  This paper introduces a novel entanglement-based QKD protocol, that makes use
of a modified symmetric version of the Bernstein-Vazirani algorithm, in order
to achieve a secure and efficient key distribution. Two variants of the
protocol, one fully symmetric and one semi-symmetric, are presented. In both
cases, the spatially separated Alice and Bob share multiple EPR pairs, one
qubit of the pair each. The fully symmetric version allows both parties to
input a secret key from the irrespective location and, finally, acquire in the
end a totally new and original key, an idea which was inspired by the
Diffie-Hellman key exchange protocol. In the semi-symmetric version, Alice
sends her chosen secret key to Bob (or vice versa). Furthermore, their
performance against an eavesdropper's attack is analyzed. Finally, in order to
illustrate the operation of the protocols in practice, two small scale but
detailed examples are given.
