Showing papers on "Plaintext-aware encryption published in 1991"

A secret key cryptosystem by iterating a chaotic map

Abstract: Chaos is introduced to cryptology. As an example of the applications, a secret key cryptosystem by iterating a one dimensional chaotic map is proposed. This system is based on the characteristics of chaos, which are sensitivity of parameters, sensitivity of initial points, and randomness of sequences obtained by iterating a chaotic map. A ciphertext is obtained by the iteration of a inverse chaotic map from an initial point, which denotes a plaintext. If the times of the iteration is large enough, the randomness of the encryption and the decryption function is so large that attackers cannot break this cryptosystem by statistic characteristics. In addition to the security of the statistical point, even if the cryptosystem is composed by a tent map, which is one of the simplest chaotic maps, setting a finite computation size avoids a ciphertext only attack. The most attractive point of the cryptosystem is that the cryptosystem is composed by only iterating a simple calculations though the information rate of the cryptosystem is about 0.5.

A Known Plaintext Attack of FEAL-4 and FEAL-6

Abstract: We present new results on the cryptanalysis of the FEAL-N blockcipher. As a matter of fact, almost all the attacks of this cryptosystem published so far are chosen plaintext attacks [3,4,5,7], except the announcement in [7] of a non-differential known plaintext attack of FEAL-4 which requires about 100000 plaintext blocks. We describe known plaintext attacks of FEAL-4 and FEAL-6, which require about 1000 and 20000 plaintext blocks respectively and are based on correlations with linear functions. Using similar methods, we have also found more recently an improved attack on FEAL-4, which requires only 200 knwon plaintext blocks.

Caller identification system with encryption

Abstract: Telephone call identification service that safeguards the privacy of an originating station (calling party), while providing useful identifying information to a destination station (called party), is achieved by an encryption process. The encryption process includes combining the originating number with the telephone number of the destination station to form a message. Thereafter, the message is encrypted using the Data Encryption Standard (DES) or the Rivest, Shamir, Adleman (RSA) encryption algorithm to form ciphertext which is transmitted to the destination station. Using either encryption process, the ciphertext is reversible. A telephone switching office, preferably equipped with an electronic program-controlled switching system, executes the encryption algorithm and safeguards the keys used for encryption and decryption. When reversibility of the ciphertext is deemed to be undesirable, the telephone switching office uses modulo n processing of the ciphertext to render it non-reversible.

A cryptosystem for cellular telephony

Abstract: A relatively secure, self-inverting, symmetric key cryptosystem designed for efficient implementation on an 8-bit microcomputer. The cryptosystem is especially well suited use in cellular telephony. The method of encryption is comprised of three stages: 1) an autokeyed encryption, 2) the use of a one-time pad encryption where the key is derived from a portion of the message as encrypted by the first stage, and 3) a second autokeyed decryption that is the inverse of the first.

A private key cryptosystem based upon enforced random substitution scheme

Abstract: Proposes a private key cryptosystem in which a specially designed permutation table is used as an enciphering/deciphering key. By the permutation table, an enforced random substitution scheme substitutes the characters in a plaintext message. It is hard to guess the correct plaintext characters from known ciphertext characters. The secure measurement and some possible attacks on the proposed cryptosystem are also discussed. >

Yet another approach for secure broadcasting based upon single key concept

Abstract: Proposes a cryptosystem to solve the problem of broadcasting in a network. The cryptosystem has the following advantages: (1) only one ciphertext is sent out; (2) the operation of enciphering is performed only once; (3) the keys which are held by each user are the same as those of a public key cryptosystem: (4) the length of ciphertext is shorter than that previously proposed; (5) the sender can arbitrarily select the receivers who are requested to know the message: (6) digital signatures can easily be implemented: and (7) the security of the cryptosystem is the same as that of the RSA scheme. >

Encryption techniques for broadcast communication

Abstract: A broadcast technique for encrypted communication is proposed that offers high levels of security with high transmission efficiency. Any encryption algorithm can be used without significantly degrading ciphertext length. The proposed scheme can use parallel processing techniques to realize rapid encryption speeds. Plaintext is processed to yield one common component and as many individual components as there are receivers. Because the common component is used for all receivers, the ciphertext is relatively short. If a public key cryptosystem is used, any receiver's decrypted plaintext can be compared with that of another receiver, thus preventing malicious sender attack. >