Showing papers on "Transposition cipher published in 1986"
Proceedings Article•
01 Jun 1986
TL;DR: During summer 1985, eight cycling experiments on the Data Encryption Standard (DES) were performed to see if DES has certain algebraic weaknesses, and the results show with overwhelming confidence that DES is not pure.
Abstract: During summer 1985, we performed eight cycling experiments on the Data Encryption Standard (DES) to see if DES has certain algebraic weaknesses. Using special-purpose hardware, we applied the cycling ciosure test described in our Eurocrypt 85 paper to determine whether DES is a pure cipher. We also carried out a stronger version of this test, (A cipher is pure if, for any keys i,j,k, there exists some key l such that TiTj-1Tk = Tl, where Tw denotes encryption under key w.) In addition, we followed the orbit of a randomly chosen DES transformation for 236 steps, as well as the orbit of the composition of two of the "weak key" transformations. Except for the weak key experiment, our results are consistent with the hypothesis that DES acts like a set of randomly chosen permutations. In particular, our results show with overwhelming confidence that DES is not pure. The weak key experiment produced a short cycle of about 233 steps, the consequence of hitting a fixed point for each weak key.
20 citations
01 Jan 1986
TL;DR: This paper discusses the use of an arbitrary bit-sequence generating algorithm as the cryptographic key for a stream cipher with emphasis on methods for combining stream generators into more complex ones, with and without randomization.
Abstract: This paper discusses the use of an arbitrary bit-sequence generating algorithm as the cryptographic key for a stream cipher. Emphasis is placed on methods for combining stream generators into more complex ones, with and without randomization. Threshold schemes give a generalization of many combination techniques.
2 citations
TL;DR: The AMSCO cipher is an incomplete-columnar transposition cipher that lends itself to machine solution, and the regularity of the transposition makes it possible to write a computer program that will try all combinations of various keyword lengths, and to check for the presence of likely words (cribs) in the answers.
Abstract: The AMSCO cipher is an incomplete-columnar transposition cipher that lends itself to machine solution. The regularity of the transposition makes it possible to write a computer program that will try all combinations of various keyword lengths, and to check for the presence of likely words (cribs) in the answers. If a genuine crib is available, such as those provided in examples in “The Cryptogram”, a positive answer can be determined. If no crib is available, then it is necessary to try the most popular words in the vocabulary. A 99 per cent success rate seems possible, without knowing either the keyword length or a crib word.
1 citations