Pairing-based strong key-insulated signature scheme

All public key cryptosystems are secure based on the assumption that user's private keys are absolutely secure. Exposure of this private key may lead to failure of the communication system. To diminish the damage of private key exposure in public key cryptosystem, key-insulation mechanism was introduced. In key-insulated cryptosystems, user can update his private key with helper assistance from time to time. Identity-based cryptosystem avoids the heavy certificate management problems in traditional public key cryptosystem. To improve the efficiency and to resist the problem of private key exposure in identity-based signature schemes, we present an efficient key insulated signature scheme in ID-based setting using bilinear pairings over elliptic curves. The proposed scheme is unforgeable and achieves strong key insulation property with secure key updates under the hardness of the computational Diffie-Hellman problem. The proposed scheme is more efficient than the existing schemes.