ABSTRACT
This chapter focuses on constructing a secure threshold Attribute-Based Signcryption (tABSC) scheme with a constant number of pairing evaluations. It reviews the necessary mathematical and cryptographic background. The chapter presents tABSC scheme with a constant number of pairings and its security proofs. It provides an efficient and secure tABSC scheme with constant number of pairings, by employing the threshold Attribute-Based Signature (ABS) scheme as a building block. Attribute-Based Encryption (ABE) has become an elegant solution to the problem of providing fine grained access control over encrypted data. In this public key encryption, public keys are attributes, and private keys and ciphertexts are generated based on some policies over attributes. tABSC schemes remain attractive for many applications such as body area network security, and authenticated key agreement.
