Brief Overview: Quantum Cryptography

Quantum cryptography is a buzzword nowadays. We know that conventional cryptography plays a critical role in securing and protecting data by using complex mathematical problems. Conventional cryptography is based on computational mathematical techniques to achieve security. While quantum cryptography uses concepts of quantum physics to achieve security.

This blog provides you with a brief overview of quantum cryptography.

What is Quantum Cryptography?

Quantum Cryptography is a method of securing and encrypting data by using the concept of quantum physics. Note that the algorithm based on quantum cryptography is considered safe. It remains secure even if high computing power becomes available.

Quantum cryptography uses photons to transmit information on fiber optic cables. Although it seems to be easy, the complexity behind quantum physics is difficult to manage.

By using cryptography techniques, you can solve complex problems in a few hours. These are problems that took you a few months to solve before.

Concept	Description
Definition	Quantum Cryptography uses principles of quantum mechanics, like superposition and entanglement, to secure communication by ensuring privacy and integrity.
Key Principle	The security is based on the laws of quantum physics, which prevent eavesdropping without detection.
Main Technique	Quantum Key Distribution (QKD) is the primary method used in quantum cryptography to securely exchange encryption keys.
Quantum Superposition	Particles (e.g., photons) can exist in multiple states simultaneously, providing the ability to encode information in more complex ways.
Quantum Entanglement	Pairs of particles can be entangled such that the state of one particle directly affects the state of the other, even over large distances.
No-Cloning Theorem	A quantum state cannot be copied exactly, preventing an eavesdropper from intercepting and copying the quantum data without detection.
Measurement Effect	When an eavesdropper attempts to measure a quantum state, the act of measurement disturbs the state, which alerts the communicating parties.
Common Protocols	BB84 Protocol: The first and most widely used QKD protocol. E91 Protocol: Based on quantum entanglement for secure communication.
Eavesdropping Detection	Any attempt by an eavesdropper to intercept quantum communication will introduce detectable errors, alerting the sender and receiver.
Security Guarantee	The security is mathematically proven to be unbreakable as long as quantum mechanical principles hold true.
Applications	Secure communication (e.g., military, government). Financial transactions. Secure voting systems.
Challenges	Quantum hardware is expensive and difficult to scale. Environmental factors (e.g., noise) can interfere with quantum signals. Distance limitations in fiber-optic networks (currently).
Current Status	Quantum cryptography is in the experimental and early deployment phase, though significant progress is being made in real-world applications.

Quantum Cryptographic Algorithms

The National Institute of Standards and Technology (NIST) is developing quantum algorithms. These algorithms will be used under the post-quantum cryptography standardization project. Below are some algorithms identified by NIST and still evaluation is going on to test the strength of the algorithms.

(1) CRYSTALS-Kyber

General-purpose encryption is based on the hardness of solving the learning-with-errors (LWE) problem over module lattices.

(2) CRYSTALS-Dilithium

Used in the application of digital signature. The algorithm is based on a family of structured lattices.

(3) FALCON

Similar to Crystals-Dilithium, it is used in the application of digital signatures. The algorithm is based on a family of structured lattices.

(4) SPHINCS+

Used in the application of digital signature. The algorithm is based on a hash function.

Applications

Primarily quantum cryptography is used in distributing secrets (quantum key distribution) in insecure communication. This helps in securing secret keys from bad people.

To build trust between unknown parties, quantum cryptography will be used. This concept is called Mistrustful quantum cryptography.

Conclusion

Currently, NIST declared the 1024-bit version of the RSA encryption as unsafe and now recommends 2048 bits as a minimum. So, the lesson is clear, more length of the key, harder for the bad guy to compromise the IT system.