Dealing with security requirements in fixed budgets and strict time limits is becoming increasingly complex, time-consuming, and resource-intensive. In addition, the system becomes more complicated when protecting the replicated distributed real-time database system (RDRTDBS) under many security guidelines. Vital structures, military, government, and financial institutions face immense pressure to secure their databases from unauthorized access. Such specifications mandate a rigorous security scan of each device before they are deemed appropriate for use. In the current paper, we demonstrate that performance and security requirements can be achieved simultaneously. We introduce PASS, a performance-aware security-satisfied replication protocol for data replica sites. Our proposed solution (i.e., PASS) is heuristic rather than optimal. Our main concept is to minimize the number of encryption operations for the least important or rarely accessed data items. PASS reduces the number of encryption operations by categorizing data items into three categories: (i) most secure, (ii) medium secure, and (iii) least secure. The most secure and medium secure data items are protected by the key generated from our proposed algorithm and the existing algorithm, respectively. In contrast, the Least Secure data items are kept unencrypted, and no encryption operation is performed to secure such data items. Effectively minimizing encryption operations implies a reduction in computation and power consumption at data replica sites. Unlike traditional encrypted RDRTDBS that stores data encryption keys on disks and encrypts all data items, we present a hybrid key generation method that encrypts only the important data items. Based on the experimental results, we conclude that PASS reduces the number of encryption operations and provides high-level protection in RDRTDBS.

The Internet of Vehicle enables million of vehicles to transfer sensitive information through an Internet of Things assisted networking system. It is a very challenging idea wherein different types of data authentication protocols have been designed number theory based assumptions (RSA/DLP). The quantum computers are big threats to number theoretic assumptions. In this article, we have designed a post quantum secure aggregate signature assisted data authentication framework for internet of vehicles. Further, a secure aggregate signature assisted data authentication framework have been proposed that supports batch data verification. We have proposed an efficient aggregate signature to verify authenticity of multiple vehicles in one step. The security of protocol relies upon two assumptions, (1) Module Learning With Errors and (2) Module Short Integer Solution. The proposed design ensures security against quantum attacks. The design is simulated in ns3 to capture latency and throughput, respectively.

Dependency relationship plays an essential role in coordinating and processing the real time transactions (RTTs) in the replicated distributed real time database systems (RDRTDBS). These dependency relationships can be represented as commit dependency, abort dependency, serial dependency, terminate dependency, exclusion dependency etc. Creation of an incorrect dependency relationship can result in performance degradation in terms of loss of data integrity and also non-availability of RDRTDBS. Therefore, in this paper, different types of dependency relationships have been enumerated among executing RTTs in the RDRTDBS. These relationships have been coordinated by using the concept of working set holding the relevant association between RTTs and used for the scheduling of resources for the execution of the RTTs based on the users’ demand of consistency criteria, i.e., replica consistency, temporal consistency, and timeliness. Our experimental results significantly show that coordinating dependency relationships and processing of transaction on the basis of these appropriate measures improve the replica consistency, temporal consistency, and timeliness of the RDRTDBS.

Replicated distributed real time database system (RDRTDBS) is widely used in various real time applications such as financial services, travel/aviation systems, government services, autopilot systems, etc. These real time applications require ceaseless assistance from the back-end database 24 × 7. However, it is not practical to avoid all kinds of failure in the RDRTDBS. The conventional recovery algorithms prevent the processing of admitted real time transactions (RTTs) during recovery of the recovering failed site. Our objective is to propose the recovery algorithm that simultaneously allows the processing of admitted RTTs and recovery of recovering failed replica site. In the current paper, middleware has been proposed for recovering the abandoned replica site and synchronising the consistency among replica sites. The recovery is conducted explicitly by the feedback sublayer, which consists of four algorithms: status collector, suspect confirmer, recovery algorithm and log updater. These proposed algorithms collaboratively work to identify and recover the recovering site from system failure. Quantitative evaluation of our proposed algorithms indicates that our proposed algorithms shall be more effective and efficient than traditional fault recovery techniques.

Replication techniques have drawn a great deal of appeal in the real-time database system (RTDBS). In this technique, the replication protocol (RPCL) has been studied as one of the primary technologies. Existing RPCL causes improper resource utilization and suffers from large communication costs. Hence, the objective is to propose a solution that effectively utilizes the system resource and decreases the large communication cost. The proposed data mining algorithm identifies the frequently accessed data items, their related data access sequence, and replicate those data items on the demanded replica sites. Additionally, mutual consistency among newly created data replica and existing data replica gets satisfied with the proposed RPCL. The experimental result shows that the proposed solutions improve the performance of the system by reducing the issue of unnecessary replica updation, unnecessary storage utilization, and unnecessary bandwidth utilization.

Replication protocol (RPCL) has been the major focused area for research in the replicated distributed real-time database system (RDRTDBS). The primary objective of RPCL is to improve the availability, scalability, and fault tolerance of the system. However, the most challenging task is to guarantee QoS for the data services in the RDRTDBS. The real-time transaction workload may not be balanced, and their access patterns may be time-varying and skewed. As a result, many RTTs miss their deadlines, or consistency constraints of the real-time data items may be violated. In the current paper, our objective is to propose an integrated version of a transaction manager that consists of the transaction sub-module and granule sub-module, thread to granule policy, and overload resolver (OLRE) to guarantee quality of service (QoS) during unpredictable workload. The experimental results show that our proposed algorithms reduce the overload condition and improve the processing of real-time transactions (RTTs) with maintaining mutual consistency.

In a distributed real time database system (DRTDBS), replication technique is used to easily meet the timeliness demand of real time transactions. The features of replication technique depend on the Replication Protocols (RPLs). Existing RPLs are kernel-based which is tightly linked with the concurrency control protocol and confined to a vendor-specific database. Middleware is the evolution of the kernel-based RPL that shifts the load of maintaining mutual consistency from the database kernel to the middleware server. Middleware based RPLs suffer from the issue of QoS, security-constraint, and dependency relationship. Here, our objective is to maintain the QoS during overload occurrence in the replicated DRTDBS (RDRTDBS). The proposed framework in this paper consists of a system model for expressing QoS requirements, a middleware extended with the prediction technique to predict the RTT processing time, and a set of policies to guarantee QoS. The performance of our proposed algorithms is compared with other baseline approaches and simulation results show that it outperforms a set of existing algorithms that use feedback control to overcome overload.

The demand for scalability in replicated distributed real-time database systems (RDRTDBS) is still explorative and, despite an increase in real-time applications, many challenges and issues remain in designing a more scalable system. The objective is to improve the scalability of the system during system scale up with new replica sites. Existing research has been mainly conducted in maintaining replica consistency between different replicas via replication protocol. However, very little research has been conducted towards improving scalability and maintaining mutual consistency and timeliness. Consequently, the ultimate aim of this chapter is to improve scalability in RDRTDBS such that performance of the system does not degrade even though new replica sites are added.

Security in replicated distributed real time database system (RDRTDBS) is still explorative and, despite an increase in real-time applications, many issues and challenges remain in designing a more secure system model. However, very little research has been reported for maintaining security, timeliness, and mutual consistency. This chapter proposes the secure system model for RDRTDBS which secures the system from malicious attack. To prevent the request/response from malicious attack, authors have extended the system model with a cryptographic algorithm. In the cryptographic algorithm, a key must be secretly known only to the sender and receiver. Thus, in this chapter, authors have used the key generation algorithm to generate a key using an image. This secure system model maintains the confidentiality of the replicated data item and preserves its data integrity. It performs better in terms of malicious attack compared to other non-secure system models.

Real time transaction (RTT) management poses a new challenge in the design of replicated distributed real time database system (RDRTDBS). Existing replication protocols maintain only the mutual consistency between replicated data objects and lack to support the RTT management. This paper explores different scenarios of interaction between coordinator, cohorts & updaters and proposes measures to be taken for each scenario such that performances of the system get improved and at the same time mutual consistency can also be maintained. Additionally, a strict consistency criterion has also been followed to prevent the user from accessing the inconsistent value. This proposed work increases performance in terms of availability, scalability and reliability with respect to other replication protocols.

Replication is the technique to provide the opportunity of deadline fulfillment of real-time transaction in distributed real-time database system (DRTDBS). Just-in-time real-time replication (JITRTR), on-demand real-time replication (ORDER), on-demand real-time replication with replica sharing (ORDER-RS), periodic transactions using partial replication (PTUDPR), periodicity prediction algorithm, and so on are the replication protocols designed for DRTDBS. None of the algorithms follow one-copy serializability (1SR) correctness criteria for real-time and non-real-time data items. Our main objective is to fulfill strict consistency together with transaction deadline fulfillment. In this paper, the proposed model works on multi-master together with slave sites and uses middleware for following 1SR correctness criteria. In the proposed model, master sites are responsible for executing update and write transactions and slave sides are responsible for executing only read transaction. The proposed model performs better in terms of deadline fulfillment and strict consistency with respect to other replication protocol.

The replicated distributed real-time database system (RDRTDBS) has gained great interest in providing highly available and scalable services. This technique provides the additional benefits of performance in terms of availability, fault-tolerance and reliability. These desired performance metrics are achieved via proper adaptation of replica update technique (RUT). In this paper, our aim is to discuss the stateof-art of RUTs, issues & current development, proposed approach & its significance and directions for future research

Efficient replication protocols are required to satisfy the stringent requirement of mutual consistency and timeliness for replicated distributed real-time database system (RDRTDBS). Existing protocol such as distributed two-phase locking (D2PL) is well suited for providing strict correctness but suffers from long blocking delays, priority inversion, deadlock and lack of consideration of timing constraint. These issues cause many real-time transactions (RTTs) to miss their deadline. The main goal is to improve transaction miss ratio (TMR) for admitted RTTs. This paper proposes the concept of the dynamic version of the data object which will create the multiple versions of the data object as per admitted RTTs and finally converge to a single value following one copy serializability (1SR) correctness criteria. Additionally, it is also proposed to broadcast the admitted RTT during the locking phase of D2PL, so that, decentralized decision for commit or abort can be taken independently. The proposed concept of the dynamic version of the data object performs better as compared to existing concepts of dual version or multi-version data object.

The design and implementation of replicated distributed real time database system (RDRTDBS) must meet two rigorous requirements; deadline of real time transactions (RTTs) and preserving of the mutual consistency of replicated data. Previous researches in RDRTDBS have been concentrated mainly on designing of replica update techniques (RUTs) for soft and firm RTTs with sole correctness criteria of serializability and epsilon serializability. No work has been reported for predictable processing of real time transaction (RTT) with guaranteeing the mutual consistency of replicated data. Therefore, this paper first addresses the factors of predictability and mutual consistency in RDRTDBS and then briefly discusses the features and requirements of RDRTDBS and presents a processing plan that supports predictable execution of hard, soft and firm RTT along with maintaining the mutual consistency. The simulation results demonstrate that the proposed processing scheme enhances the performance of RDRTDBS beyond that offered by the existing RUTs.

Cryptography is basically securing the data during the communication between different systems. To provide the security of data during communication in cryptography we together require the Algorithm and Key. The confidentiality and integrity of the data during communication depends partially on algorithm and partially on key. Due to human memorizability the size of key in cryptography is limited. 2Dimension graphics image have the property that by visualising or by listening its dimension it is not possible to design exactly the same pattern. In this paper a modified approach is being proposed for increasing the security of the data. For increasing the security we are basically concentrating on the key part of the cryptography we basically uses the 2Dimension graphics image which is designed by the user. 2Dimension Graphics image is composed of pixels in which each pixel have different or same ASCII value. From the large collection of pixel the proposed algorithm will generate any size of key which can be used in encryption as well as in decryption.