The strict avalanche criterion(SAC)is one of the most important cryptographic criteria for substitution boxes(S-boxes)used in many symmetric encryption systems.However,there are few constructive methods for S-boxes fu...The strict avalanche criterion(SAC)is one of the most important cryptographic criteria for substitution boxes(S-boxes)used in many symmetric encryption systems.However,there are few constructive methods for S-boxes fulfilling the SAC until now.In this paper,to construct S-boxes satisfying the SAC directly,we generalize the concatenation techniques of Boolean functions to S-boxes.Using the idea of concatenating small variable S-boxes,we present a simple yet effective construction method of S-boxes satisfying the SAC.Finally,a simple example on how to construct SAC S-boxes with large input variables by small variables SAC S-boxes is given.展开更多
The purpose of this paper is to design and implement a secure open database system for organizations that are increasingly opened up their information for easy access by different users. The work proposed some functio...The purpose of this paper is to design and implement a secure open database system for organizations that are increasingly opened up their information for easy access by different users. The work proposed some functionalities such as open password entry with active boxes, combined encryption methods and agent that can be incorporated into an open database system. It designed and implemented an algorithm that would not allow users to have free access into open database system. A user entering his password only needs to carefully study the sequence of codes and active boxes that describe his password and then enter these codes in place of his active boxes. The approach does not require the input code to be hidden from anyone or converted to place holder characters for security reasons. Integrating this scheme into an open database system is viable in practice in term of easy use and will improve security level of information.展开更多
基金Supported by the National Science Foundation of China(No.60773002,61072140)the 111 Project(No.B08038),the Doctoral Program Foundation of Institutions of Higher Education of China(No.20100203110003)+1 种基金the Fundamental Research Funds for the Central Universities(No.JY10000901034)the Anhui Provincial Natural Science Foundation(No.1208085QF119)
文摘The strict avalanche criterion(SAC)is one of the most important cryptographic criteria for substitution boxes(S-boxes)used in many symmetric encryption systems.However,there are few constructive methods for S-boxes fulfilling the SAC until now.In this paper,to construct S-boxes satisfying the SAC directly,we generalize the concatenation techniques of Boolean functions to S-boxes.Using the idea of concatenating small variable S-boxes,we present a simple yet effective construction method of S-boxes satisfying the SAC.Finally,a simple example on how to construct SAC S-boxes with large input variables by small variables SAC S-boxes is given.
文摘The purpose of this paper is to design and implement a secure open database system for organizations that are increasingly opened up their information for easy access by different users. The work proposed some functionalities such as open password entry with active boxes, combined encryption methods and agent that can be incorporated into an open database system. It designed and implemented an algorithm that would not allow users to have free access into open database system. A user entering his password only needs to carefully study the sequence of codes and active boxes that describe his password and then enter these codes in place of his active boxes. The approach does not require the input code to be hidden from anyone or converted to place holder characters for security reasons. Integrating this scheme into an open database system is viable in practice in term of easy use and will improve security level of information.
