Identity-Based Threshold Key-Insulated Proxy Signature in the Standard Model

Abstract

Loss of secret keys is the deadly attack in public key cryptosystems. We present an identity-based threhold key-insulated proxy signature (IBTKIPS) scheme to settle the problem of key exposure in the identity-based proxy signature system. The proposed IBTKIPS scheme is secure in the standard model. In the IBTKIPS scheme, we use at least k out of n helper keys to refresh the temporary secret keys. The IBTKIPS scheme is more flexible and securer than the identity-based proxy signature scheme.