Post-quantum group signature scheme for multi-party satellite control via CP-WOTS+ optimization

Quantum computing creates new security risks for legacy satellite communication systems, especially for Telemetry, Tracking, and Control (TT&C) links. Hash-Based Signature (HBS) schemes are seen as the safest option for Post-Quantum Cryptography (PQC) migrations, as they only depend on the collision resistance of hash functions without involving complex security assumptions. But in practice, applying current HBS standards in engineering is tough due to the trade-off between signature size and computational overhead. We solve this problem by proposing CP-WOTS+, an optimization scheme based on checkpoint pre-computation. By introducing a checkpoint mechanism to the signer, we achieved a compact signature of 1088 bytes under the w = 256 parameter set, while reducing the generation time from 7.15 to 0.45 ms (a $$15.9 \times$$ 15.9 × speedup). Building on this primitive, we designed the CP-XMSS-GS group signature scheme for multi-party satellite control. This scheme implements a centralized authorization model that offloads complexity to the ground: the satellite remains strictly stateless (storing only a 64-byte group public key) and just handles verification. Complex member management and traceability are handled by the ground administrator. Experimental results demonstrate that our scheme maintains a small signature size of 1764 bytes and ensures anonymity and traceability, and it requires zero on-orbit updates when members change. Our work provides a highly secure, lightweight post-quantum solution for resource-constrained satellite-ground links.