An IND-CCA2 Secure Key-Policy Attribute-Based Key Encapsulation Scheme

Abstract

Attribute-based encryption has become an active topic within the last few years, which can be regarded as a special identity-based encryption integrated with flexible access structure. In this paper, we extend the concept of key encapsulation mechanisms to the attribute-based setting and formalize the definition and security model for key policy attribute-based key encapsulation mechanism (KPAB-KEM). In KP-AB-KEM, each ciphertext is labeled by the encryptor with a set of descriptive attributes, and each private key is associated with an access structure that specifies which type of ciphertexts the key can decrypt. We also give a construction of KP-AB-KEM and prove the proposed KP-AB-KEM scheme to be IND-CCA2 secure in the standard model under the decisional bilinear Diffie-Hellman assumption.