Sharif Digital Repository

One important aspect of privacy, is confidentiality. A common solution to preserve the confidentiality in network communications is ”Virtual Pri- vate Network”. VPNs todays are expected to be more secure and support higher throughput for their new applications, such as Inter-Cloud VPN and Virtual Private Cloud. block cipher is an important security com- ponent employed in most VPNs.On the other hand, most block ciphers have mathematical weaknesses in their structures, so the ttacker can use these weaknesses to break them faster than brute-force attacks. This thesis proposes a new method named ”Chaos-based Selective Key (CSK) Cryptosystem”, for increasing the security of block ciphers in a much... 

Security analysis of cryptographic systems against implementation attacks, including active and passive attacks, is an important issue due to the large number of such attacks in the real world. Since 2000’s, cryptographers have begun attempting to model active and passive attacks to implementation of cryptographic algorithms. At first, cryptographers modeled the attackers with ability to exploit leakaged information, leading to leakage-resilient cryptography. Afterwards, cryptographers modeled the attackers with ability to tamper with the cryptographic algorithms which led to tamper-resilient cryptography. Actually, the major proposed cryptographic primitive dealing with tampering is the... 

The Advent of Smart Grids has revolutionized the process of electricity transmission, distribution and delivery to consumers, significantly enhancing reliability and efficiency in compare to traditional power grids. In energy infrastructure, smart meters play a crucial role, which collects real time consumption data. such data enables advanced billing schemes, value added services for consumers, and operational services for grid management. Despite the advantages of smart grids and smart metering, they have introduced privacy challenges for consumers. consumption values are often containing sensitive information that can violate consumer privacy. For instance, such data can reveal household...