| dc.description.abstract | The onset of the pandemic made companies go digital; this led to massive
data transfer hence the need for highly secure and fast data encryption
techniques. Most real-time applications in mobile communication, military,
and private organizations often require safe and reliable data monitoring and
transfer. As one of the most crucial areas of information security, chaos based image encryption has attracted academics and scientists over the past
few years. Several studies with different approaches and new algorithms to
make image encryption systems safer were proposed in recent studies.
Traditional encryption techniques are challenging to understand, complex to
implement, slow for encryption, and unsuitable for real-time and multimedia
applications. Hence many researchers used chaos-based cryptography.
Chaotic-based cryptosystems take full advantage of chaotic dynamics,
diffusion, and confusion performances to achieve adequate security.
In diffusion, ciphertext and plaintext form a complex relationship,
while confusion emphasizes how sensitive the ciphertext is to the plaintext.
A small change in the plaintext will significantly impact the ciphertext.
However, the main problem with most chaos-based algorithms is the
inadequacy of the chaotic maps they implement. Hence, most researchers
used more than one chaotic map or a higher dimensional chaotic map in the
system. We seek to develop new, secure, reliable, Symmetric, and
asymmetric cryptosystems based on chaos theory. We aim to incorporate
chaotic dynamics into cryptography to create new asymmetric and
symmetric algorithms using the lower dimensional chaotic map. The main
work can be summarized as follows:
i. We design and test a robust, efficient symmetric key stream cipher based
on chaos theory. The key was generated using based on a 3-dimensional
Logistic Map. The proposed techniques use a secure logistic map with
XOR operators and shift operations to perform encryption. The tests we
iv
conducted determined that the proposed scheme is cryptographically
sound and meets the needs of different analyses.
ii. The chaotic maps used in chaos-based cryptosystems in digital devices
show dynamical degradation with finite precision. Considering that
chaotic maps are based on real numbers, this has the disadvantage of
high computation costs and inefficient resource use. Hence, we used
both the real and imaginary parts of one superior logistic map for key
generation. An image is scrambled and diffused by combining a chaotic
sequence with a secret key entered by the user. The image is then
evaluated using various measures such as NPCR, UACI, MSE, PSNR,
and entropy.
iii. Based on the chaotic Tent map, we propose a secure and robust system
for the implementation of asymmetric key cryptosystems using chaos based techniques. For the construction of public and private keys, a salp
swarm optimization algorithm was used, along with a chaotic one
dimensional tent map, . In order to ensure good cryptography, the key
space must be large, so that brute-force attacks cannot be performed
against it, the secret key must be highly sensitive, and pseudo randomness should be employed in order to hide the correlation
between the key, the plaintext, and the ciphertext. It has been
demonstrated through security analyses and experiment results that the
proposed chaos-based cryptosystem is complex and provide confusion
and diffusion. | en_US |
