Piracy protection in content distribution systems

摘要: In this thesis, we consider the traitor tracing problem. We study codes with different traceability properties and public key schemes. maximal 2-identifiable parent property. Using graph theoretic techniques, determine structure of representation length three having property, derive number codewords in such codes. Maximal property four have recently been studied. It is still an open problem to size a code greater than four. present direct construction 2-secure frameproof logarithmic length. This only known All other constructions short use recursive techniques. introduce new combinatorial object called difference function families which generalization matrices. families, that can apply small obtain larger same security Our techniques generalize some give better results. The most important advantage our technique it be applied all secure hash families. That is, codes, IPP TA separating perfect No linear attack on first scheme uses bilinear pairing. schemes decryption keys satisfy equation. show these must depend collusion threshold order resist attack. lower