Secure Key-Insulated Proxy Signature Scheme for Mobile Agent

It is expected that mobile agent will be widely used for electronic commerce as an important key technology. If a mobile agent may act as a proxy signer to produce signatures on behalf of the agent owner autonomously, it will increase efficiency of the agent owner. As the private key of the mobile agent is likely to be exposed, we introduce a new generic key-insulated proxy signature scheme. The scheme minimizes the damage caused by the secret key exposure. Furthermore, compared with all the previous works, the proposed scheme has 3 virtues: (1) the size of the proxy signature is constant, and independent of the number of insulated time period; (2) the size of the proxy secret key is constant q bits, without any additional overheads on the key length; (3) the scheme only has additional O(N) hash computation overheads. Finally, we support our scheme with detailed security and performance analysis.