1. G. S. Vernam, J. Am. Inst. Electr. Eng. 55, 109 (1926).
2. C. E. Shannon, Bell Syst. Tech. J. 28, 658 (1949).
3. W. Diffi and M. E. Hellman, IEEE Trans. Inf. Theory 22, 644 (1976).
4. R. L. Rivest, A. Shamir, and L. Adleman, Commun. ACM 21, 120 (1978).
5. P. W. Shor, in Proceedings of 35th Annual Symposium on the Foundations of Computer Science, Santa Fe, NM, USA, 1994 (IEEE Computer Soc. Press, Los Alamitos, CA, 1994), p. 124; quant-ph/9508027.