[Here is the conclusion to my QC paper, unfortunately I can't get the whole file into a PS format because of the faulty file translators in the Mac applications.] Conclusion Quantum cryptography has proven to be an interesting and novel application of quantum physics. It does posses some severe limitations that I have considered. Optimistic predictions of itÕs affective area is still far below 100 km. This may of course change depending on technological development. It has been suggested to me that one could have secure stations where interception and reception of the message would be allowed. [10] This is possible, but weakens the ÔabsolutenessÕ that is the appeal of quantum cryptography. A basic assumption is made previous to the research mentioned: that Eve will not interfere on the public channel. It could be very possible that Eve would set herself up between Alice and Bob on the quantum and private channels, and act as a relay station that I mentioned in the first point. She would have to impersonate both Alice and Bob, who in reality might not even be on the same public and quantum channels, but merely think they are. Public key methods could be used for authentication, but this destroys the motivation for the use of quantum cryptography. I feel the solution here is in the definition of ÒpublicÓ. Meaning a random and public switching of public channels, phone numbers and such. Even this may be subverted by a very powerful Eve who may also control the phone companyÕs switching circuits. Perhaps further thought can resolve this issue, but the problem of identification and authentication on the public channel is severe. Further, quantum cryptography is subject to a denial of service attack. If Eve wishes, she may destroy the unique and expensive quantum channel, or merely observe everything that goes by, not caring to read the information, just making it unsuitable for use by Alice and Bob. EkertÕs concept of keeping shared EPR pairs in permanent storage (perhaps using a superconductor to warehouse keys when the quantum channel is open) is not yet feasible, and it will be necessary to keep these keys somewhere , but the security of keys is not a problem unique to quantum cryptography. I look forward to the resolution of these issues and the further development of the technology that will allow quantum cryptography to become a ÔpracticalÕ security mechanism. 1. C. Bennett. Science.. vol. 257, p. 752 (August, 1992). 2, C. Bennett, G. Brassard, and A. Ekert. Scientific American. p. 50 (Oct., 1992) 3. A. Ekert, Phys. Rev. Lett. vol. 67, p. 661 (1991) 4. C. Bennet, and G. Brassard, Phys. Rev. Lett. vol. 68, p. 557 (1992) 5. A. Ekert, J. Rarity, P. Tapster, and G. Palma, Phys. Rev. Lett. vol. 69, p. 1293, (1993). 6. A. Muller, J. Breguet, and N. Gisin. Europhs. Lett., vol. 23 (6), p. 383 (1993). 7. S. Barnett, and S. Phoenix. Phys. Rev. A, vol 48 (1), p. R5, (July, 1993). 8. C. Bennett. Phys. Rev. Lett. vol 68 (21), p. 3121 (1992) 9. D. Denning. Cryptography and Data Security. 10. Personal e-mail as a follow-up to a posting to sci.crypt. I have unfortunately lost the personÕs name.