A PKG-managed authenticated identity-binding signature framework over Falcon with traceability

Falcon is a compact and efficient post-quantum signature scheme based on the NTRU lattice, but it follows the conventional public-key setting and does not directly support identity-to-key binding or signer traceability. In this paper, we propose IBFS, a PKG-managed and authenticated identity-binding signature framework over Falcon. In IBFS, a trusted Private Key Generator (PKG) derives Falcon-compatible NTRU signing keys for registered users and maintains an authenticated binding between user identities and public keys. Unlike pure identity-based signatures, verification uses the signer’s identity together with an authenticated public key validated against a PKG-managed repository. This framework targets managed deployments with a trusted registration backend, including IoT and edge systems. The device-side evaluation concerns signature verification on an Android smartphone in a server-assisted setting; it does not establish operation of the complete framework on tightly constrained IoT devices. The construction retains the efficiency advantages of Falcon-style signing, including compact short-vector signatures and FFT-accelerated arithmetic, and further introduces a deterministic, PKG-resolvable identity tag that enables resolution of verified signatures to registered identities. We establish correctness and identity-resolution consistency under authentic repository bindings, without claiming non-frameability against the PKG. On the security side, we make the trust boundaries of the managed setting explicit, including key escrow, insider compromise, malicious tracing, and repository integrity. We then give a security argument in the classical Random Oracle Model that reduces the unforgeability of the signing layer, with a concrete advantage bound, to the decisional NTRU and inhomogeneous NTRU short-preimage (NTRU-ISIS) assumptions, together with the PRF security of the key-derivation function. The analysis is restricted to classical adversaries and does not constitute a Quantum Random Oracle Model proof. We therefore position IBFS as a classical-ROM construction whose security relies on these NTRU-based assumptions and on the authenticity of the PKG-managed binding repository.