In a recent paper, [Phys. Rev. A 65, 052326 (2002)], Mihara presented several
cryptographic protocols that were claimed to be quantum mechanical in nature.
In this comment it is pointed out that these protocols can be described in
purely classical terms. Hence, the security of these schemes does not rely on
the usage of entanglement or any other quantum mechanical property.Comment: 2 pages, revtex