Showing papers on "Hybrid cryptosystem published in 1995"

Some Remarks on Lucas-Based Cryptosystems

Abstract: We review the well-known relation between Lucas sequences and exponentiation. This leads to the observation that certain public-key cryptosystems that are based on the use of Lucas sequences have some elementary properties their re-inventors were apparently not aware of. In particular, we present a chosen-message forgery for 'LUC' (cf. [21; 25]), and we show that 'LUCELG' and 'LUCDIF' (cf. [22, 26]) are vulnerable to subexponential time attacks. This proves that various claims that were made about Lucas-based cryptosystems are incorrect.

A New Key Escrow Cryptosystem

Abstract: The Escrowed Encryption Standard (EES) proposed by U.S. government has gained much attention in the last two years. It was claimed that EES can provide cryptographic protection to unclassified, sensitive data, while at the same time, allow for the decryption of encrypted messages when lawfully authorized. Later, some criticism was proposed to reveal the weakness of the EES proposal.

Implementation of a hybrid encryption scheme for Ethernet

Abstract: A software-based implementation of a hybrid encryption scheme for Ethernet LAN is given. It uses a DES-type symmetric key for information exchange between communicating users. In addition, a Diffie-Hellman method is adopted for key distribution which incorporates an RSA-type public key scheme for securing the exchange of the symmetric key components. To facilitate distribution of public keys and to guarantee authenticity, a separate network entity called security management facility (SMF) is deployed. A brief description of the software components for the proposed hybrid encryption scheme is given, and a Petri net representation of the software operation is provided. In addition, evaluation of the proposed scheme is carried out on a prototype network, and the numerical values for the encryption time and the message transfer time are obtained to illustrate the feasibility of the new scheme.

On Public-Key Cryptosystem Based on Church-Rosser String-Rewriting Systems (Extended Abstract)

Abstract: We propose an approach toward public-key cryptosystems based on finite string-rewriting systems with Church-Rosser property The approach utilizes an existence of unique normal form for any congruence class modulo such a system and possibility to find it in linear time Such cryptosystems can be used in the case we are dealing with a large network of communicating parties when it is impractical to use a distinct secret method signing for every pair users and we would like to have a unified secret method for all senders sending to a receiver

Key Escrow Cryptosystems

Abstract: Key escrow systems are those where part or all of the cryptographic keys are kept “in escrow” by third parties. The keys are released only upon proper authority to allow some person other than the original sender or receiver to read the message. The U. S. government is strongly supporting key escrow as a way to balance the needs for secrecy between communicating persons against the needs of law enforcement and national security agencies to sometimes read these encrypted communications (with proper legal authority). This chapter presents the technical aspects of the Clipper Chip, the U.S. Government’s first proposed key escrow system. It also mentions how Clipper fits into other proposed government cryptosystems and then presents a more general view of key escrow cryptosystems.

On a method of cryptanalysis for cryptosystem with involution

Abstract: Cryptology provides the technological basis for guaranteed network security. In the field of business, to guarantee the security of information, everyone needs easy-to-use cryptology. Starting with the announcement by the U.S. National Bureau of Standards of the DES cryptosystem and the proposal by NTT of the FEAL cryptosystem, secret-key cryptographic algorithms have been published, involution-type block cryptosystems which use secret key to encipher 64 bits of plain text as 64 bits of cipher text [2, 3, 9, 10, 12]. NTT has pro posed the one-way function MAP, which is also an invo lution-type transform. In this paper, we study a new cryptanalytic method for involution-type cryptosystems and show by example that it can be applied practically in a ciphertext-only attack on the one-way function MAP. For an involution-type cryptosystem, by increasing the amount of construction in the data-randomization phase and by increasing the size of the secret key, we can guarantee the computational security by preventing the estimation of the secret key. However, if we study the properties of the function used in the design of the data- randomization phase, by specifying input/output values of the function which are independent of the secret key, it may be possible to use the inverse function [11] to calculate the secret key. This method is called the inter Mediate cipher method. the intermediate cipher method differs from previous methods in the small quantity of data required for breaking.