Showing papers on "Plaintext-aware encryption published in 1992"

Cryptographic system and method

Abstract: I present a cryptographic communications system and method. The system includes a communications channel that is coupled to an encryption device and to a decryption device. A sender's plaintext message is encoded into ciphertext at the encryption device by first transforming the plaintext into a number sequence M. The encryption device couples the sender's signature S with an encoding key K to convert M into a ciphertext C. Ciphertext C is then transmitted over the communications channel to the intended receiver of the message. The receiver's decryption device acquires the ciphertext C. The decryption device takes the sender's signature S and the encoding key K and develops an inverted form of S which is the sequence T. The device uses T and K to decode C and obtain the digital message M. Sequence M is then converted to the original plaintext message. The sender's signature S is known at the encryption and decryption devices. S is kept secret from unauthorized persons. The encoding key K is developed by either of two alternatives. In one alternative, K is calculated as a sequence of numbers from the coupling of S with a sequence of random numbers R. In a second alternative, a sequence of random numbers R is developed in special relation to S and the encoding key K is then taken equal to R. In both alternatives, the sequence of random numbers R may be public. Any eavesdropper must have knowledge of the sender's signature S to decode the plaintext message. The cryptographic method for encryption, decryption, encoding key formation entails the consideration of each of the number sequences M, S, K, C, T, and R as the coefficients of polynomials that are in the finite field Z p of integers modulo the prime number p. The theory involved in the study of polynomials of this nature comes under the heading of Galois field theory. The calculations in the invention follow Galois theory but are performed using only the coefficients and not the actual polynomials.

A SOFTWARE IMPLEMENTATION OF THE McELIECE PUBLIC-KEY CRYPTOSYSTEM

Abstract: A software implementation of the McEliece public-key cryptosystem is presented together with some existing and new extensions. The important disadvantages of the scheme are the data expansion, the size of the keys and the fact that no digital signatures are possible. However, even a software implementation results in a reasonable speed of encryption and decryption. Moreover, the system can be used as a combined scheme that ofiers a both encryption and error correction at the cost of a decreased security level.

An RSA based public-key cryptosystem for secure communication

Abstract: A new cryptosystem that uses modulo arithmetic operations is proposed. It is based on Rivest-Shamir-Adleman’s public key cryptosystem. A feature of the proposed system is that the encryption and decryption procedures are computationally less intensive, and hence the system is amenable for high data bit rate communications.