Forward-Secure Group Signatures from Pairings

To reduce the damage of key exposures forward secure group signature schemes have been first proposed by Song In the forward secure schemes a secret key of a group member is updated by a one way function every interval and the previous secret key is erased Thus even if a secret key is exposed the signatures produced by the secret keys of previous Intervals remain secure Since the previous forward secure group signature schemes are based on the strong RSA assumption the signatures are longer than pairing based group signatures In addition the complexity of the key update or signing/verification is O(T) where T is the total number of Intervals In this paper a forward secure group signature scheme from pairings is proposed The complexity of our key update and signing/verification is O(log T)