Secret sharing schemes

Encryption or security of digital data have become increasingly important with the development of technology in daily life. Therefore, many encryption systems are being enhanced. Key security increases the importance of development of high-level manner against breakage encryption systems (Some systems may take years to resolve, even with the help of a computer).As key security determines the degree of a security of system, key keeping methods have been improved. The first solution that comes to mind is copying the key, but there are many disadvantages. The second is disintegration of key, and finally secret sharing method is improved.In this thesis, we will focus on developed methods for secret sharing system using the basic rules. Firstly, we point out that interpolation method is put forward independently by Shamir and Blakley.Secondly, as a generalization of the first method, we present the method which uses Reed Solomon codes developed by McEliece and Sarwate. The main point of this method is the coding scheme for Reed Solomon codes. It is shown that there are many advantages due to coding theory.Thirdly, we present the construction systems using Chinese remainder theorem and integer arrays of the specific order.Fourthly, we present that key systems can be constructed more quickly when a one to one mapping is established between the linear code and access sets developed by Massey. Secret sharing system has become feasible for all linear codes.Finally, we give some basic definitions and theorems about Fractional Repetition Codes. Next, we introduce a new method for constructing a secret-sharing scheme by making use of Fractional Repetition Codes.Key words: Key Storage Methods, Secret Sharing Scheme, Access Structure, Minimal Codeword, Linear Codes, Reed Solomon Code, Fractional Repetition Codes