Abstract:
The protection of personal information is of utmost significance in today’s digitally connected
society. In this digital era, encryption is seen as a rapidly developing trend. Despite
the development of sophisticated modern information security techniques, storage, and
retrieval procedures, the internet’s widespread use, unsecured transmission channels, and
hacking tools continue to pose significant issues. To address the issue of privacy and data security,
several techniques have been developed, yet there is still need of developing efficient
and secure cryptosystem for images/videos.
In this thesis, several time efficient and secure image encryption techniques are proposed for
different applications. We propose a hybrid chaotic map which is a combination of two 1-D
chaotic maps, i.e Gauss and Square. These two maps have simple structures, however, by
combining these nonlinear chaotic maps results in highly complex and unpredictable chaotic
map. Using this chaotic map, we further propose an efficient chaos-based encryption technique
for images/videos. The chaos based image encryption technique employs chaotic map
proposed above in scrambling and substitution steps to encrypt images providing high security.
Chaos-based algorithms are useful as they provide images with high security and
suitable for encrypting images in real-time applications. Proposed image encryption also
provides security in content based image retrieval by efficiently retrieving similar images in
encrypted domain. One of the prime utility of this technique may be seen in maintaining
privacy of health records of patients on cloud server. This thesis also explores selective encryption
technique in which only some part of the image is important and needs complex
encryption algorithm to provide high end security. Then a framework is proposed for remote
monitoring of vital signs by integrating digital twins technology to enable real-time
monitoring with minimal cost overhead. To secure the data stored in third party cloud, all
the mathematical computations are performed on encrypted data. We have also proposed a
trusted federated learning approach for applications where all the data (in the form of images)
can not be stored in central location due to some privacy or legal restrictions. By
introducing trust and security in federated learning, activities of malicious users are minimized
which leads to more accurately trained model. The proposed techniques are evaluated
using various security measures and results are compared with the state of art existing technique
to verify the significance of proposed image encryption technique. Simulation results
demonstrate that all the proposed techniques exhibit efficiency and produce highly secured
images.