Digest of Quantum Stream Cipher based on Holevo-Yuen Theory

Abstract

So far, quantum key distribution (QKD) has been the main subject in the field of quantum cryptography, but that is not quantum cryptographic communication, it is only the ability to send keys for cryptographic purposes. To complete cryptographic communication, a technique for encrypting data is necessary, and the conventional cryptographic technique of mathematical symmetric key cipher or One Time Pad (OTP) is adopted in the discussion so far. However, OTP is not the ultimate cipher for data encryption, because it does not satisfy security conditions in the modern cryptology. Around 2000, a new quantum stream cipher was proposed as a technique to challenge the possibility of overcoming drawbacks of OTP in practical use. Recently, we have published some review papers on it in Entropy (Open access journal), and others. This paper introduces an overview and a back ground of our paper that is entitled Quantum stream cipher based on Holevo-Yuen theory.