DECRYPTION OF CIPHER POLYNOMIALS

摘要

A method of decrypting a cipher polynomial (e) using a private key (f) comprises: (a) Computing a trial polynominal (a), where a = f* e (mod q) and (q) is an integer; (b) Determining, on the basis of the trial polynomial (a), whether the polynomial (e) has decoded correctly, and if not: (i) determining which coefficient or coefficients of the trial polynomial (a) are likely to have caused the failure to decode; (ii) adjusting the said coefficient or coefficients to define a new trial polynomial; and (iii) attempting to decode the cipher polynomial (e) using the new trial polynomial. The method is particularly applicable to public key cryptosystems and, more particularly, to polynomial-based systems.