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Efficient ciphertext-policy attribute-based signcryption for secure big data storage in cloud

This chapter proposes an efficient ciphertext-policy attribute-based signcryption (ECP-ABSC) for big data storage in the cloud. The ECP-ABSC scheme reduces the required number of exponentiation operations during signcryption and outsources the inflated pairing computation during the designcryption process, which, in turn, reduces the computation overhead of data owner and user. Our scheme also provides flexible access control by giving data access rights to unlimited times or a fixed number of times based on the user. This flexible access control feature increases the applicability in commercial applications. Further, we prove the desired security requirements of our scheme that include data confidentiality, signcryptor privacy, and unforgeability in security analysis. The feasibility and practicality of our scheme are provided in performance evaluation.