Strong Key-Insulated Signature in the Standard Model

The only known construction of key-insulated signature （KIS） that can be proven secure in the standard model is based on the approach of using double signing. That is, the scheme requires two signatures： a signature with a master key and a signature with the signer＇s secret key. This folklore construction method leads to an inefficient scheme. Therefore it is desirable to devise an efficient KIS scheme. We present the first scheme with such a construction. Our construction derives from some variations of the Waters＇ signature scheme. It is computationally efficient and the signatures are short. The scheme is provably secure based on the difficulty of computational Diffie-Hellman （CDH） problem in the standard model.