Jian-Wei Pan: Breaking the Wall of Practical Satellite QKD | Science Summit 2025

The Challenge of Secure Communication

• ⚠️ Traditional encryption systems, like RSA, are vulnerable to powerful entities and can potentially be cracked by future quantum computers.
• 💡 The ultimate goal is to achieve true digital equality by providing an unbreakable encryption system accessible to everyone.

Quantum Key Distribution Fundamentals

• 🔑 Quantum mechanics offers a solution through Quantum Key Distribution (QKD), which generates unconditionally secure keys.
• 🔬 QKD utilizes quantum states, such as single photons or entangled photon pairs, which cannot be copied or cloned due to fundamental quantum principles.
• ✅ This inherent property ensures that QKD keys can never be broken, even by the most powerful supercomputers or quantum computers.

Extending QKD to Global Distances

• 🚀 Early QKD experiments were limited to very short ranges, such as 32 centimeters, due to significant photon loss over distance.
• 🛰️ The innovative solution to overcome atmospheric photon loss and achieve global reach for secure communication is the deployment of quantum satellites in space.
• 🌱 Over 20 years of dedicated research, including extensive ground tests at Qinghai Lake and with moving platforms, was crucial for developing satellite-based QKD.

Pioneering Satellite Quantum Communication

• 📡 In 2016, the Micius satellite was successfully launched, marking it as the world's first quantum science satellite.
• 🌐 Micius enabled satellite-to-ground QKD over distances exceeding 1,000 kilometers and distributed entangled photon pairs to two ground stations, ensuring security even if the satellite itself were compromised.
• 🤝 This groundbreaking technology allows for the linking of fiber-based QKD networks in various cities, contributing to a global quantum communication network.

Towards Practical Global Networks

• 🛠️ Recent advancements include the development of micro-satellites (e.g., G91), significantly reducing payload weight from 100 kg to 10 kg and ground station size from 10 tons to 100 kg.
• ⚡ These practical micro-satellites can generate 1 million bits of keys per orbit in real-time, making QKD more viable for widespread applications.
• 🌍 Collaborative efforts with organizations like the International Telecommunication Union (ITU) are underway to standardize quantum communication and integrate it into existing global communication infrastructures.