A Provably-Secure Strongly-Randomized Cipher
- Ueli M. Maurer
- … show all 1 hide
Shannon’s pessimistic theorem, which states that a cipher can be perfect only when the entropy of the secret key is at least as great as that of the plaintext, is relativized by the demonstration of a randomized cipher in which the secret key is short but the plaintext can be very long. This cipher is shown to be “perfect with high probability”. More precisely, the enemy is unable to obtain any information about the plaintext when a certain security event occurs, and the probability of this event is shown to be arbitrarily close to one unless the enemy performs an infeasible computation. This cipher exploits the existence of a publicly-accessible string of random bits whose length is much greater than that of all the plaintext to be encrypted before the secret key and the randomizer itself are changed. Two modifications of this cipher are discussed that may lead to practical provably-secure ciphers based on either of two assumptions that appear to be novel in cryptography, viz., the (sole) assumption that the enemy’s memory capacity (but not his computing power) is restricted and the assumption that an explicit function is, in a specified sense, controllably-difficult to compute, but not necessarily one-way.
- J.L. Massey, An introduction to contemporary cryptology, Proceedings of the IEEE, vol. 76, no. 5, pp. 533–549, May 1988. CrossRef
- J.L. Massey and I. Ingemarsson, The Rip van Winkle cipher — a simple and provably computationally secure cipher with a finite key, in IEEE Int. Symp. Info. Th., Brighton, England, (Abstracts), p. 146, June 24–28, 1985.
- U.M. Maurer, Conditionally-perfect secrecy and a provably-secure randomized cipher, to appear in Journal of Cryptology, special issue EUROCRYPT’90.
- U.M. Maurer and J.L. Massey, Local randomness in pseudo-random sequences, to appear in Journal of Cryptology, special issue CRYPTO’89.
- U.M. Maurer and J.L. Massey, Cascade ciphers: the importance of being first, presented at the 1990 IEEE Int. Symp. Inform. Theory, San Diego, CA, Jan. 14–19, 1990 (submitted to J. of Cryptology).
- C.E. Shannon, Communication theory of secrecy systems, Bell Syst. Tech. J., vol. 28, pp. 656–715, Oct. 1949.
- G.S. Vernam, Cipher printing telegraph systems for secret wire and radio telegraphic communications, J. American Inst. Elec. Eng., vol. 55, pp. 109–115, 1926.
- A. Wyner, The wire-tap channel, Bell Systems Technical Journal, vol. 54, no. 8, pp. 1355–1387, Oct. 1975.
- A Provably-Secure Strongly-Randomized Cipher
- Book Title
- Advances in Cryptology — EUROCRYPT ’90
- Book Subtitle
- Workshop on the Theory and Application of Cryptographic Techniques Aarhus, Denmark, May 21–24, 1990 Proceedings
- Book Part
- Session 8:
- pp 361-373
- Print ISBN
- Online ISBN
- Series Title
- Lecture Notes in Computer Science
- Series Volume
- Series ISSN
- Springer Berlin Heidelberg
- Copyright Holder
- Springer-Verlag Berlin Heidelberg
- Additional Links
- Industry Sectors
- eBook Packages
To view the rest of this content please follow the download PDF link above.