Although key distribution is arguably the most studied context on which to apply quantum cryptographic techniques, message authentication, i.e., certifying the identity of the message originator and the integrity of the message sent, can also benefit from the use of quantum resources. Classically, message authentication can be performed by techniques based on hash functions. However, the security of the resulting protocols depends on the selection of appropriate hash functions, and on the use of long authentication keys. In this paper, we propose a quantum authentication procedure that, making use of just one qubit as the authentication key, allows the authentication of binary classical messages in a secure manner.

• Received 22 March 2001

DOI:https://doi.org/10.1103/PhysRevA.64.062309