Practical proven secure authentication with arbitration

Proven secure signature schemes and unconditionally secure authentication schemes with arbiter have been proposed. The former are not practical (too slow) and the latter cannot be reused. All these limitations are solved in this paper by presenting a resuable conditionally secure authentication scheme with arbiter. The scheme is unconditionally secure against denial by the sender of having sent a message (which signatures do not have) and conditionally secure against a receiver impersonating the sender or substituting a message and conditionally secure against a similar fraud by the arbiter.