Improved VLR Group Signature Based on DTDH Assumption

In VLR (verifier-local revocation) group signatures, revocation messages are only sent to signature verifiers (as opposed to both signers and verifiers). Consequently there is no need to contact individual signers when some user is revoked. Since signers have no load, the VLR group signature schemes are suitable for mobile environments. To meet the requirement of speediness in mobile communication, reducing computation costs and shortening signature length are two requirements at the current research of VLR group signatures. Based on this idea, an improved version of Zhou’s VLR group signature is given. Compared with the original scheme, the improved scheme not only can achieve the same security level, but also has shorter signature size and lower computation costs.