Patent ID: 7773747
Filing Date: 2010-08-10
Classification: H04L

Abstract:
1. An encryption apparatus for encrypting a message m on the basis of a fibration X(x, y, t)=0 of an algebraic surface X which is a public key, when private keys for decryption are two or more sections corresponding to fibration X(x, y, t)=0 of the algebraic surface X, the encryption apparatus comprising: an embedding device configured to embed plaintext M obtained by concatenating the message m to a random number r as the coefficients of plaintext polynomial M(t) with a variable t and of degree l−1 or less; a first polynomial generating device configured to generate random polynomials p(x, y, t) and q(x, y, t) with three variables x, y, and t on the basis of a hash value H(M) of the plaintext M; a second polynomial generating device configured to generate random one-variable irreducible polynomial f(t) of degree l or more; and an encrypted text generating device configured to generate encrypted text F=Epk(M, p, q, f, X) from the plaintext polynomial M(t) by an encrypting process of performing operations including at least one of addition, subtraction, and multiplication of the polynomials p(x, y, t), q(x, y, t), and f(t) and the fibration X(x, y, t)=0 with respect to the plaintext polynomial M(t).