Inter-domain Identity-based Proxy Re-encryption

Proxy re-encryption is a cryptographic primitive developed to delegate the decryption right from one party (the delegator) to another (the delegatee). So far, no particular research efforts have been devoted to this primitive in the inter-domain identity-based setting, where the delegator and the delegatee are registered at different domains. In this paper we analyze the trust relationships and possible threats to the plaintexts of both the delegator and the delegatee in this setting, and provide game-based semantic security definitions. We propose a new inter-domain identity-based proxy re-encryption scheme and prove its security in our security model. An interesting property of our scheme is that, to achieve the chosen plaintext security for the delegator, the delegatee's IBE only needs to be one-way.