Quantum Cryptography

Current public-key based cryptosystems rely on unproven assumptions about the complexity of finding the key for decoding the ciphered message, and are vulnerable to sudden advances in classical computer technology, better code-breaking algorithms, and the advent of the quantum computer. Based on the particular properties of single quantum systems, quantum cryptography allows information-theoretically secure key distribution, provided a short, secret key for authentication pre-exists. Quantum cryptography therefore removes the threat to current key distribution, and raises, as a part of a layered architecture, communication security on a fundamentally superior level. After a general introduction into quantum cryptography I will briefly discuss the current state of the art and address future challenges.