Digital multisignature schemes for authenticating delegates in mobile codesystems

In this paper, we motivate the need for efficient multisignature schemes in delegated mobile services. With the schemes, delegates can be identified a nd delegated accesses can be controlled. First, we give a new digital signa ture scheme with message recovery. Based on the digital signature scheme, t wo digital multisignature schemes are proposed: the parallel multisignature scheme and the serial multisignature scheme. The parallel multisignature s cheme allows each user to sign the same message separately and independentl y, and then combines all individual signatures into a multisignature, The s erial multisignature scheme allows a group of users to sign the message ser ially, and does not need to predetermine the signing order. Both multisigna ture schemes tan withstand the attacks that aim to forge the signatures or to get the private kegs of the signers.