Biblio

Covert communications, where a transmitter Alice wishes to hide the presence of her transmitted signal from a watchful adversary Willie, has been considered extensively in recent years. Those investigations have generally considered physical-layer models, where the adversary has access to a sophisticated (often optimal) receiver to determine whether a transmission has taken place, and have addressed the question of what rate can information be communicated covertly. More recent investigations have begun to consider the change in covert rate when Willie has uncertainty about the physical layer environment. Here, we move up the protocol stack to consider the covert rate when Willie is watching the medium-access control (MAC) layer in a network employing a random access MAC such as slotted ALOHA. Based on the rate of collisions and potentially the number of users involved in those collisions, Willie attempts to determine whether unauthorized (covert) users are accessing the channel. In particular, we assume different levels of sophistication in Willie's receiver, ranging from a receiver that only can detect whether there was a collision or not, to one that can always tell exactly how many packets were on the channel in the random access system. In each case, we derive closed-form expressions for the achievable covert rates in the system. The achievable rates exhibit significantly different behavior than that observed in the study of covert systems at the physical layer.

Information or data is a very crucial resource. Hence securing the information becomes a critical task. Transfer and Communication mediums via which we send this information do not provide data security natively. Therefore, methods for data security have to be devised to protect the information from third party and unauthorized users. Information hiding strategies like steganography provide techniques for data encryption so that the unauthorized users cannot read it. This work is aimed at creating a novel method of Augmented Reality Steganography (ARSteg). ARSteg uses cloud for image and key storage that does not alter any attributes of an image such as size and colour scheme. Unlike, traditional algorithms such as Least Significant Bit (LSB) which changes the attributes of images, our approach uses well established encryption algorithm such as Advanced Encryption Standard (AES) for encryption and decryption. This system is further secured by many alternative means such as honey potting, tracking and heuristic intrusion detection that ensure that the transmitted messages are completely secure and no intrusions are allowed. The intrusions are prevented by detecting them immediately and neutralizing them.

Cloud computing is a standard architecture for providing computing services among servers and cloud user (CU) for preserving data from unauthorized users. Therefore, the user authentication is more reliable to ensure cloud services accessed only by a genuine user. To improve the authentication accuracy, Tiger Hash-based Kerberos Biometric Blowfish Authentication (TH-KBBA) Mechanism is introduced for accessing data from server. It comprises three steps, namely Registration, Authentication and Ticket Granting. In the Registration process, client enrolls user details and stores on cloud server (CS) using tiger hashing function. User ID and password is given by CS after registration. When client wants to access data from CS, authentication server (AS) verifies user identity by sending a message. When authenticity is verified, AS accepts user as authenticated user and convinces CS that user is authentic. For convincing process, AS generates a ticket and encrypted using Blowfish encryption. Encrypted ticket is sent back to user. Then, CU sends message to server containing users ID and encrypted ticket. Finally, the server decrypts ticket using blowfish decryption and verifies the user ID. If these two ID gets matched, the CS grants requested data to the user. Experimental evaluation of TH-KBBA mechanism and existing methods are carried out with different factors such as Authentication accuracy, authentications time and confidentiality rate with respect to a number of CUs and data.

The objective of the Honeypot security system is a mechanism to identify the unauthorized users and intruders in the network. The enterprise level security can be possible via high scalability. The whole theme behind this research is an Intrusion Detection System and Intrusion Prevention system factors accomplished through honeypot and honey trap methodology. Dynamic Configuration of honey pot is the milestone for this mechanism. Eight different methodologies were deployed to catch the Intruders who utilizing the unsecured network through the unused IP address. The method adapted here to identify and trap through honeypot mechanism activity. The result obtained is, intruders find difficulty in gaining information from the network, which helps a lot of the industries. Honeypot can utilize the real OS and partially through high interaction and low interaction respectively. The research work concludes the network activity and traffic can also be tracked through honeypot. This provides added security to the secured network. Detection, prevention and response are the categories available, and moreover, it detects and confuses the hackers.

Recent years have witnessed the trend of increasingly relying on distributed infrastructures. This increased the number of reported incidents of security breaches compromising users' privacy, where third parties massively collect, process and manage users' personal data. Towards these security and privacy challenges, we combine hierarchical identity based cryptographic mechanisms with emerging blockchain infrastructures and propose a blockchain-based data usage auditing architecture ensuring availability and accountability in a privacy-preserving fashion. Our approach relies on the use of auditable contracts deployed in blockchain infrastructures. Thus, it offers transparent and controlled data access, sharing and processing, so that unauthorized users or untrusted servers cannot process data without client's authorization. Moreover, based on cryptographic mechanisms, our solution preserves privacy of data owners and ensures secrecy for shared data with multiple service providers. It also provides auditing authorities with tamper-proof evidences for data usage compliance.