Threshold Cryptography On Dsp

Cryptography is the core of security technologies, and encryption, decryption, digital signature, key exchange etc. are the important mechanisms to guarantee the safety. According to symmetric algorithm, public key algorithm and digital signature, the safety of key is most important. Once the key is let out, the whole system will collapse, and all the files encrypted and messages signed will be insecure and unreliable. So, how to do the better security protection and enhance the defend ability of system, will directly touch the implementation of cryptography algorithm in practice.About key management, there have been many important technologies, such as the theory of secret trusteeship raised by American in 1993, X.509 (which has run to the third edition) standard established by International Organization of Standardization, Kerboros protocol (which has run to the fifth edition) brought forward by MIT, and so on, and these works has brought out wide infection. Meanwhile, there is a very important technology is secret sharing, whose purpose is to prevent secret from too centralizing by dividing it into several pieces. Since 1979, Shamir advanced this idea, the theory of secret sharing and threshold scheme achieved unprecedented development and application. Its implementation arise people's attention.Threshold mechanism and forward safety mechanism is two kinds of important method about key safekeeping of security. Threshold mechanism means that the key was taken care of by many members together instead of taken by one person, through secret sharing scheme. Therefore even if individual or the minority member's secret share divulges, there will be no affection to the key security of overall system.Forward safety mechanism then partitions the overall system life into certain times, each time has its corresponding key. Even if the aggressor has grasped the key of some time, he is still unable to obtain the key before this time. In our actual operating process, the private key may be stored in the hardware medium (for example the intelligent IC card) through encryption, but the safety only having the hardware medium is insufficient, it cannot prevent the IC card possessor from using the smart card evilly. Therefore, sometimes we need to control some essential key by multi- people together, each person owns one part of key information, only when a certain number of persona provide their secret information which oneself grasps at the same time, the key which...