Iranian Society of Cryptology The ISC International Journal of Information Security 2008-2045 Articles in Press 2026 03 07 Secure Pairing-Free IBE and CP-ABE from Inner-Product Functional Encryption 241980 10.22042/isecure.2026.241980 EN Ahmad Khoureich Ka Alioune Diop University of Bambey, Senegal Journal Article The potential of Attribute-Based Encryption (ABE) in the context of IoT has driven researchers to propose pairing-free ABE schemes that are suitable for resource-constrained devices. Unfortunately, many of these schemes turned out to be insecure. This fact reinforces the view of some researchers according to which instantiating an Identity-Based Encryption (IBE) in plain Decisional Diffie-Hellman (DDH) groups is impossible. In this paper, we provide a generic Ciphertext-Policy ABE (CP-ABE) scheme supporting secret AND-gate policy using Inner-Product Functional Encryption (IPFE). We also propose an instantiation of our generic CP-ABE scheme based on the DDH assumption. From our generic CP-ABE scheme, we derive an IBE scheme by introducing the concept of Clustered Identity-Based Encryption (CIBE). Our schemes show that it is possible to construct secure IBE and ABE schemes based on the classical DDH assumption. An implementation of our CIBE in Python using the Charm framework is available on GitHub.  https://www.isecure-journal.com/article_241980_ed04c1cb7b95bae78a8f3f07edaf63f9.pdf