Attribute Revocable Attribute-Based Encryption for Decentralized Disruption-Tolerant Military Networks

Disruption-tolerant network technologies are becoming solutions to access the confidential information or command by exploiting external storage node. It is necessary to encrypt the shared data to prevent illegal access to ciphertext by the third party. It is expected that commanders could control whether the user can decrypt the ciphertext or not. Besides, it is essential that a key authority distributing keys to users is decentralized to several authorities for avoiding the invasion from enemy. Thus, Ciphertext-Policy Attribute-Based Encryption (CP-ABE) as a suitable encryption scheme for confidential data share and transmission is attracted attention under the military environment. In CP-ABE, the secret key of a user is associated with a set of atrributes; when attributes satisfy the access structure, the ciphertext is able to be decrypted. In this paper, we propose a CP-ABE scheme which can revoke attribute immediately with no updating user's secret key for attribute revocation. In addition, the length of key and ciphertext are fixed. Furthermore the proposed scheme has been compared with other CP-ABE schemes in key size, ciphertext size to validate its efficiency.