Time Constraint Delegation for P2P Data Decryption

Large amount of digital content would be stored safely in peer-to-peer network, with encrypted format. Being requested, a cipher text is downloaded from certain peer and decrypted by a delegated decryptor to obtain the clear text. Observing the need for this new kind of delegation decryption service, we propose a novel time constraint delegation scheme for decrypting p2p data in this paper. The new features of the delegation scheme are that: it uses a flexible secure mobile agent solution without designated delegation server; the time constraint conditional parameter is clearly bound with the protocols; and the computation complexity is greatly reduced by replacing public key computation with hash function. We elaborate the protocol design as well as its security, extensions and properties. Potential applications in content delivery network and pervasive computing scenarios are depicted.