Showing papers on "Plaintext-aware encryption published in 1990"

A Statistical Attack of the FEAL-8 Cryptosystem

Abstract: This paper presents a chosen plaintext cryptanalysis of the FEAL-8 cryptosystem. The attack requires the ciphertext corresponding to approximately 10000 pairs of 64 bit plaintext blocks. The difference (bitwise xor) between the two blocks of each pair is equal to an appropriately selected constant. We first state that some differential statistics for intermediate values of the data randomizer are non uniform and independent of the encryption key. We then show that these statistics can be used to compute gradually the expanded key of the data randomizer.In 1989 some announcements were made that the so-called FEAL-8, 8 round version of the FEAL cryptosystem, was vulnerable to a chosen plaintext attack [1], So far, however, only the cryptanalysis of the 4 round version FEAL-4 by Bert Den Boer [2] was published. In this paper we present a chosen plaintext attack of FEAL-8 based on some differential statistics of its data randomization scheme.

Direct demonstration of the power to break public-key cryptosystems

Abstract: This paper describes a method of proving that a prover (or a crypt-analyst) really knows a secret plaintext or a new code-breaking algorithm for a particular public-key cryptosystem, without revealing any information about the plaintext or algorithm itself. We propose a secure direct protocol which is more efficient than the conventional protocols. This protocol requires only two transmissions between a prover and a verifier. A general form of the secure direct protocol is shown. The explicit forms for the RSA cryptosystem and the discrete logarithm problem are also proposed.