Browsing by Author "Dr. Tariq Javed Zia"

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    Implementation of Multivariate Public Key Cryptosystem on Digital Signature Scheme
    (Library Information Services COMSATS University Lahore Campus, 2024-03-17) Leeza Raza; SP23-RMT-014; Dr. Tariq Javed Zia; LHR TP 9567
    Due to the increase in exchange of secret information in todays digital world robust cryptographic systems have been designed to guarantee secure transmission. The world of cryptographic security is transforming continually, however this is considerably at risk due to quantum computers. Cryptosystem based on multivariable equations have been considered resilient against quantum attacks can be a basis of a post-quantum secure communication system. Some important types of this algorithm which are unique in structure and promising in security are oil-vinegar scheme and its types and Rainbow scheme. “Jacques Patarin” introduced Oil-Vinegar scheme” in 1997. This is a digital signature scheme based on solving the multivariate quadratic polynomials over a finite field. This system relies on the structural and balanced oil and vinegar variables which guarantee security, nonlinearity, and efficiency. Depending on the choice of variables, there exist two types of the “oil-vinegar scheme” namely; “Balanced Oil-Vinegar scheme” and Unbalanced Oil-Vinegar scheme (UOV). There is another important digital signature scheme named Rainbow Signature Scheme.
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    Using Cryptography and Steganography Techniques for Data Security
    (Library Information Services, COMSATS University Islamabad, Lahore Campus, 2025) Umm e Amara; CIIT/FA23-RMT-041/LHR; Dr. Tariq Javed Zia; LHR TP 10064
    This thesis explores a hybrid security framework that integrates cryptographic and stegano- graphic techniques to enhance data security in digital communication. The proposed model combines the RSA encryption algorithm with XOR ciphering and Least Significant Bit (LSB) image steganography. To secure the data, it is first encrypted with both RSA and XOR operations. The resulting ciphertext is then hidden in a digital image by modifying the LSB’s of the image’s pixel data. The analysis focuses on three critical metrics: the amount of data that can be hidden (embedding capacity), the resulting fidelity of the carrier image (image quality), and the processing resources required (computational complexity). Experimental results demonstrate that 1-bit and 2-bit LSB methods provide an optimal balance between security, imperceptibility, and processing efficiency, while deeper em- bedding increases data capacity at the cost of visible distortion and higher computational overhead. Evaluation metrics such as PSNR, MSE, BER, and correlation analysis con- firm the effectiveness of the hybrid approach in securing data transmission with minimal perceptual degradation. The findings highlight the potential of combining cryptography and steganography for robust, multi-layered protection of sensitive information in modern communication systems.