A Construction of Public Key Cryptosystem for Realizing Ciphertext of Size 100 Bit and Digital Signature Scheme

Masao KASAHARA  Ryuichi SAKAI  

Publication
IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E87-A   No.1   pp.102-109
Publication Date: 2004/01/01
Online ISSN: 
DOI: 
Print ISSN: 0916-8508
Type of Manuscript: Special Section PAPER (Special Section on Cryptography and Information Security)
Category: Asymmetric Cipher
Keyword: 
public key cryptosystem,  simultaneous equations,  multivariate polynomial,  digital signature,  

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Summary: 
Extensive studies have been made of the public key cryptosystems based on multivariate polynomials. However most of the proposed public key cryptosystems of rate 1.0 based on multivariate polynomials, are proved not secure. In this paper, we propose several types of new constructions of public key cryptosystems based on two classes of randomly generated simultaneous equations, namely, a class based on bijective transformation and another class based on random transformation. One of the features of the proposed cryptosystems is that the sets of random simultaneous equations significantly improve the utilization factor of the transformation. We show an example of the proposed cryptosystem whose size of the ciphertext is only 100 bits.