In this paper, we propose an efficient multi-authority decentralized ciphertext-policy attribute-based encryption scheme dCP-ABE-MAS for monotone access structures (MAS). Our setup is without any central authority (CA) where all authorities function entirely independently and need not even be aware of each other. The scheme makes use of the minimal authorized sets representation of MAS to encrypt messages, and hence the size of ciphertext is linear in the number of minimal authorized sets in MAS and the number of bilinear pairings is constant during decryption. We describe several networks that can use dCP-ABE-MAS to control data access from unauthorized nodes. The proposed scheme resists collusion attacks and is secure against chosen plaintext attacks in the generic bilinear group model over prime order bilinear groups.