This paper proposes an identity-based encryption scheme with the help of bilinear pairings, where the identity information of a user functions as the user＇s public key. The advantage of an identity-based public key system is that it can avoid public key certificates and certificate management. Our identity-based encryption scheme enjoys short ciphertexts and provable security against chosen-ciphertext attack （CCA）.
Leakage of the private key has become a serious problem of menacing the cryptosystem security. To reduce the underlying danger induced by private key leakage, Dodis et al.(2003) proposed the first key-insulated signature scheme. To handle issues concerning the private key leakage in certificateless signature schemes, we devise the first certificateless key-insulated signature scheme. Our scheme applies the key-insulated mechanism to certificateless cryptography, one with neither certificate nor key escrow. We incorporate Waters (2005)’s signature scheme, Paterson and Schuldt (2006)’s identity-based signature scheme, and Liu et al.(2007)’s certificateless signature scheme to obtain a certificateless key-insulated signature scheme. Our scheme has two desirable properties. First, its security can be proved under the non-pairing-based generalized bilinear Diffie-Hellman (NGBDH) conjecture, without utilizing the random oracle model; second, it solves the key escrow problem in identity-based key-insulated signatures.
Zhong-mei WANXue-jia LAIJian WENGSheng-li LIUYu LONGXuan HONG
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 ineffcient scheme. Therefore it is desirable to devise an effcient 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 effcient and the signatures are short. The scheme is provably secure based on the diffculty of computational Diffe-Hellman(CDH) problem in the standard model.
In proxy signature schemes,the proxy signer B is permitted to produce a signature on behalf of the original signer A. However,exposure of proxy signing keys can be the most devastating attack on a proxy signature scheme since any adversary can sign messages on behalf of the proxy signer. In this paper,we applied Dodis,et al.’s key-insulation mechanism and proposed an Identity-Based (ID-based) Key-Insulated Proxy Signature (IBKIPS) scheme with secure key-updates. The proposed scheme is strong key-insulated and perfectly key-insulated. Our scheme also supports unbounded period numbers and random-access key-updates.
Wan ZhongmeiLai XuejiaWeng JianLiu ShengliHong Xuan
