Secure Message Recovery and Batch Verification using Digital Signature

This paper about the study of Secure message Recovery and batch verification using Digital Signature Security is increased in batch verification through triple DES algorithm Encryption is used for the Security in which the plaintext is transforming into the cipher text A digital signature scheme involves two phases the signature generation phase which is performed at the sender side and the signature verification phase that is performed by the receiver of that message In computer to computer communication the computer at sender s end usually transforms a plaintext into cipher text using encryption When the message is recovered at the Receiver Side than the original text is converted in to the encrypted text That encrypted text is secure for the authenticated person After recover the message if authentic person wants to get the original text then he she enter the key and take the plaintex

Hide The Modulus: A Secure Non-Interactive Fully Verifiable Delegation Scheme for Modular Exponentiations via CRT

Security protocols using public-key cryptography often requires large number of costly modular exponentiations (MEs). With the proliferation of resource-constrained (mobile) devices and advancements in cloud computing, delegation of such expensive computations to powerful server providers has gained lots of attention. In this paper, we address the problem of verifiably secure delegation of MEs using two servers, where at most one of which is assumed to be malicious (the OMTUP-model). We first show verifiability issues of two recent schemes: We show that a scheme from IndoCrypt 2016 does not offer full verifiability, and that a scheme for $n$ simultaneous MEs from AsiaCCS 2016 is verifiable only with a probability $0.5909$ instead of the author\u27s claim with a probability $0.9955$ for $n=10$. Then, we propose the first non-interactive fully verifiable secure delegation scheme by hiding the modulus via Chinese Remainder Theorem (CRT). Our scheme improves also the computational efficiency of the previous schemes considerably. Hence, we provide a lightweight delegation enabling weak clients to securely and verifiably delegate MEs without any expensive local computation (neither online nor offline). The proposed scheme is highly useful for devices having (a) only ultra-lightweight memory, and (b) limited computational power (e.g. sensor nodes, RFID tags)

Hierarchical Group Based Mutual Authentication and Key Agreement for Machine Type Communication in LTE and Future 5G Networks

In view of the exponential growth in the volume of wireless data communication among heterogeneous devices ranging from smart phones to tiny sensors across a wide range of applications, 3GPP LTE-A has standardized Machine Type Communication (MTC) which allows communication between entities without any human intervention. The future 5G cellular networks also envisage massive deployment of MTC Devices (MTCDs) which will increase the total number of connected devices hundredfold. This poses a huge challenge to the traditional cellular system processes, especially the traditional Mutual Authentication and Key Agreement (AKA) mechanism currently used in LTE systems, as the signaling load caused by the increasingly large number of devices may have an adverse effect on the regular Human to Human (H2H) traffic. A solution in the literature has been the use of group based architecture which, while addressing the authentication traffic, has their share of issues. This paper introduces Hierarchical Group based Mutual Authentication and Key Agreement (HGMAKA) protocol to address those issues and also enables the small cell heterogeneous architecture in line with 5G networks to support MTC services. The aggregate Message Authentication Code based approach has been shown to be lightweight and significantly efficient in terms of resource usage compared to the existing protocols, while being robust to authentication message failures, and scalable to heterogeneous network architectures

Privacy-Preserving Protocols for Vehicular Transport Systems

La present tesi es centra en la privadesa dels ciutadans com a usuaris de mitjans de transport vehiculars dins del marc d'una e-society. En concret, les contribucions de la tesi es focalitzen en les subcategories d'estacionament de vehicles privats en zones públiques regulades i en la realització de transbordaments entre línies intercomunicades en l'àmbit del transport públic. Una anàlisi acurada de les dades recopilades pels proveedors d'aquests serveis, sobre un determinat usuari, pot proporcionar informació personal sensible com per exemple: horari laboral, professió, hobbies, problemes de salut, tendències polítiques, inclinacions sexuals, etc. Tot i que existeixin lleis, com l'europea GDPR, que obliguin a utilitzar les dades recollides de forma correcta per part dels proveedors de serveis, ja sigui a causa d'un atac informàtic o per una filtració interna, aquestes dades poden ser utilitzades per finalitats il·legals. Per tant, el disseny protocols que garanteixin la privadesa dels ciutadans que formen part d'una e-society esdevé una tasca de gran importància.La presente tesis se centra en la privacidad de los ciudadanos en el transporte vehicular dentro del marco de una e-society. En concreto, las contribuciones de la tesis se centran en las subcategorías de estacionamiento de vehículos privados en zonas públicas reguladas y en la realización de transbordos entre líneas interconectadas en el ámbito del transporte público. Una análisi acurada de los datos recopilados por los proveedores de los servicios, sobre un determinado usuario, puede proporcionar información personal sensible como por ejemplo: horario laboral, profesión, hobbies, problemas de salud, tendencias políticas, inclinaciones sexuales, etc. A pesar que hay leyes, como la europea GDPR, que obligan a usar de forma correcta los datos recopilados por parte de los proveedores de servicios, ya sea por un ataque informático o por una filtración interna, estos datos pueden utilizarse para fines ilegales. Por lo tanto, es vital diseñar protocolos que garanticen la privacidad de los ciudadanos que forman parte de una e-society.This thesis is focused on the privacy of citizens while using vehicular transport systems within an e-society frame. Specifically, the thesis contributes to two subcategories. The first one refers to pay-by-phone systems for parking vehicles in regulated public areas. The second one is about the use of e-tickets in public transport systems allowing transfers between connecting lines. A careful analysis of data collected by service providers can provide sensitive personal information such as: work schedule, profession, hobbies, health problems, political tendencies, sexual inclinations, etc. Although the law, like the European GDPR, requires the correct use of the data collected by service providers, data can be used for illegal purposes after being stolen as a result of a cyber-attack or after being leaked by an internal dishonest employee. Therefore, the design of privacy-preserving solutions for mobility-based services is mandatory in the e-society

CONSTRUCTION OF EFFICIENT AUTHENTICATION SCHEMES USING TRAPDOOR HASH FUNCTIONS

In large-scale distributed systems, where adversarial attacks can have widespread impact, authentication provides protection from threats involving impersonation of entities and tampering of data. Practical solutions to authentication problems in distributed systems must meet specific constraints of the target system, and provide a reasonable balance between security and cost. The goal of this dissertation is to address the problem of building practical and efficient authentication mechanisms to secure distributed applications. This dissertation presents techniques to construct efficient digital signature schemes using trapdoor hash functions for various distributed applications. Trapdoor hash functions are collision-resistant hash functions associated with a secret trapdoor key that allows the key-holder to find collisions between hashes of different messages. The main contributions of this dissertation are as follows: 1. A common problem with conventional trapdoor hash functions is that revealing a collision producing message pair allows an entity to compute additional collisions without knowledge of the trapdoor key. To overcome this problem, we design an efficient trapdoor hash function that prevents all entities except the trapdoor key-holder from computing collisions regardless of whether collision producing message pairs are revealed by the key-holder. 2. We design a technique to construct efficient proxy signatures using trapdoor hash functions to authenticate and authorize agents acting on behalf of users in agent-based computing systems. Our technique provides agent authentication, assurance of agreement between delegator and agent, security without relying on secure communication channels and control over an agent’s capabilities. 3. We develop a trapdoor hash-based signature amortization technique for authenticating real-time, delay-sensitive streams. Our technique provides independent verifiability of blocks comprising a stream, minimizes sender-side and receiver-side delays, minimizes communication overhead, and avoids transmission of redundant information. 4. We demonstrate the practical efficacy of our trapdoor hash-based techniques for signature amortization and proxy signature construction by presenting discrete log-based instantiations of the generic techniques that are efficient to compute, and produce short signatures. Our detailed performance analyses demonstrate that the proposed schemes outperform existing schemes in computation cost and signature size. We also present proofs for security of the proposed discrete-log based instantiations against forgery attacks under the discrete-log assumption

Secure and Privacy-Preserving Vehicular Communications

Road safety has been drawing increasing attention in the public, and has been subject to extensive efforts from both industry and academia in mitigating the impact of traffic accidents. Recent advances in wireless technology promise new approaches to facilitating road safety and traffic management, where each vehicle (or referred to as On-board unit (OBU)) is allowed to communicate with each other as well as with Roadside units (RSUs), which are located in some critical sections of the road, such as a traffic light, an intersection, and a stop sign. With the OBUs and RSUs, a self-organized network, called Vehicular Ad Hoc Network (VANET), can thus be formed. Unfortunately, VANETs have faced various security threats and privacy concerns, which would jeopardize the public safety and become the main barrier to the acceptance of such a new technology. Hence, addressing security and privacy issues is a prerequisite for a market-ready VANET. Although many studies have recently addressed a significant amount of efforts in solving the related problems, few of the studies has taken the scalability issues into consideration. When the traffic density is getting large, a vehicle may become unable to verify the authenticity of the messages sent by its neighbors in a timely manner, which may result in message loss so that public safety may be at risk. Communication overhead is another issue that has not been well addressed in previously reported studies. Many efforts have been made in recent years in achieving efficient broadcast source authentication and data integrity by using fast symmetric cryptography. However, the dynamic nature of VANETs makes it very challenging in the applicability of these symmetric cryptography-based protocols. In this research, we propose a novel Secure and Efficient RSU-aided Privacy Preservation Protocol, called SERP^3, in order to achieve efficient secure and privacy-preserving Inter-Vehicle Communications (IVCs). With the commitments of one-way key chains distributed to vehicles by RSUs, a vehicle can effectively authenticate any received message from vehicles nearby even in the presence of frequent change of its neighborship. Compared with previously reported public key infrastructure (PKI)-based packet authentication protocols for security and privacy, the proposed protocol not only retains the security and privacy preservation properties, but also has less packet loss ratio and lower communication overhead, especially when the road traffic is heavy. Therefore, the protocol solves the scalability and communication overhead issues, while maintaining acceptable packet latency. However, RSU may not exist in some situations, for example, in the early stage deployment phase of VANET, where unfortunately, SERP^3 is not suitable. Thus, we propose a complementary Efficient and Cooperative Message Validation Protocol, called ECMVP, where each vehicle probabilistically validates a certain percentage of its received messages based on its own computing capacity and then reports any invalid messages detected by it. Since the ultimate goal of designing VANET is to develop vehicle safety/non-safety related applications to improve road safety and facilitate traffic management, two vehicle applications are further proposed in the research to exploit the advantages of vehicular communications. First, a novel vehicle safety application for achieving a secure road traffic control system in VANETs is developed. The proposed application helps circumvent vehicles safely and securely through the areas in any abnormal situation, such as a car crash scene, while ensuring the security and privacy of the drivers from various threats. It not only enhances traveler safety but also minimizes capacity restrictions due to any unusual situation. Second, the dissertation investigates a novel mobile payment system for highway toll collection by way of vehicular communications, which addresses all the issues in the currently existing toll collection technologies