The Boundary Problems Of Frameproof Codes

Digital fingerprint codes are widely used today,including frameproof codes,security frameproof codes,traceability codes,parent identification codes,etc.According to the different descendant model,digital fingerprint codes can be divided into four forms: narrow sense,extended narrow sense,broad sense and extended broad sense.This thesis mainly studies the frameproof codes(FP codes).In order to protect the content of material from illegal reproduction and dissemination,the publisher will mark each copy of materials.These marks can help publishers detect unauthorized copied materials and trace them back to unauthorized users so as to prevent unauthorized users from publishing unauthorized copied materials.This will help combat piracy and protect authorized users.In this thesis,we mainly discuss the boundary problems of frameproof codes when the descendant model alliance scale is 3 and the descendant model alliance scale is ω.Firstly,for the frameproof codes with the length of 5 and descendant model alliance scale is 3,an upper bound on the codeword capacity of frameproof codes is given by using the classification combination method based on the equivalence relation between frameproof codes and some structures.Then,the upper bound of frameproof codes with the length of 3ω+2 and descendant model alliance scale is w was discussed via the correlation between frameproof codes and hash function.