Research And Application Of Point Function Obfuscator

At present,China is in the era of rapid development of information,cloud computing and big data to bring convenience to people,but also poses a threat to people's privacy and security.Cryptography is the core of information and network security,and it provides guarantee for information protection.In recent years,the appearance of some new cryptography theories,obfuscation as a representative,can provide more reliable guarantee for information security.This paper starts from the theoretical knowledge of obfuscation,studies the construction and application of point function obfuscator,and then expands it,studies the construction of point function obfuscation with multi-bit output,and finally presents a content-concealing signatures scheme based on point function obfuscator.The main research content of this article is as follows:We introduce the theoretical knowledge of obfuscation and related cryptography knowledge,including the basics of computational complexity and provable security,as well as the random oracle model.Then starting from the origin of obfuscation,the definition of obfuscation and the definition of various relaxation forms are given,and the adversary's level of attack ability is divided.We study the point function obfuscation.Several construction methods of the point function obfuscator are introduced.The composability of the point function obfuscation is discussed.The impossibility results of the point function obfuscator under two conditions are given.Several applications of the point function obfuscator are briefly introduced.Based on this,we study the point function obfuscator with multi-bit output.At the same time,we introduce several ways to construct the point function obfuscator with multi-bit output,and point out the relationship between it and the symmetrical encryption scheme.We propose a content-concealing signatures scheme based on point function obfuscator.Because the point function obfuscator has practical application in information hiding,this paper applies the point function obfuscator(oracle hashing scheme)to the RSA signature algorithm to obtain a more secure digital signature scheme.Its security depends not only on the computational difficulty of the decomposition of large integers but also depends on the confidentiality of the point function obfuscator.The scheme not only hides the signed message,but also hides all partial information about the signed message.The ability to resist attacks is also greatly enhanced and the security is significantly improved.