Toward Dynamic Attribute-Based Signcryption (Poster)

This paper presents an ongoing work toward the proposal of the new concept of the attribute-based cryptosystem. In SCN2010, Gagne, Narayan, and Safavi-Naini proposed attribute-based signcryption (ABSC) with threshold structure. As in ciphertext-policy attribute-based encryption (CP-ABE), an encryptor can specify the access structure of decryptors, and as in attribute-based signature (ABS), each decryptor can verify the encryptor’s attributes. On the contrary to the access structure of decryptors, the access structure of the encryptor needs to be fixed in the setup phase. In this paper, we investigate ABSC with dynamic property, called dynamic ABSC (DABSC), where access structures of encryptor can be updated flexibly without re-issuing secret keys of users.