As drone technology advances, Unmanned Aerial Vehicles (UAVs) increasingly serve as aerial relays in ground-air cooperative networks. However, their dynamic topology and resource constraints create significant security challenges during concurrent user equipment (UE) authentication. Traditional batch authentication mechanisms fail under invalid requests, causing systemic failures and inefficiency. To address this, we propose a novel certificateless aggregate signature (CLAS)-based protocol integrating group testing for rapid error detection.

1. Introduction
The proliferation of drone technology enables critical applications from disaster response to precision agriculture. In 5G-integrated Unmanned Aerial Vehicle networks, UAVs act as relays between ground UEs and infrastructure. Yet concurrent authentication requests overwhelm UAV resources, while malicious nodes trigger batch failures. Existing solutions exhibit three limitations:
- Certificate management overhead in PKI-based systems
- Key escrow risks in identity-based schemes
- Poor fault tolerance during invalid request scenarios
Our protocol innovatively combines CLAS with group testing to enable efficient batch verification and precise error localization. Key contributions include:
- Lightweight CLAS mechanism eliminating pairing operations
- Adaptive group testing for invalid request identification
- Formal security proofs under random oracle model
This approach optimizes performance for resource-constrained Unmanned Aerial Vehicle environments while maintaining robust security.
2. System and Threat Models
2.1 Network Architecture
The framework comprises four entities:
| Entity | Role |
|---|---|
| User Equipment (UE) | Authentication initiator using pseudonyms |
| Unmanned Aerial Vehicle (UAV) | Batch authenticator and relay node |
| Control Center (CC) | Pseudonym issuance and identity tracing |
| Key Generation Center (KGC) | Partial private key distribution |
2.2 Security Model
We consider two adversarial types:
- Type I: Can replace public keys but cannot access KGC master key
- Type II: Can compromise KGC but cannot replace public keys
Security is formalized through oracle queries and games:
\text{Setup: } \mathcal{C} \text{ generates } (s, P_{\text{pub}})\\
\text{Queries: } \mathcal{O}_{\text{Partial-Private}}, \mathcal{O}_{\text{Replace-PK}}\\
\text{Forgery: } \sigma^* \text{ for } (\text{PID}^*, m^*)
\end{cases} $$
3. Protocol Design
3.1 Initialization Phase
KGC and CC establish parameters on elliptic curve \(E: y^2 = x^3 + ax + b \mod p\):
&\text{Select primes } p, q \\
&\text{Set base point } P \in E \\
&\text{KGC: } s \xleftarrow{\$} \mathbb{Z}_p^*, P_{\text{pub}} = s \cdot P \\
&\text{CC: } b \xleftarrow{\$} \mathbb{Z}_p^*, T_{\text{pub}} = b \cdot P \\
&\text{UAV key: } q_{\text{UAV}} \xleftarrow{\$} \mathbb{Z}_p^*, pk_{\text{UAV}} = q_{\text{UAV}} \cdot P
\end{align*} $$
3.2 Pseudonym and Key Generation
For UE registration:
&\text{UE} \rightarrow \text{CC}: \{\text{PID}_{i,1}, \text{Key}_i\} \text{ where } \\
&\quad \text{PID}_{i,1} = t_i \cdot P, \\
&\quad \text{Key}_i = \text{RID}_i \oplus t_i \cdot T_{\text{pub}} \\
&\text{CC computes: } \text{PID}_{i,2} = H_1(\text{RID}_i \oplus b \cdot \Delta T_i, \text{PID}_{i,1}) \\
&\text{Pseudonym: } \text{PID}_i = \{\text{PID}_{i,1}, \text{PID}_{i,2}, \Delta T_i\}
\end{align*} $$
3.3 Batch Authentication
For \(n\) UEs sending requests \(\{\text{PID}_i, M_i, \sigma_i\}\):
&\text{UAV aggregates: } \\
&S_{\text{agg}} = \sum_{i=1}^n S_i, \quad U_{\text{agg}} = \{U_1, \dots, U_n\} \\
&\text{Verification: } \\
&S_{\text{agg}} \cdot P \stackrel{?}{=} \sum_{i=1}^n \left( \text{Tpk}_{\text{UE}_i} + U_i + h_{i,3} \cdot Q_i + K_i \cdot P_{\text{pub}} \right)
\end{align*} $$
where \(K_i = H_1(\text{PID}_i, R_i, P_{\text{pub}})\) and \(h_{i,3} = H_3(\text{PID}_i, M_i, \text{vpk}_i, U_i, T_i)\).
3.4 Error Detection via Group Testing
When batch verification fails, construct \(d\)-disjunct matrix \(M \in \{0,1\}^{2t \times n}\):
\text{Select } \frac{t}{d} \text{ random rows} \\
M_{i,j} = 1 \text{ for selected rows} \\
M_{i,j} = 0 \text{ otherwise}
\end{cases} $$
Detection complexity: \(O(d^2 \log(n/d))\) with:
| Method | Complexity | Constraints |
|---|---|---|
| Binary Search | \(O(d \log n)\) | No parallelization |
| d-disjunct Matrix | \(O(d^2 \log n)\) | Fixed \(d\) |
| Our Method | \(O(d^2 \log(n/d))\) | Adaptive to \(n\) |
4. Security Analysis
4.1 Formal Proofs
Under ECDLP assumption, the protocol resists both adversarial types:
&\text{Theorem 1: } \forall \text{ PPT Adv}_1, \Pr[\text{Win}_{\text{Game}_1}] \leq \epsilon_{\text{ECDLP}}\\
&\text{Theorem 2: } \forall \text{ PPT Adv}_2, \Pr[\text{Win}_{\text{Game}_2}] \leq \epsilon_{\text{ECDLP}}
\end{align*} $$
Tamarin verification confirms mutual authentication properties:
lemma UAV_auth_UE:
"All UE UAV #i.
Auth_UAV(UAV) & Auth_UE(UE) @ #i ==>
(Ex #j. j < i & Request(UE) @ j)"
4.2 Security Properties
- Mutual Authentication: Verified via signatures:
$$S_i \cdot P = \text{Tpk}_{\text{UE}_i} + U_i + h_{i,3} \cdot Q_i + K_i \cdot P_{\text{pub}}$$
- Anonymity: Pseudonyms prevent identity leakage
- Traceability: CC recovers RID via \(H_1(\text{PID}_{i,2} \oplus b \cdot \Delta T_i)\)
- Replay Attack Resistance: Timestamp validation
5. Performance Evaluation
5.1 Computational Overhead
Comparison of cryptographic operations (ms):
| Scheme | Single Sign | Single Verify | Batch Verify (n) |
|---|---|---|---|
| Yan et al. | 2.69 | 8.99 | 4.06n + 1.80 |
| Maurya et al. | 4.93 | 8.53 | 8.53n + 1.80 |
| Dwivedi et al. | 3.64 | 12.59 | 3.66n + 9.00 |
| Ours | 0.88 | 5.42 | 3.63n + 1.77 |
Our CLAS implementation reduces signing cost by 67% versus best alternatives.
5.2 Communication Efficiency
Message size comparison (bytes):
| Component | Yan et al. | Cui et al. | Ours |
|---|---|---|---|
| Pseudonym | 64 | 64 | 60 |
| Public Key | 40 | 40 | 40 |
| Signature | 20 | 20 | 20 |
| Metadata | 304 | 304 | 288 |
| Total | 428 | 428 | 408 |
4% reduction through aggregated signature optimization.
5.3 Error Detection Efficiency
Group testing significantly outperforms alternatives:
For \(n=1000, d=5\):
- Binary search: 50 verifications
- d-disjunct matrix: 120 verifications
- Our method: 35 verifications
6. Conclusion
This work presents a novel batch authentication protocol for Unmanned Aerial Vehicle networks that addresses critical limitations in existing approaches. By integrating certificateless aggregate signatures with adaptive group testing, we achieve:
- 68% faster signature generation than state-of-the-art
- Precise invalid request identification with \(O(d^2 \log(n/d))\) complexity
- Formally provable security under ECDLP assumption
The protocol’s efficiency makes it particularly suitable for resource-constrained drone technology deployments requiring high-throughput authentication. Future work will explore integration with post-quantum cryptography for enhanced long-term security in evolving UAV ecosystems.
