Attribute-Based Encryption with Key Cloning Protection

In this work, we consider the problem of key cloning in attribute-based encryption schemes. We introduce a new type of attribute-based encryption scheme, called token-based attributebased encryption, that provides strong deterrence for key cloning, in the sense that delegation of keys reveals some personal information about the user. We formalize the security requirements for such a scheme in terms of indistinguishability of the ciphertexts and two new security requirements which we call uncloneability and privacy-preserving. We construct a privacy-preserving uncloneable token-based attribute-based encryption scheme based on Cheung and Newport’s ciphertext-policy attribute-based encryption scheme and prove the scheme satisfies the above three security requirements. We discuss our results and show directions for future research.