Abstract. Digital Signatures emerge naturally from Public-Key Encryption based on trapdoor permutations, and the “duality” of the two primitives was noted as early as Diffie-Hellman’s seminal work. The present work is centered around the crucial observation that two well known cryptographic primitives whose connection has not been noticed so far in the literature enjoy an analogous “duality.” The primitives are Group Signature Schemes and Public-Key Traitor Tracing. Based on the observed “duality,” we introduce new design methodologies for group signatures that convert a traitor tracing scheme into its “dual” group signature scheme. Our first methodology applies to generic public-key traitor tracing schemes. We demonstrate its power by applying it to the Boneh-Franklin scheme, and obtaining its “dual” group signature. This scheme is the first provably secure group signature scheme whose signature size is not proportional to the size of the group and is based onl...