Showing papers on "Encryption published in 1976"
Dissertation•
01 Jan 1976
TL;DR: This thesis develops a complete set of protocols, which utilize a block cipher, e.g., the NBS data encryption standard, for protection interactive user-computer communication over physically unsecured channels, and discusses the results of a test implementation of the modules on Multics.
Abstract: Thesis. 1976. M.S.--Massachusetts Institute of Technology. Dept. of Electrical Engineering and Computer Science.
29 citations
01 Jun 1976
TL;DR: In this article, a complete set of protocols, which utilize a block cipher, e.g., the NBS data encryption standard, for protection interactive user-computer communication over physically unsecured channels.
Abstract: This thesis develops a complete set of protocols, which utilize a block cipher, e.g., the NBS data encryption standard, for protection interactive user-computer communication over physically unsecured channels. The use of the block cipher protects against disclosure of message contents to an intruder, and the protocols provide for the detection of message stream modification and denial of message service by an intruder. The protocols include facilities for key distribution, two-way login authentication, resynchronization following channel disruption, and expedition of high priority messages. The thesis presents designs for modules to implement the protocols, both in the terminal and in a host computer system, and discusses the results of a test implementation of the modules on Multics.
25 citations
07 Jun 1976
TL;DR: The building-block approach outlined makes use of pre-programmed software elements for providing all specialized algorithms, including the Proposed Federal Data Encryption Standard (DES), together with necessary nonnumeric generalized support routines for use with application programs written in conventional procedural higher languages.
Abstract: Protection of information within a computer/communication system can be provided through reversible cryptographic transformation of the information itself into a form that can be returned to usable form only through use of control information known as "key."It is not necessary, in order to achieve access control, that the encryption algorithms, random number generator, or system organization be kept secret; in fact, a basic requirement of modern cryptographic technology is that it must be effective although a would-be penetrator is assumed to have full access to all of that information and the facilities and competence to apply it. Only the key can be assumed to be, and must be, physically secure.The building-block approach outlined makes use of pre-programmed software elements for providing all specialized algorithms, including the Proposed Federal Data Encryption Standard (DES), together with necessary nonnumeric generalized support routines for use with application programs written in conventional procedural higher languages (FORTRAN, COBOL, etc.). Both Strong Algorithm and Long Key methods can be used as required by security-level-vs-cost tradeoff considerations.This method is useful in conjunction with specialized hardware; for testing of programs and hardware; in some cases instead of hardware; and can support multiple-level security applications.The entire scheme, including the Tausworthe-Lewis-Payne bitwise linear recurrence modulo 2 quasirandom number generator, is based irrespective of hardware type on a standardized 64-bit data element.
11 citations
TL;DR: This paper considers temporal rearrangement or scrambling of the lpc code sequence, as well as the alternative of perturbing individual samples in the sequence by means of pseudo-random additive or multiplicative noise.
Abstract: This paper discusses several manipulations of lpc (linear predictive coding) parameters for providing speech encryption. Specifically, the paper considers temporal rearrangement or scrambling of the lpc code sequence, as well as the alternative of perturbing individual samples in the sequence by means of pseudo-random additive or multiplicative noise. The latter approach is believed to have greater encryption potential than the temporal scrambling technique, in terms of the time needed to “break the secrecy code.” The encryption techniques are assessed on the basis of perceptual experiments, as well as by means of a quantitative assessment of speech-spectrum distortion, as given by an appropriate “distance” measure.
8 citations
07 Jun 1976
TL;DR: In most cases it is theoretically possible for an outside observer to identify the key after very few observations, but as this must be avoided the authors have to rely on computational complexity in the process of deriving the key.
Abstract: In computer cryptography we cannot avoid that data and the corresponding encrypted data can be read by an outside observer. The information contained in these observations may be used to decrypt parts of encrypted data or ultimately to identify the key in the cryptographic transformation. In this paper we have analyzed this situation using the concepts of information theory. The result shows that in most cases it is theoretically possible for an outside observer to identify the key after very few observations. As this must be avoided we have to rely on computational complexity in the process of deriving the key. This is achieved by using one-way functions which are practically impossible to invert.
2 citations
TL;DR: This paper considers temporal rearrangement or scrambling of the LPC code sequence, as well as the alternative of perturbing individual samples in the sequence by means of pseudorandom additive or multiplicative noise.
Abstract: This paper discusses several manipulations of LPC (linear predictive coding) parameters for providing speech encryption Specifically, the paper considers temporal rearrangement or scrambling of the LPC code sequence, as well as the alternative of perturbing individual samples in the sequence by means of pseudorandom additive or multiplicative noise The latter approach is believed to have greater encryption potential than the temporal scrarabling technique, in terms of the time needed to “break the secrecy code” The encryption techniques were assessed on the basis of perceptual experiments, as well as by means of a quantitative assessment of speech‐spectrum distortion, as given by an appropriate “distance” measure
2 citations
24 Mar 1976
TL;DR: The techniques that apply and, in particular, those that provide for better security, are more readily implemented in a system with common channel signaling where signaling speeds are considerably faster than those that are used in present-day practice.
Abstract: Various levels of protection from unauthorized use of a mobile-telephone service can be provided where the exchange for the service is under stored-program control. The security techniques that provide this protection can be upgraded on a per-subscriber or per-system basis as the incidence of unauthorized use increases. The "ultimate" arrangement provides for the encryption of variable passwords. Proper protection of auxiliary storage devices precludes compromise of the cipher-keys assigned to individual mobile units. The techniques that apply and, in particular, those that provide for better security, are more readily implemented in a system with common channel signaling where signaling speeds are considerably faster than those that are used in present-day practice.