الفهرس 
AbstractOnly 14 pages are availabe for public view
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Abstract
Cryptography is probably the most important aspect of communications security and is becoming increasingly important as a basic building block for computer security. It uses the mathematical techniques for the secure transmission of a private message over an insecure channel. An important kind of private data is the biomedical images. The rapid growth and widespread use of electronic data processing fueled the need for better methods of protecting store, process and transmit this critical data information. A wide range applications are rapidly developed in field that interconnect things, internet of things (IoT) become an imperative required trend by industries and academicians. IoT become a base infrastructure for remotely access or control depending on internet protocol (IP) networks specially after covid-19 pandemic. The huge application domains’ infrastructure that depends on IoT, requires a trusted connection to guarantee a security and privacy while transferring data. This thesis proposes a hybrid identity authentication pipeline that integrates three schemes. Namely, an elliptic curve cryptography (ECC) scheme is integrated with Ong, Schnorr, and Shamir (OSS) signature scheme and chaotic maps. The latter satisfies both security and guarantee criteria. The novelty of the proposal is appeared in using chaotic mapping and cyclic group to deduce a substitution box (S-Box) and a reversible matrix as a portion of the OSS signature equation. The ECC-based security part is an efficient public key cryptography mechanism with less computational cost that makes it the most convenient to be used in IoT devices for authentication and privacy. The strength of the proposed scheme relies on combining discrete logarithm problem (DLP) and integer factorization problem (IFP). The proposed approach has been simulated using Lab-View and has been compared with other state-of-the art schemes. Extensive simulation results and analysis of the security and time rendering results confirmed its durability against different types of attacks, such as linear and differential attacks. After that A novel encoding method for elliptic curve cryptosystem is proposed to provide high security level and is more efficient and complexity if compared with the traditional public key cryptosystems. The proposed method encodes data and key selection over prime field. Compared with traditional ECC algorithm, the proposed encoding scheme proved its robustness based on some statistical analyzes. Correlation Coefficient (CC), Entropy, Peak Signal to Noise Ratio (PSNR), Number of changing pixel rate (NPCR), and Unified Average Changing Intensity (UACI) are used to quantify ciphertext strength and securing performance on gray and colored image to measure how much robustness is the proposed encoding technique. Together with the encryption scheme, a Least Significant Bit (LSB) steganography technique is subjoined after encryption process to hide the ciphertext. Overall results of the previews metrics were satisfied and its recommended to use the proposed encoding method with the ECC.