Abstract
Traditional physical-layer secret key generation (PLSKG) schemes for the One-Time Pad (OTP) rely on a time-sharing approach, where key generation and OTP communication are separated, resulting in significant time overhead and low efficiency. To address this limitation, this letter proposes an integrated scheme, named PLSKG-OTP, that enables simultaneous key generation and data transmission by introducing random perturbations within the decision regions of the received constellation. To counter a powerful eavesdropper with prior knowledge, a composite security scheme is designed: artificial noise (AN) protects each raw key, while a cryptographic hash function (CHF) accumulates entropy across blocks, ensuring the asymptotic zero leakage security of the final encryption key. Simulations show the scheme reduces time cost to 26% of benchmarks and fulfills OTP requirements.