From Quantum Communication to Quantum Internet

有人说，人类对书面材料保密的愿望几乎和写作本身一样古老。随着互联网的兴起，加密的重要性越来越大。不幸的是，传统的加密方案通常基于计算假设，因此容易受到包括量子计算在内的算法和硬件的意外进步的影响。幸运的是，量子密码学提供了无条件的安全性-安全通信的圣杯-基于物理定律。量子加密网络目前正在中国和英国等国家建设。尽管如此，量子密码学的理论和实践之间存在很大的差距。量子黑客攻击威胁着实际量子密钥分发系统的安全。

It has been said that the human desire to keep written material a secret is almost as old as writing itself. With the rise of the Internet, the importance of encryption is growing. Unfortunately, conventional encryption schemes are often based on computational assumptions and are therefore vulnerable to unanticipated advances in algorithms and hardware including quantum computing. Fortunately, quantum cryptography offers unconditional security---the Holy Grail of secure communication---based on the laws of physics. Quantum cryptographic networks are currently being built in countries such as China and the UK. Nonetheless, there is a big gap between the theory and practice of quantum cryptography. Quantum hacking threatens the security of practical quantum key distribution systems.