Foundations and practical studies of secure computation

Ronald Cramer

Mikhail Pavlov

Abstract This guide focuses on symmetric-key cryptography (SKC) as part of quantum-safe cryptographic practices using IBM Q. Symmetric-key cryptography protects the majority of data in storage and transmission due to its efficiency and simplicity. In SKC, the same secret key (ssk) is used for both encryption and decryption, forming the foundation for many practical cryptographic systems. The lesson includes: A detailed introduction to symmetric-key cryptography principles. Python code examples demonstrating symmetric-key encryption (SKE) and decryption. Analysis of practical applications in securing data at rest and in transit. Evaluation of security considerations, including vulnerabilities to classical and quantum computing attacks. Insights into the evolving threat landscape in the quantum era and steps for mitigating risk. By combining theoretical foundations with hands-on experimentation on IBM Q, developers can understand the role of symmetric-key cryptography in quantum-safe systems and gain practical skills for implementing secure encryption schemes in preparation for quantum computing threats.

Yuval Ishai

Wajdi Fawzi Mohammed Al-Khateeb, Khalid A. Saeed Al-Khateeb, Nur Elyana Ahmad +1 more

The advancement of the quantum computing is challenging the foundation of the cryptography by its almost unlimited computation power to predict the secure key that is thought to be absolutely secure based on the currently used algorithms such as the RSA and the Diffie-Hellman and others. The field of quantum cryptography on the other hand is providing the needed highly secure keys through the introduction of quantum key distribution QKD when the quantum computing becomes a reality. However, the quantum cryptography and the QKD are challenged in many ways, not only to provide the advanced level of technology but also to overcome many constraints to provide a worldwide practical distribution system as well as to provide the efficiency to overcome the very modest size of the quantum keys. In this paper, practical factors affecting realistic QKD are investigated supported by related simulation based analysis.

Geoffroy Couteau

Rafael Dowsley

Correlated data can be very useful in cryptography. For instance, if a uniformly random key is available to Alice and Bob, it can be used as an one-time pad to transmit a message with perfect security. With more elaborate forms of correlated data, the parties can achieve even more complex cryptographic tasks, such as secure multiparty computation. This thesis explores (from both a theoretical and a practical point of view) the topic of cryptography based on correlated data.