We introduce an efficient Key-Policy Attribute-Based Encryption (KP-ABE) scheme in prime order groups. Our scheme is semi-adaptively secure under the decisional linear assumption and supports a large universe of attributes and multi-use of attributes. Those properties are critical for real applications of KP-ABE schemes since they enable an efficient and flexible access control. Prior to our work, existing KP-ABE schemes with short ciphertexts were in composite order groups or utilized either

more »

... al Pairing Vector Spaces (DPVS) or Dual System Groups (DSG) in prime order groups. However, those techniques brought an efficiency loss. In this work, we utilize a nested dual system encryption which is a variant of Waters' dual system encryption (Crypto' 09) to achieve semi-adaptively secure KP-ABE. As a result, we obtain a new scheme having better efficiency compared to existing schemes while it keeps a semi-adaptive security under the standard assumption. We implement our scheme and compare its efficiency with the previous best work.