How Quantum Systems Can Unleash New Possibilities, Cybersecurity Risks

Quantum information systems harness the principles of quantum mechanics to process and transmit information in ways that classical systems can't achieve. These systems hold the potential to revolutionise various fields including computing, cryptography and communication, paying the way for innovation.

Quantum computing, with its very high computational power, provides opportunities and challenges. It revolutionises fields like drug discovery, material science, AI. At the same time, it poses a threat to the classical cryptographic algorithms such as RSA (Rivest–Shamir–Adleman), ECC (Elliptic Curve Cryptography) and AES (Advanced Encryption Standard) which are based on difficulty of solving specific mathematical problems like finding the prime factors of large numbers or solving discrete algorithms. These algorithms support our current digital security systems and today's internet. We are at the threshold of the quantum era in which the rules of classical computing are being redefined by the principles of quantum mechanics. This transformation promises unparalleled advancements but also brings new challenges particularly in safeguarding our digital future. For decades, binary logic has driven everything, smartphones to most powerful supercomputers.

Quantum Information Science (QIS)

Moore’s law states that the number of transistors in a dense IC (Integrated Circuit) doubles in about every 2 years. We have come to a stage where the dimensions of the transistor have reached a molecular or even atomic size. At atomic size, these transistors satisfy the laws of quantum mechanics. These quantum mechanical properties can be exploited for computing. This brings a lot of opportunities but also there is a major threat to classical systems.

The science of electromagnetism, established in the 1880s, is behind today's electronic information technology. Because of physical limitations, this technology will come to an end soon. QIS which exploits the laws of quantum mechanics, as defined in the 1900s, is a solution to overcome these limitations. QIS will lead to efficient computing, secure communications, high precision sensing and measurements beyond the present limitations. New cryptographic system will provide a higher level of security. One of the higher level security is Quantum Key Distribution (QKD) or Teleportation. Understanding of QIS requires knowledge of qubits, superposition, entanglement and unitary dynamics.

Superposition: In classical computing, information is represented by ‘0’s and ‘1’s. Quantum computing uses Qubit which can be ‘0’ or ‘1’ or both (superposition of both the states). This is the key property used in Quantum parallelism of computing. Computing in the quantum domain is efficient and super fast.

Entanglement: Once two quantum systems interact with one another, they become entangled partners. The state of one system will give precise information about the state of the other system, no matter what is the distance in between them. This is known as entanglement. In classical computing, entanglement is not possible.This entanglement enables transfer of information in ways that were previously unimaginable. This property is applied in Long- distance quantum communications, Quantum Cryptography and Quantum sensing.

Unitary Dynamics: It is irreversible in classical computing. For example, if you know the output of ‘AND’ gate, you can't find the input. Unitary Dynamics is reversible in Quantum computing. In quantum computing, if we know the output of the ‘AND’ gate, we can find the input. Implications of this property is, Quantum states can't be reproduced. Application of this property is in Quantum computing.

Implementation of qubits

Some Qubits occur naturally and others are engineered. Some of the most common types include:

Spin: Most quantum particles behave like magnets. This property is called spin. The spin orientation is always pointing either fully up or fully down. 0 pointing up, 1 pointing down. Using the spin states of up and down, we can build spin Qubit.

Trapped atoms and ions: We can use the energy levels of electrons in neutral atoms/ions as qubits. In their natural state, these electrons occupy the lowest possible energy levels. Using lasers, we can excite them to a higher energy level.We can assign the Qubit values based on their energy state. 0= low energy state, 1= high energy state.

Photons: We can use photons as Qubits.The two states used to define qubits are horizontal polarisation and vertical polarisation.

Superconducting circuits: We can design electrical circuits, based on superconductors, to behave like qubits. One way is by assigning a value to the direction of current flow. 0 = clock wise, 1 = anti clockwise.

Classical Bits vs quantum bits

1. Classical bits can be in two distinct states 0 and1. Quantum Bits can be in state 0 or in state1 or any other state that is a linear combination of these two states

2. Classical Bits can be measured completely. Qubits can be measured partially with given probability

3. Classical Bits are not changed by measurement. Qubits are changed by measurement. When measured they collapse to classical bits.

4. Classical Bits can be copied. Qubits can't be copied. This property is used in communications.

5. Classical Bits can be erased. Qubits can't be erased.

Classical computers use current flowing through circuits and gates which can be controlled and manipulated entirely by classical mechanics. Quantum computer uses laws of quantum mechanics to perform massively parallel computing through superposition and entanglement. Decoherence is a challenge in quantum computing which has to be addressed to have good Qubits. It is a physical process that occurs when a complex object interacts with its surroundings, causing the loss of quantum coherence resulting in the system's behaviour changing from quantum mechanics to classical mechanics.

The technology used in Quantum computers is Ion-trap, JJ (Josephson Junction).

Threats to Classical Cryptography

Cryptography is the Trust anchor for all our digital needs. Asymmetric algorithms of Classical Cryptography can be quantum attacked by Shor’s Algorithm with Key strength Quantum bits of even 0. Similarly, Symmetric algorithms can be quantum attacked by Grover’s Algorithm, with Key Strength Quantum bits which are just half of Key Strength Classical bits of Symmetric Algorithm.

SNDL (Store Now Decipher Later) threat: Someone can capture and store the encrypted data being transmitted now and decrypt it later, when today’s advanced encryption can be easily broken by quantum computers. While a classical computer would take 300 trillion years or more to decrypt a 2048 bit RSA encryption, a quantum one could crack it in seconds because of Qubits. So what is impossible to decrypt now can be easily done later, when quantum computers arrive.

This SNDL strategy is a looming threat in the cyber security landscape. This concept is not just theoretical, it is the next phase of cyber warfare and espionage. This is also called the Harvest Now and Decipher Later (HNDL) threat. Organisations and individuals may be unaware that their data is compromised by SNDL attacks. Lot of research is going on to address this problem. Post Quantum Cryptography (PQC) is the solution to mitigate this threat. The existence of this threat has led to the concerns about the need to urgently deploy PQC or Quantum Cryptography Resistant algorithms to overcome SNDL threat, even though no practical quantum attacks yet exist. This is because some encrypted data harvested now may still remain sensitive even after decades.

Michele Mosca’s Theorem: According to this theorem, if the amount of time that data must remain secure(X) plus the time it takes to upgrade the classical cryptographic systems by implementing quantum safe solution (Y) is greater than when quantum computers come online with enough power to break classical cryptography (Z), then we have to worry. If (X+Y)

Mosca’s theorem serves as a clear reminder of the need for organisations to begin applying diligence in the Post Quantum space right away. The US and other countries have already started preparations to migrate from classical Cryptography to PQC, as migration takes time. To mitigate the HNDL threat, a startup, Q Tino Labs Pvt Ltd, incubated at IIT Patna, is developing a solution.

As per Mosca ‘There is a 1 in 7 chance that some fundamental public-key crypto will be broken by quantum by 2026 and a 1 in 2 chance of the same by 2031.’

National Institute of Standards and Technology (NIST), which is part of the Department of Commerce US, conducted the 1st NIST workshop on PQC in 2015. In 2016, it announced a competition-like process for selecting PQC algorithms. After three rounds of analysis, in 2024 NIST selected three algorithms. They are:

1. FIPS (Federal Information Processing Standard) 203, Module- Lattice- Based Key- Encapsulation Mechanism Standard (ML-KEM) which is used for Key Encapsulation

2. FIPS 204, Module- Lattice-Based Digital Signature Standard (ML-DSA) which is used for Digital Signature

3. FIPS 205, Stateless Hash-Based Digital Signature Standard (SLH-DSA) which is also used for Digital Signature (Stateless means an application that doesn’t have information about a user’s previous interactions. Stateless applications are more fault-tolerant than stateful applications).

Quantum Key Distribution (QKD)

Quantum Key distribution is a system for ensuring secure communications. It enables two parties to produce and share a random secret key only between themselves which they can use to encrypt and decrypt their messages.

The security of QKD relies on the fundamentals of quantum mechanics compared to classical protocol which is based on the computational hardness of certain mathematical functions and can't provide any indication regarding possible interceptions.

An unique property of QKD is the ability of the two communicating users to detect the presence of a third party who tries to obtain information on the secret key, due to the fact that any measurement process disturbs the quantum system.

Applications of Quantum Computers

Quantum computers have many applications viz., Travel & Logistics, Chemistry, Pharmacology. Climate Modeling, Financial Analysis, Cryptography

Other applications:

1. Quantum factoring: A quantum computer can factorise numbers exponentially faster than classical computers. Shor's quantum algorithm can be used for factorisation. Against 1,50,000 years of time required to find out the prime factors of 29 digit decimal numbers on classical THz computer, less than 1 sec is required for the same using quantum THz computer.

2. Quantum Search: A quantum computer can find a marked entry in an unsorted database quadratically faster than classical computers, using Grover’s Algorithm

3. Quantum Simulation: application in Quantum Material Design

4. Quantum Optimization: Relevant to logistics, Operations Research, VLSI design, Finance

5. Quantum Networks: used for communications

Way forward

On 18.04.23, the union cabinet approved the setting up of the National Quantum Mission (NQM) at a cost of Rs 6,003 crores to be spent between 2023-24 and 2030-31. “The mission aims to seed, nurture and scale up scientific and industrial R&D and create a vibrant and innovative ecosystem in Quantum Technology (QT). This will accelerate QT-lead economic growth, nurture the echo system in the country and make India one of the leading nations in the development of Quantum Technologies and Applications (QTA)”. The Mission's objectives include developing intermediate scale quantum computers with 50-1000 physical qubits in 8 years in various platforms, including super conducting and photonic technology as per the DST (Department of Science & Technology) website.

“Satellite based secure quantum communications between ground station over a range of 2,000 km within India, long distance secure quantum communications with other countries, inter-city QKD over 2000 km, as well as multi-node quantum networks with quantum memories are some of the deliverables of the Mission,” the website says. Hope India will become the world leader in Quantum Technology!

(The author is Former Advisor, DOT, Government of India, Bangalore)