IACR News item: 13 August 2014
zhen Liu, Duncan S. Wong
ePrint ReportWhen compared with the latest traceable CP-ABE schemes, this new scheme achieves the same efficiency level, enjoying the sub-linear overhead of $O(\\sqrt{N})$, where $N$ is the number of users in the system, and attains the same security level, namely, the fully collusion-resistant traceability against policy-specific decryption blackbox, which is proven against selective adversaries in the standard model.
The scheme also supports large attribute universe, and attributes do not need to be pre-specified during the system setup. It is highly expressive and can take any monotonic access structures as ciphertext policies.
We also present the analogous results in the Key-Policy Attribute-Based Encryption (KP-ABE) setting, where users\' description keys are described by access policies and ciphertexts are associated with attributes.
We construct the first practical KP-ABE which possesses the three important properties: (1) blackbox traceability, (2) revocation, and (3) supporting large universe.
The scheme is highly expressive and can take any monotonic access structures as key policies,
and is efficient, namely, enjoys the sub-linear overhead of $O(\\sqrt{N})$ while supporting fully collusion-resistant blackbox traceability and revocation, and does not need to pre-specify the attributes during the system setup.
The scheme is proven selectively secure in the standard model.
Additional news items may be found on the IACR news page.