A Hybrid Protocol for Quantum Authentication of Classical Messages

Quantum authentication of classical messages is discussed. We propose a non-interactive hybrid protocol reaching informationtheoretical security, even when an eavesdropper possesses infinite quantum and classical computer power. We show that, under certain conditions, a quantum computer can only distinguish a sequence of pseudo random bits from a truly sequence of random bits with an exponentially small probability. This suggests the use of such generator together with hash functions in order to provide an authentication scheme reaching a desirable level of security.