Method and system for encoding and decoding digital message

Abstract

The invention provides a method used in the coding and decoding digital information and a system, comprising: selecting positive integers m, n', wherein m is not smaller than n'; generating a public key including E'(x), wherein E(x) is the nonlinear mapping function group from (x(1),...x(m)) to (y(1),...y(n')), and E'(x) includes n' functions including the rational fraction functions about (x(1),...x(m)); generating a private key corresponding to the public key, then completing the corresponding public / private key encrypting / decrypting process, or completing the corresponding public / private key signature verification process. The invention has markedly increased encrypting function scale. According to the invention, the secondary sparse polynomial of MQ is advanced as the high order densepolynomial, to case the scale of the polynomial function equal to the public key to explode, thereby increasing the difficult of the inverse function to solve the indeterminate equations, thereby markedly increasing the anti-deciphering ability.

Description

technical field [0001] The invention relates to the field of information encoding and decoding, in particular to a public key cryptosystem for encrypting, decrypting, signing and verifying data messages. Background technique [0002] Cryptography is a science and technology that studies encryption and decryption transformations. Usually, people refer to understandable text as plaintext; the unintelligible text transformed from plaintext is called ciphertext. The process of converting plaintext into ciphertext is called encryption; the inverse process, that is, the process of converting ciphertext into plaintext is called decryption. This encryption or decryption transformation is controlled by a key. A cryptographic system used in an open environment should meet the following basic requirements: [0003] Confidentiality: ensure that information is not leaked to unauthorized users; [0004] Integrity: ensuring that information is not modified arbitrarily or deliberately; ...

AI Technical Summary

Problems solved by technology

[0018]2. Can only sign, not encrypt

[0022]Of course, if the number n of polynomials and the number m of variables in its public key (that is, the encryption algorithm) are set to be the same, let its public key become a permutation equation group, instead of an indeterminate equation group, although the signed data a can be restored from the signature b (that is, it has the function of encryption), it is easy to be deciphered

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