Abstract:
The paper describes pseudo-random number generation based on non-linear dyanmica. The recommended generator uses a special "re-mapped" form of the logistc equation at each of a finite set of nodes arranged in a 1- or 2-dimensional ring. Each node receives small perturbations from adjacent nodes by means of diffusive coupling equations -- the so-called coupled map lattice. The generator is notable as the first to use non-linear dynamics in a lattice with a continuous state at each node. Time and space are discrete, but the state is continuous, unlike the cellular automata that Wolfram used to produce random numbers. It is a new source of pseudo-random numbers, unlike other current sources. The paper gives evidence that this generator possesses good statistical properties and a very long period, except in cases of negligible probability.
Abstract:
A fingerprinting Database Management System presents a unique version or view of the data to each user. The view contains small pseudo-random modifications to selected data items. The objective of this system is to identify users who divulge proprietary information which they have obtained through legitimate access. Even if the user makes further modifications to the data before its misuse, a statistical procedure will identify the source of the misuse with any desired degree of certainty.
Abstract: This article presents a randomized algorithm for leader election which uses bi-directionality of an asynchronous ring to force a node to "commit" to a coin flip by sending it in both directions. The algorithm is fault-detecting in a strong sense: it works if and only if there is a connected segment of ceil(n/2) +1 non-faulty processors (n = ringsize). Faulty processors may do anything to disrupt the algorithm---even communicate outside the ring and cooperate. The algorithm guarantees that each non-faulty processor in the segment either has probability 1/n of being elected leader or will receive a fault message.
Abstract:
Decimal-oriented error detection schemes are explored in the context of one particular company project.
Abstract:
This paper presents two specialized approaches to the design of a database incorporating cryptography in a fundamental way. Most processing is carried out on the encrypted version of the database at an insecure central site. Query initiation and final query interpretation occur at a secure local workstation. The first approach implements a text file with searches based on keywords. The second approach uses subfields and homophonic representations to create a secure database with fairly broad capabilities.
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.
Abstract:
This article suggests the use of undecidable problems in constructing public-key cryptosystems. Any such problem must still be in NP, but intuitive arguments suggest that this approach might be a reasonable alternative to the use of NP-complete problems. A general approach based on the undecidable word problem for groups is discussed, though without enough detail to evaluate a specific implementation. The resulting cryptosystem, if successful, would be a randomized public-key encryption procedure with infinitely many ciphertexts corresponding to each plaintext. Also, it is possible that a specific implementation could have infinitely many secret keys corresponging to one public key.
Abstract:
The undecidable word problem for groups and semigroups is investigated as a basis for a public-key cryptosystem. A specific approach does not give a provably secure or practical system, but shows the type of cryptosystem that could be constructed around the word problem. This cryptosystem is randomized, with infinitely many ciphertexts corresponding to each plaintext.
Abstract:
Plastic cards for different types of stored data are in wide use at present. Examples are credit cards and cards bearing access control information for automatic teller machines. More powerful devices with non-volatile read/write memory of several kilobytes, possibly with some intelligence, open new fields of applications in banking, administration, health care and communications. This paper describes a method for user verification and selective record protection in a network of terminals and one or more trusted Authenication Servers.
Abstract:
This paper presents a general discussion of the use of fingerprints, especially fingerprinted data. Fingerprinting is classified in four orthogonal ways, and some illustrative examples are given. The basis for a stastical analysis of altered fingerprints is prsented, along with an example simulation. The possibility of more subtle fingerprints is discussed.
Abstract:
A cryptography-based secure office system is discussed, including design criteria and a specific implementation. The system is intended to be pratical, simple, and inexpensive, but also highly secure. The implementation uses a hybrid scheme of conventional (DES) and public-key (RSA) cryptography. Randomly generated DES keys encrypt messages and files, and the DES keys themselves and a one-way hash of the messages are encrypted and signed by RSA keys. The system provides secure electronic mail (including electronic registered mail and an electronic notary public), secure two-channels, and secure user files. Timestamps and a special signed file of public keys help decrese the need for an online central authority involved in all transactions.
Abstract:
This article presents a two-stage encryption method for sharing access to a database where no single agency or device can ever encrypt or decrypt the data directly. Thus an attack by an opponent would have to succeed at two separate points. The main tool needed is a secure cryptosystem closed under composition: encrypting and re-encrypting using two successive keys is equivalent to a single encryption using some thrid key. An example cryptosystem satisfying this condition is exponentiation modulo a fixed prime.