the message. Quantum computing has proven to be a plausible approach to solving many security issues such as eavesdropping, replay attack and man-in-the-middle attack. In the e-voting system, one of these issues has been solved, namely, the integrity of the data (ballot). In this paper, we propose a scheme that solves the problem of repudiation that could occur when the voter denies the value of the ballot either for cheating purposes or for a real change in the value by a third party. By using an entanglement concept between two parties randomly, the person who is going to verify the ballots will create the entangled state and keep it in a database to use it in the future for the purpose of the non-repudiation of any of these two voters.

Critical Infrastructure represents the basic facilities, services and installations necessary for functioning of a community, such as water, power lines, transportation, or communication systems. Any act or practice that causes a real-time Critical Infrastructure System to impair its normal function and performance will have debilitating impact on security and economy, with direct implication on the society. SCADA (Supervisory Control and Data Acquisition) system is a control system which is widely used in Critical Infrastructure System to monitor and control industrial processes autonomously. As SCADA architecture relies on computers, networks, applications and programmable controllers, it is more vulnerable to security threats/attacks. Traditional SCADA communication protocols such as IEC 60870, DNP3, IEC 61850, or Modbus did not provide any security services. Newer standards such as IEC 62351 and AGA-12 offer security features to handle the attacks on SCADA system. However there are performance issues with the cryptographic solutions of these specifications when applied to SCADA systems. This research is aimed at improving the performance of SCADA security standards by employing NTRU, a faster and light-weight NTRU public key algorithm for providing end-to-end security.

Cloud computing is one of the emerging computing technology where costs are directly proportional to usage and demand. The advantages of this technology are the reasons of security and privacy problems. The data belongs to the users are stored in some cloud servers which is not under their own control. So the cloud services are required to authenticate the user. In general, most of the cloud authentication algorithms do not provide anonymity of the users. The cloud provider can track the users easily. The privacy and authenticity are two critical issues of cloud security. In this paper, we propose a secure anonymous authentication method for cloud services using identity based group signature which allows the cloud users to prove that they have privilege to access the data without revealing their identities.

Skype has been a typical choice for providing VoIP service nowadays and is well-known for its broad range of features, including voice-calls, instant messaging, file transfer and video conferencing, etc. Considering its wide application, from the viewpoint of ISPs, it is essential to identify Skype flows and thus optimize network performance and forecast future needs. However, in general, a host is likely to run multiple network applications simultaneously, which makes it much harder to classify each and every Skype flow from mixed traffic exactly. Especially, current techniques usually focus on host-level identification and do not have the ability to identify Skype traffic at the flow-level. In this paper, we first reveal the unique sequence signatures of Skype UDP flows and then implement a practical online system named SkyTracer for precise Skype traffic identification. To the best of our knowledge, this is the first time to utilize the strong sequence signatures to carry out early identification of Skype traffic. The experimental results show that SkyTracer can achieve very high accuracy at fine-grained level in identifying Skype traffic.

Recently, cloud computing has been spotlighted as a new paradigm of database management system. In this environment, databases are outsourced and deployed on a service provider in order to reduce cost for data storage and maintenance. However, the service provider might be untrusted so that the two issues of data security, including data confidentiality and query result integrity, become major concerns for users. Existing bucket-based data authentication methods have problem that the original spatial data distribution can be disclosed from data authentication index due to the unsophisticated data grouping strategies. In addition, the transmission overhead of verification object is high. In this paper, we propose a privacy-aware query authentication which guarantees data confidentiality and query result integrity for users. A periodic function-based data grouping scheme is designed to privately partition a spatial database into small groups for generating a signature of each group. The group signature is used to check the correctness and completeness of outsourced data when answering a range query to users. Through performance evaluation, it is shown that proposed method outperforms the existing method in terms of range query processing time up to 3 times.

The modular exponentiation is an important operation for cryptographic transformations in public key cryptosystems like the Rivest, Shamir and Adleman, the Difie and Hellman and the ElGamal schemes. computing ax mod n and axby mod n for very large x,y and n are fundamental to the efficiency of almost all pubic key cryptosystems and digital signature schemes. To achieve high level of security, the word length in the modular exponentiations should be significantly large. The performance of public key cryptography is primarily determined by the implementation efficiency of the modular multiplication and exponentiation. As the words are usually large, and in order to optimize the time taken by these operations, it is essential to minimize the number of modular multiplications. In this paper we are presenting efficient algorithms for computing ax mod n and axbymod n. In this work we propose four algorithms to evaluate modular exponentiation. Bit forwarding (BFW) algorithms to compute ax mod n, and to compute axby mod n two algorithms namely Substitute and reward (SRW), Store and forward(SFW) are proposed. All the proposed algorithms are efficient in terms of time and at the same time demands only minimal additional space to store the pre-computed values. These algorithms are suitable for devices with low computational power and limited storage.
 

The strong development of the Internet of Things (IoT) is dramatically changing traditional perceptions of the current Internet towards an integrated vision of smart objects interacting with each other. While in recent years many technological challenges have already been solved through the extension and adaptation of wireless technologies, security and privacy still remain as the main barriers for the IoT deployment on a broad scale. In this emerging paradigm, typical scenarios manage particularly sensitive data, and any leakage of information could severely damage the privacy of users. This paper provides a concise description of some of the major challenges related to these areas that still need to be overcome in the coming years for a full acceptance of all IoT stakeholders involved. In addition, we propose a distributed capability-based access control mechanism which is built on public key cryptography in order to cope with some of these challenges. Specifically, our solution is based on the design of a lightweight token used for access to CoAP Resources, and an optimized implementation of the Elliptic Curve Digital Signature Algorithm (ECDSA) inside the smart object. The results obtained from our experiments demonstrate the feasibility of the proposal and show promising in order to cover more complex scenarios in the future, as well as its application in specific IoT use cases.

As most of the modern encryption algorithms are broken fully/partially, the world of information security looks in new directions to protect the data it transmits. The concept of using DNA computing in the fields of cryptography has been identified as a possible technology that may bring forward a new hope for hybrid and unbreakable algorithms. Currently, several DNA computing algorithms are proposed for cryptography, cryptanalysis and steganography problems, and they are proven to be very powerful in these areas. This paper gives an architectural framework for encryption & Generation of digital signature using DNA Cryptography. To analyze the performance; the original plaintext size and the key size; together with the encryption and decryption time are examined also the experiments on plaintext with different contents are performed to test the robustness of the program.

Hashing algorithms are used extensively in information security and digital forensics applications. This paper presents an efficient parallel algorithm hash computation. It's a modification of the SHA-1 algorithm for faster parallel implementation in applications such as the digital signature and data preservation in digital forensics. The algorithm implements recursive hash to break the chain dependencies of the standard hash function. We discuss the theoretical foundation for the work including the collision probability and the performance implications. The algorithm is implemented using the OpenMP API and experiments performed using machines with multicore processors. The results show a performance gain by more than a factor of 3 when running on the 8-core configuration of the machine.
 

Signcryption is a cryptographic primitive that simultaneously realizes both the functions of public key encryption and digital signature in a logically single step, and with a cost significantly lower than that required by the traditional “signature and encryption” approach. Recently, an efficient certificateless signcryption scheme without using bilinear pairings was proposed by Zhu et al., which is claimed secure based on the assumptions that the compute Diffie-Hellman problem and the discrete logarithm problem are difficult. Although some security arguments were provided to show the scheme is secure, in this paper, we find that the signcryption construction due to Zhu et al. is not as secure as claimed. Specifically, we describe an adversary that can break the IND-CCA2 security of the scheme without any Unsigncryption query. Moreover, we demonstrate that the scheme is insecure against key replacement attack by describing a concrete attack approach.
 

In large-scale systems, user authentication usually needs the assistance from a remote central authentication server via networks. The authentication service however could be slow or unavailable due to natural disasters or various cyber attacks on communication channels. This has raised serious concerns in systems which need robust authentication in emergency situations. The contribution of this paper is two-fold. In a slow connection situation, we present a secure generic multi-factor authentication protocol to speed up the whole authentication process. Compared with another generic protocol in the literature, the new proposal provides the same function with significant improvements in computation and communication. Another authentication mechanism, which we name stand-alone authentication, can authenticate users when the connection to the central server is down. We investigate several issues in stand-alone authentication and show how to add it on multi-factor authentication protocols in an efficient and generic way.

Web applications need to validate and sanitize user inputs in order to avoid attacks such as Cross Site Scripting (XSS) and SQL Injection. Writing string manipulation code for input validation and sanitization is an error-prone process leading to many vulnerabilities in real-world web applications. Automata-based static string analysis techniques can be used to automatically compute vulnerability signatures (represented as automata) that characterize all the inputs that can exploit a vulnerability. However, there are several factors that limit the applicability of static string analysis techniques in general: 1) undesirability of static string analysis requires the use of approximations leading to false positives, 2) static string analysis tools do not handle all string operations, 3) dynamic nature of the scripting languages makes static analysis difficult. In this paper, we show that vulnerability signatures computed for deliberately insecure web applications (developed for demonstrating different types of vulnerabilities) can be used to generate test cases for other applications. Given a vulnerability signature represented as an automaton, we present algorithms for test case generation based on state, transition, and path coverage. These automatically generated test cases can be used to test applications that are not analyzable statically, and to discover attack strings that demonstrate how the vulnerabilities can be exploited.
 

In 2013, Biswas and Misic proposed a new privacy-preserving authentication scheme for WAVE-based vehicular ad hoc networks (VANETs), claiming that they used a variant of the Elliptic Curve Digital Signature Algorithm (ECDSA). However, our study has discovered that the authentication scheme proposed by them is vulnerable to a private key reveal attack. Any malicious receiving vehicle who receives a valid signature from a legal signing vehicle can gain access to the signing vehicle private key from the learned valid signature. Hence, the authentication scheme proposed by Biswas and Misic is insecure. We thus propose an improved version to overcome this weakness. The proposed improved scheme also supports identity revocation and trace. Based on this security property, the CA and a receiving entity (RSU or OBU) can check whether a received signature has been generated by a revoked vehicle. Security analysis is also conducted to evaluate the security strength of the proposed authentication scheme.

Recently, cloud computing has been spotlighted as a new paradigm of database management system. In this environment, databases are outsourced and deployed on a service provider in order to reduce cost for data storage and maintenance. However, the service provider might be untrusted so that the two issues of data security, including data confidentiality and query result integrity, become major concerns for users. Existing bucket-based data authentication methods have problem that the original spatial data distribution can be disclosed from data authentication index due to the unsophisticated data grouping strategies. In addition, the transmission overhead of verification object is high. In this paper, we propose a privacy-aware query authentication which guarantees data confidentiality and query result integrity for users. A periodic function-based data grouping scheme is designed to privately partition a spatial database into small groups for generating a signature of each group. The group signature is used to check the correctness and completeness of outsourced data when answering a range query to users. Through performance evaluation, it is shown that proposed method outperforms the existing method in terms of range query processing time up to 3 times.

Cloud computing is a new paradigm and emerged technology for hosting and delivering resources over a network such as internet by using concepts of virtualization, processing power and storage. However, many challenging issues are still unclear in cloud-based environments and decrease the rate of reliability and efficiency for service providers and users. User Authentication is one of the most challenging issues in cloud-based environments and according to this issue this paper proposes an efficient user authentication model that involves both of defined phases during registration and accessing processes. Geo Detection and Digital Signature Authorization (GD2SA) is a user authentication tool for provisional access permission in cloud computing environments. The main aim of GD2SA is to compare the location of an un-registered device with the location of the user by using his belonging devices (e.g. smart phone). In addition, this authentication algorithm uses the digital signature of account owner to verify the identity of applicant. This model has been evaluated in this paper according to three main parameters: efficiency, scalability, and security. In overall, the theoretical analysis of the proposed model showed that it can increase the rate of efficiency and reliability in cloud computing as an emerging technology.

In this paper, we present an open cloud DRM service provider to protect the digital content's copyright. The proposed architecture enables the service providers to use an on-the fly DRM technique with digital signature and symmetric-key encryption. Unlike other similar works, our system does not keep the encrypted digital content but lets the content creators do so in their own cloud storage. Moreover, the key used for symmetric encryption are managed in an extremely secure way by means of the key fission engine and the key fusion engine. The ideas behind the two engines are taken from the works in secure network coding and secret sharing. Although the use of secret sharing and secure network coding for the storage of digital content is proposed in some other works, this paper is the first one employing those ideas only for key management while letting the content be stored in the owner's cloud storage. In addition, we implement an Android SDK for e-Book readers to be compatible with our proposed open cloud DRM service provider. The experimental results demonstrate that our proposal is feasible for the real e-Book market, especially for individual businesses.

In this paper, we have proposed the IBE-RAOLSR and ECDSA-RAOLSR protocols for WMNs (Wireless Mesh Networks), which contributes to security routing protocols. We have implemented the IBE (Identity Based Encryption) and ECDSA (Elliptic Curve Digital Signature Algorithm) methods to secure messages in RAOLSR (Radio Aware Optimized Link State Routing), namely TC (Topology Control) and Hello messages. We then compare the ECDSA-based RAOLSR with IBE-based RAOLSR protocols. This study shows the great benefits of the IBE technique in securing RAOLSR protocol for WMNs. Through extensive ns-3 (Network Simulator-3) simulations, results have shown that the IBE-RAOLSR outperforms the ECDSA-RAOLSR in terms of overhead and delay. Simulation results show that the utilize of the IBE-based RAOLSR provides a greater level of security with light overhead.

Certificateless public key cryptography (CL-PKC) combines the advantage of both traditional PKC and identity-based cryptography (IBC) as it eliminates the certificate management problem in traditional PKC and resolves the key escrow problem in IBC. Recently, Choi et al. and Tso et al.proposed two different efficient CL short signature schemes and claimed that the two schemes are secure against super adversaries and satisfy the strongest security. In this study, the authors show that both Choi et al.'s scheme and Tso et al.'s scheme are insecure against the strong adversaries who can replace users' public keys and have access to the signing oracle under the replaced public keys.