Based on tetra-peptide structural words,the central residues for those sequence fragments are predicted using the method of diversity increment combined with quadratic discriminant analysis(for short IDQD).

This paper aims at the ordinary security for the state documents examination and approval in office automation system and expounds a new encryption and digital signature algorithm—quadratic residue algorithm on the base of data integration proving in order to encypt the state documents examination and approval.

A Research on Quadratic Residue-Based Mixed Software Watermark;

Secret sharing scheme of secure vector space based on quadratic residue;

Cryptoanalysis of cryptosystems based on the quadratic residue problem;