Abstract: An identity-based public key pre-distribution scheme was proposed by taking advantage of combined public key framework and portable trusted platform module(PTPM) to protect keys.To reduce the communication overhead in the process of Ad Hoc network key management,two methods were adopted,one was that private key generation(PKG) distributed a subset of master key for node,another one was that key could be updated by time changing.In the scheme,PTPM was a basic secure hardware to protect the pre-assigned key and the node.Compared with similar schemes,this scheme needed much less communication overhead to accomplish key update service.Experimental results of the prototype system show that the scheme can provide fast key management service with the secure support based on hardware for Ad Hoc network.Meanwhile,an application paradigm of the key management based on PTPM is showed in the paper.