  This paper analyzes the information-theoretical security of the Differential
Phase Shift (DPS) Quantum Key Distribution (QKD) protocol, using efficient
computational information geometric algorithms. The DPS QKD protocol was
introduced for practical reasons, since the earlier QKD schemes were too
complicated to implement in practice. The DPS QKD protocol can be an integrated
part of current network security applications, hence it's practical
implementation is much easier with the current optical devices and optical
networks. The proposed algorithm could be a very valuable tool to answer the
still open questions related to the security bounds of the DPS QKD protocol.
