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India is preparing to launch its first quantum satellite within 2-3 years as part of its National Quantum Mission (NQM), a significant initiative aimed at positioning India as a global leader in quantum technologies. This satellite will play a pivotal role in enhancing the security of communications, particularly in the face of the potential threat posed by quantum computers to existing cryptographic systems.

What is a Quantum Satellite?

A quantum satellite is a type of communication satellite that uses quantum physics principles to secure data transmission. Unlike conventional satellites that rely on classical encryption, quantum satellites leverage quantum mechanics to achieve unbreakable encryption through Quantum Key Distribution (QKD).

Key Features:

• Quantum Key Distribution (QKD): Ensures secure key sharing, revealing any attempts of eavesdropping.
• Security Advantage: Provides "unconditional security" by detecting any interference during the transmission process.
• Data Transmission: Unlike conventional satellites that encode data in classical bits, quantum satellites encode information in quantum states or qubits.

What is Quantum Cryptography?

Quantum cryptography is a technique that uses the laws of quantum mechanics to secure communications. The most widely used method is Quantum Key Distribution (QKD), which ensures that the keys used to encrypt and decrypt messages remain secret and unbreakable.

Key Mechanisms:

• Quantum Measurement: Any attempt to measure the quantum state (such as a photon carrying information) changes its state, alerting the sender and receiver to potential eavesdropping.
• Quantum Entanglement: When two quantum particles (photons) are entangled, a change in one will instantaneously affect the other, ensuring that the key remains secure.

Why is Quantum Satellite Important?

The advent of quantum computing threatens the cryptographic methods that secure current digital communications. Quantum computers, with their vast computational power, could potentially crack encryption codes that are currently deemed secure. Quantum satellites aim to counteract this threat by using quantum cryptography to make communications tamper-proof.

Security in the Quantum Era:

• Classical Encryption: Relies on mathematical problems that are difficult to solve without the decryption key.
• Quantum Encryption: Uses quantum properties, such as superposition and entanglement, to offer superior security.

National Quantum Mission (NQM)

The National Quantum Mission (NQM) was approved by the Union Cabinet in April 2023 with a budget of ?6,000 crore for implementation over eight years (2023-2031). The mission aims to accelerate the development and application of quantum technologies, with a focus on quantum communication, quantum computing, quantum sensing, and quantum metrology.

Key Objectives:

• Development of Quantum Computers: Building intermediate-scale quantum computers with 50-1000 qubits.
• Quantum Communication: Establishing secure, satellite-based quantum communication systems within India and internationally.
• Research and Innovation: Fostering quantum technologies and creating a self-reliant ecosystem.

India’s Advancements in Quantum Technology

India is making significant progress in quantum research and communication. The Raman Research Institute in Bengaluru has identified Hanle, Ladakh as an ideal location for quantum communication experiments due to its optimal atmospheric conditions.

The Indian Space Research Organisation (ISRO) has already demonstrated successful free-space quantum communication over short distances (300 meters). The upcoming quantum satellite will build upon this progress to create secure quantum communication networks within India and internationally.

Global Context: Micius Satellite and China’s Lead

China is a global leader in quantum communications, having launched the world’s first quantum satellite, Micius, in 2016. Micius demonstrated the feasibility of secure quantum communication by generating pairs of entangled photons. India’s quantum satellite will build on this technology to create robust, long-range quantum communication networks.

Limitations of Quantum Key Distribution (QKD)

Despite its promise, QKD faces several limitations:

• Technological Maturity: The technology is still in the experimental phase, and large-scale commercial implementation is not yet feasible.
• Authentication Issues: QKD lacks reliable methods to authenticate the transmission source, leaving it vulnerable to impersonation attacks.
• Infrastructure Costs: Establishing and maintaining QKD networks requires specialized hardware, leading to higher costs.
• Denial-of-Service Risks: Eavesdroppers can trigger the abort mechanism, leading to transmission interruptions.
• Signal Loss: Atmospheric and distance-related attenuation can degrade the quality of quantum signals.

National Quantum Mission and Sectoral Impact

The NQM aligns with India's national priorities, including Digital India, Make in India, and Start-up India. The mission’s outcomes are expected to impact various sectors, such as:

• Healthcare: Quantum computing for drug design and medical research.
• Space Exploration: Enhancing communication security for space missions.
• Banking and Financial Services: Strengthening data security and transaction integrity.
• Energy: Improving energy systems and smart grids through advanced sensing technologies.