Showing papers on "Cipher published in 1976"

Television system transmitting enciphered data signals during field blanking interval

Abstract: A television system for broadcasting data simultaneously with but independently of television programs, in which digitally coded information carrying signals are superimposed or otherwise added to a video system in the field blanking interval. The local receiver is fitted with a decoder by means of which a viewer is able to select a particular page of supplementary information which is then superimposed over the broadcast program. Generally, this information is available to any member of the public who has a requisite decoder. In this system the digitally coded information carrying signals are enciphered prior to transmission in accordance with a predetermined key and the receiving terminal has a cipher circuit operable in accordance with the key to decipher the enciphered signals. In a preferred form each cipher circuit is a pseudo-random sequence generator for generating pulses in accordance with the predetermined key and the output of which is connected to one input of a gate, the other gate input being connected to the data signals. By enciphering the signals prior to transmission some pages can be dedicated for the private use of selected viewers to whom the cipher key is available.

Key controlled block-cipher cryptographic system employing a multidirectional shift matrix

Abstract: A cryptographic system for enciphering a block of binary data under the control of a unique key consisting of a set of binary symbols. A clear message represented in binary data format is transformed into a cipher message (and vise versa) by operating on blocks of clear information utilizing the operations of directional shifting of a derivative form of said clear data in a multidimensional matrix shifting and storage device. Further, cryptographic power is introduced to the system by performing a non-affine substitution operation during a shift operation on segments of information stored in said matrix. The shifting function, as well as the substitution function, is a function of said unique key. The system is further mathematically invertible, that is, the same hardware may be utilized for both encipherment and decipherment by merely reversing the sequence of operations.

Cipher computer and cryptographic system

Abstract: A system for the protection of stored and transmitted data including a random access memory accessed by counters and used for encrypting and decrypting signals in a cryptographic system using stream and block ciphers.

Encipering- and deciphering apparatus in the form of a typewriter

Abstract: An enciphering and deciphering apparatus in the form of a typewriter having an input device for the input of characters to be processed, a control device for the input of control commands determining the mode of operation of the apparatus and an output device possessing at least one page printer. A display device is connectable with the input device for the stepwise progressive display of the infed characters. The output side of the display device can be selectively connected with the printer, with a cipher computer or a key character storage associated with the cipher computer. The cipher computer has its output side connectable with the printer. A central control unit is provided which can be controlled by the control device. The central control unit fixes as a function of the infed control commands the data routes in the apparatus and controls the components of the apparatus, and depending upon the infed control commands the printer receives and prints the characters displayed by the display device or the characters produced by the cipher computer.

The voynich 'roger Bacon' cipher manuscript: Deciphered maps of stars

Abstract: A small, elaborately illustrated manuscript, written in cipher, and now in Yale's Beinecke Library, has often been referred to as 'the world's most mysterious manuscript'.1 It is also known as the Voynich manuscript, after the book dealer who rediscovered it in a Jesuit school in Frascati and acquired it in 1912, and as the Roger Bacon cipher because it has been attributed to Roger Bacon.2 Its history is worth recounting.3 It was given to Athanasius Kircher, the Jesuit polymath, in 1666; the letter of gift, still preserved, reports that the manuscript had formerly belonged to Emperor Rudolph II, patron of Tycho Brahe and Kepler, among others. Further, the letter goes, on, Rudolph had paid a fabulous price-6oo gold ducats-because he believed it to be 'the work of Roger Bacon, the Englishman'. On the first leaf, chemical treatment has brought out the signature of J. De Tepenecz, who had been a botanist in charge of the collection of Rudolph II. Details within the manuscript make it clear that this manuscript is not contemporary with Roger Bacon. From an alphabet including J, V, and W, to a fifteenth-century style of two-handed clock, one detail after another points to a later date.4 What is most conclusive, however, is Hugh O'Neill's identification in two illustrations of plants first brought to Europe by Columbus in I492.5 (I have subsequently identified two more as plants brought by Columbus in 1493.6) The date is therefore about 1500 at the earliest. But this says nothing about the date of the material incorporated in this treatise, nor the attribution to Roger Bacon. Two things make that attribution plausible. First, the illustrations indicate a sequence of topics exactly right for a treatise on the elixir of life, in which Bacon was reputed to be, and in fact was, keenly interested. Second, the key on the final leaf opens with a phrase, in mixed anagram and cipher, 'To me, Roger Bacon .. .'. The cipher is different from that used in the text itself, and this looks as though it could be the copy of a much earlier enciphered attribution. 7 The manuscript itself now has 204 pages; twenty-eight have been lost. It seems to divide into five main parts. It opens with a set of illustrations of plants, one to a page, as though it were a treatise on botany. There follows a * References in the footnotes are given in abbreviated form. Full information may be found in the bibliography on pp. 149-150. 1 See Manly, 'Mysterious MS', i921; Friedman, 1962. 2 Beginning with a letter accompanying its gift to A. Kircher in 1666; see below. 3 What follows is based on Newbold's account, in Newbold and Kent, 1928. 4 The Beinecke Catalogue suggests a 15thcentury date. The costume of the medallion of the Sa gittarius map; the two-handed clock on fol. 85; the style of Arabic numerals, for example in the margin of fol. 49r; a cipher box using distinct J, V, and W; all indicate that the date is at least that late.

Digital encoding for secure data communications

Abstract: : This thesis is concerned with the use of the digital computer to realize cryptography. Three cryptographic systems: simple substitution, pseudo-random cipher (polyalphabetic cipher), and data-keyed cipher, are designed, implemented through computer programming, and evaluated. A suitable cyclic error correcting code is designed to encode these systems for transmission. The code is tested by simulating a noisy channel.

A cipher device using photosemiconductors using

Abstract: PURPOSE:Unlocking device that is simple in structure and inhibits deciphering while permitting the ciphers to be modified.