Research On Identity Based Public Key Management Scheme

In traditional Public Key Infrastructure(PKI),the system uses certificate to ensure the relation between public key and relative private key.Whereas,there are some problems,such as expansibility and certificate management,in PKI.For simplifing certificate management in PKI,Shamir proposed a public key system based on identity. In cipher svstem based on identity the certificate authentication is needless,but some problems has not been settled,such as key trusteeship and key revocation.The paper took elaborate research on these problems in cipher system based on identity,proposed two new schemes.The major works as follows:First,searched existing schemes for settling key trusteeship,and proposed a key management scheme based on(t,n) threshold.The scheme contains TA(Turst Authority).Proved the scheme could settle key trusteeship.In the scheme,key revocation is a implicit revocation;Second,based on scheme one,proposed a key management scheme without TA, called scheme two.The scheme optimized some lacks in scheme one,proposed a new user key pair and encryption & decryption,in which key revocation is explicit revocation;Three,used SK-IBE safe model and Fujisaki-Okamoto mix commutation,proved using designed new cipher algorithm could resist chosen ciphertext attack in scheme two.Four,In allusion to existed efficiency bottleneck problem in scheme two,based on scheme two,proposed a tree structure transformation to settle efficiency in single key generation.