Aggregate and Separate of Signatures in Wireless Network

Wireless communications offer organizations and users many benefits such as portability and flexibility, but the messages transfer is limited by the power and the bandwidth. So the compactness of messages is necessary. One of the compactness is aggregate signatures, which is a single short string that convinces any verifier that for all 1 les i les n, signer S_i signs message M_i, where the n signers and n messages may all be distinct. Additionally in some especial cases, it is required to induce the single signature from the aggregate signatures. Then the separating of aggregate signatures is an interesting focus. In this paper, we first present an efficient id-based aggregate signature whose security is based on RSA assumption not on the rather new and untested assumptions related to bilinear maps. Then the notion of separation of aggregate signature is introduced and two concrete aggregate signature schemes that can be separated into single signature are presented.