Showing papers on "40-bit encryption published in 1983"

File access security method and means

Abstract: An improved file access security technique and associated apparatus accesses data which is stored in encrypted form under one encryption key and re-stores the data re-encrypted under another encryption key, and produces a record of each access and data re-encryption both as the control source of encryption keys for access and re-entry of encrypted data and as a secured audit record of users that had access to each file.

Recursive key schedule cryptographic system

Abstract: An encryption system in which a code word is processed, byte by byte, by a Vernan type process followed by non-linear encryption techniques, all of which are repeated several times, to generate a working key schedule. This key schedule is then used in the same process to encrypt the text.

Some Regular Properties of the ‘Data Encryption Standard’ Algorithm

Abstract: A cipher function y = E(k,x) should appear to be a random function of both the key k and the plaintext x Any regular behaviour is of interest to the users In the extreme case regular properties might point to a weakness of the cipher Precautions are needed in the use of a cipher that has regular features This note describes five regular properties of the ‘Data Encryption Standard’ or DES, two of which have been described elsewhere, are included for completeness

Modified Architecture for the Sub-Keys Model

Abstract: A secure implementation for subkey database encryption is presented. Both Vertical and Horizontal access to the control encrypted date are defined and described. Communication protocols between user and system are also provided.