Abstract
When it became known that quantum computers could
break the RSA (named for its creators - Rivest, Shamir,
and Adleman) encryption algorithm within a
polynomial-time, quantum cryptography began to be
actively studied. Other classical cryptographic
algorithms are only secure when malicious users do not
have sufficient computational power to break security
within a practical amount of time. Recently, many
quantum authentication protocols sharing quantum
entangled particles between communicators have been
proposed, providing unconditional security. An issue
caused by sharing quantum entangled particles is that it
may not be simple to apply these protocols to
authenticate a specific user in a group of many users.
An authentication protocol using quantum
superposition states instead of quantum entangled
particles is proposed. The random number shared
between a sender and a receiver can be used for
classical encryption after the authentication has
succeeded. The proposed protocol can be implemented
with the current technologies we introduce in this
paper.