Developing cryptographic systems that can resist attacks from powerful quantum computers

“Three decades ago, three promising technologies emerged: AI, cryptography, and quantum computing. While AI has exceeded expectations, cryptography has played a pivotal role in securing the internet. Quantum computing, on the other hand, holds the promise of revolutionizing computing and delivering remarkable benefits for humanity. The future presents an exciting duel between cryptography and the realization of powerful quantum computers.”

In order for the Internet to fully unleash its potential as a platform for information sharing, diverse e-commerce endeavours, and remote private interactions, the public must have confidence that their transactions will be confidential and protected. Whether accessing personal data in online public databases, making a credit card purchase or holding online voting, the public must trust that the Internet is a secure place to do business. The bedrock of public trust is established on a science that has been employed for centuries – cryptography. Once confined to military, diplomatic, and governmental spheres, cryptography has now emerged as the pivotal cornerstone in realizing security within our interconnected world.

Cryptography establishes trust by ensuring that anyone attempting to breach the security of a protected online interaction faces the daunting challenge of solving complex mathematical problems. The sheer complexity of these problems is such that our current advanced computing technologies would require hundreds of years to solve them. The problems of integer factoring and computing discrete logarithms serve as crucial foundations for a significant portion of cryptographic systems known as public-key cryptography.

In 1994, mathematician Peter Shor made a groundbreaking discovery – an efficient algorithm that can solve both of the above problems. With this algorithm, virtually all currently deployed public-key cryptography can be compromised. Fortunately, Shor’s algorithm is not executable on conventional computers; it requires a quantum computer. However, at the time of Shor’s discovery, quantum computers only existed in theoretical form.

In recent years, there has been a significant amount of research on quantum computers. Small, laboratory-scale examples of quantum computers have been built. Some larger systems have also been proposed that can address some specific types of computation, but which may not be suitable for breaking current cryptographic systems. However, many quantum computing experts anticipate that sufficiently powerful quantum computers to break present-day public key cryptography will become available within the next 10 to 15 years.

“As the quantum computing era gradually unfolds, experts anticipate not if, but rather when and to what extent it will disrupt existing systems, potentially leading to the collapse of the internet. This pivotal moment puts the future of a secure and private internet on the line, carrying profound implications for the digital economy.”

To counter the potential threats posed by quantum computers, post-quantum cryptography (PQC) has emerged as an area of focus. PQC involves the development of new cryptographic systems that can be implemented on current classical computers while remaining resilient against attacks from quantum computers. The cryptographic community is actively exploring various approaches to build post-quantum cryptography, each based on different mathematical problems that are difficult to solve for both classical and quantum computers.

Working in the field of post-quantum cryptography can be exceptionally gratifying for mathematicians and computer scientists due to several reasons. Firstly, it offers an opportunity to tackle cutting-edge challenges and push the boundaries of mathematical and computational knowledge. Developing cryptographic systems that can resist attacks from powerful quantum computers requires novel approaches, innovative algorithms, and rigorous analysis, making it intellectually stimulating.

My research primarily focuses on lattice-based cryptography for post-quantum security, including the practical deployment of these cryptographic techniques. Adapting existing network security protocols to accommodate post-quantum cryptography requires substantial changes to ensure compatibility, efficiency, and interoperability. Our ongoing work in this field is currently supported by external grants from various labs of the Defence Research and Development Organisation (DRDO), the premier R&D organization of the country and the industry labs such as Mphasis F1 Foundation.

(Prof. Mahavir Jhawar is Assistant Professor of Computer Science at Ashoka University)