Context: Researchers are working towards developing algorithms that can withstand attacks from both classical and quantum computers. As computational techniques evolve, the interplay between complexity and cryptography will continue to be a crucial area of research and development.
Relevance of the Topic: Prelims: Basic idea about Quantum Cryptography; Quantum Computing; National Quantum Mission.
What is Encryption?
- Encryption is a way of protecting data from unauthorised access or tampering. It works by transforming the data into a secret code that only the intended recipient can decipher.
- This comes in useful for various cases such as,
- securing online communications/ secure messaging systems
- verifying digital identities
- facilitating internet banking
- storing sensitive information etc.
Read More:End-to-End Encryption
Quantum Communication
- Quantum communication takes the advantage of the laws of quantum physics to protect data and securely transmit data.
- Traditional Encryption:
- In traditional data encryption, sensitive data is encrypted and sent through fibre optic cables with a digital key to decrypt the information.
- This data is transmitted in classical binary bits (0s and 1s) which makes it vulnerable to hackers who can read and copy it, without a trace.
- Quantum Encryption:
- In a quantum communication network, data is transmitted via quantum bits or qubits.
- Qubits are particles (usually photons of light) in a superposition state, i.e., they can be in multiple states and represent numerous combinations of 0 and 1.
- If a hacker tries to read this data, the qubits would collapse from their fragile quantum state to either a 0 or 1, thereby leaving a clear trace of external activity.
Quantum Cryptography
- Quantum cryptography, or quantum key distribution (QKD) ensures theoretically unbreakable encryption, making communications secure against any computational attack.
- How does QKD work?
- QKD uses a series of photons (light particles) to transmit a secure key between two parties over a fiber optic cable.
- By comparing measurements of the properties of some of these photons, the two parties can determine what the key is and if it is safe to use.
- If an eavesdropper tries to intercept the key, the photon’s quantum state changes, thus, revealing the intrusion attempt.
- In QKD, the eavesdropper cannot read the photon or make a copy of it, without being detected.
- A quantum state cannot be duplicated, according to the no-cloning theorem for quantum physics.
- An attacker can not replicate the quantum information being communicated and manipulate their copy.
- Quantum states would no longer be in a superposition, if an attacker attempted to read out data through an entanglement-based protocol.
Associated Challenges
- Technical limitations:
- Quantum decoherence: Present technologies to realise qubits are based on superconducting junctions, trapped ions and quantum dots. These qubit systems are very fragile and susceptible to losing their quantum state.
- High cost: Quantum key distribution requires high infrastructure costs, as qubits are only stable at very low temperatures or in a high vacuum or both, which are expensive to maintain.
- Building quantum resistant cryptography:
- A mature quantum computer could easily break some encryption methods widely used today. In that case, the current cryptosystems will fail.
- The present challenge of quantum cryptography is to build quantum-secure cryptosystems i.e., algorithms that can resist attacks powered by a quantum computer.
Developments in India in the Quantum field
- National Quantum Mission:
- The National Quantum Mission was approved in 2023 and includes building a research hub for quantum communication.
- The mission is to enable:
- satellite-based secure quantum communications between ground stations over 2,000 km
- long-distance secure quantum communications with other countries
- inter-city quantum key distribution over 2,000 km
- multi-node quantum networks etc.
- Quantum satellite: The Indian Space Research Organisation is planning to launch a satellite with ultra-secure quantum communication capabilities.
Read More: India’s Quantum Future