Showing papers on "Two-square cipher published in 1985"
Patent•
IBM1
TL;DR: In this paper, a product cipher is proposed for decoding a stream of binary data by means of a product function (PMF) which is dependent on previous internal cipher digits fedback and varies for each message bit processed.
Abstract: of EP0035048This is a cipher system for enciphering or deciphering a stream of binary data by means of a product cipher. A clear message (16) represented in a binary data format is transformed into a cipher message or vice versa by operating on each consecutive bit of clear information with a complex modulo-two addition function (18). This function is dependent on previous internal cipher digits fedback (24) and varies for each message bit processed. The function is developed by continually shifting a key matrix (10) under the control of a varying control matrix (34). The control matrix is formed from the subproducts (24) of the complex function (18) developed in generating each cipher bit (22).
4 citations
TL;DR: The cipher presented here is trigraphic, because triple of letters are mapped into triples of letters, and it is truly tri-graphic because all three letters of the triple are treated in the same fashion.
Abstract: The cipher presented here is trigraphic, because triples of letters are mapped into triples of letters, and it is truly tri-graphic because all three letters of the triple are treated in the same fashion. The key consists of a square or rectangular array of letters (like that used for the Playfair), which must have an odd number of rows and an odd number of columns. The cipher is a very simple algebraic cipher, but it is suitable for hand ciphering and deciphering. It is believed to be almost as easy to use as a Play-fair or Delastelle, and possibly more secure against cryptanalysis.
1 citations
TL;DR: This paper presents a non-numerical polygraphic substitution cipher which appears more efficient than Hill's algebraic system, and the source of the greater efficiency is that the number of letters which can be jointly enciphered is exponential, rather than linear, with respect to thenumber of operations performed.
Abstract: This paper presents a non-numerical polygraphic substitution cipher which appears more efficient than Hill's algebraic system. For instance, by using the same number of “operations” per message as a 6-graphic algebraic substitution cipher, the present cipher can achieve 4096-graphic substitution. Less dramatically, a 16-graphic application of the present cipher requires only one-eighth as many operations as a 16-graphic algebraic cipher. The source of the greater efficiency of the proposed cipher is that the number of letters which can be jointly enciphered is exponential, rather than linear, with respect to the number of operations performed.
1 citations