Abstract.
The recent application of the principles of quantum mechanics
to cryptography has led to a remarkable new dimension in secret communication.
As a result of these developments, it is now possible to construct
cryptographic communication systems which detect unauthorized eavesdropping
should it occur, and which give a guarantee of no eavesdropping should it
not occur.
(54 pages)
1 Cryptographic systems before quantum cryptography . . . . . 3 2 Preamble to quantum cryptography . . . . . . . . . . . . . 7 3 The BB84 quantum cryptographic protocol without noise . . . 10 4 The BB84 quantum cryptographic protocol with noise . . . . 16 5 The B92 quantum cryptographic protocol . . . . . . . . . . 19 6 EPR quantum cryptographic protocols . . . . . . . . . . . . 21 7 Other protocols . . . . . . . . . . . . . . . . . . . . . . 25 8 Eavesdropping stategies and counter measures . . . . . . . 25 9 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . 26 10 Acknowlegment . . . . . . . . . . . . . . . . . . . . . . . 28 11 Addendum . . . . . . . . . . . . . . . . . . . . . . . . . 28 12 Appendix A. The no cloning theorem . . . . . . . . . . . . 29 13 Appendix B. Proof that an undetectable eavesdropper can obtain no information from the B92 protocol . . . . . . . . 30 14 Appendix C. Part of a Rosetta stone for quantum mechanics . 31 15 References . . . . . . . . . . . . . . . . . . . . . . . . 44
