In this paper, the security technology of ad hoc networks is studied.To improve the previous multi-receiver signcryption schemes, an ID-based multi-message and multi-receiver signcryption scheme for rekeying in ad hoc networks is proposed.In this scheme, a sender can simultaneously signcrypt n messeges for n receivers, and a receiver can unsigncrypt the ciphertext to get his message with his own private key.An analysis of this scheme indicates that it achieves authenticity and confidentiality in the random oracle model while being of lower computation and communication overhead.Finally, for the application of our scheme in ad hoc, a threshold key updating protocol for ad hoc networks is given. In this paper, the security technology of ad hoc networks is studied. To improve the previous multi-receiver signaling protocols, an ID-based multi-message and multi-receiver signaling scheme for rekeying in ad hoc networks is proposed. In this scheme, a sender can simultaneously signcrypt n messeges for n receivers, and a receiver unsigncrypt the ciphertext to get his message with his own private key. An analysis of this scheme indicates that it achieves authenticity and confidentiality in the random oracle model while being of lower computation and communication overhead. Finally, for the application of our scheme in ad hoc, a threshold key updating protocol for ad hoc networks is given.