智慧車輛在行駛與事故過程中所產生的資料，已廣泛應用於事故鑑定、保險評估與第三方服務等不同場景，此類資料具有法律效力並涉及個人隱私，若未經妥善保存，可能遭到篡改、偽造或未授權存取，進而影響調查結果的可信度與法律效力。此外，不同應用情境對資料存取控制具有不同需求，例如，司法與監管情境通常需要由授權機關主導證據取得，而商業應用則更重視資料擁有者對資料揭露範圍的控制。因此，本論文針對車載隨意行動網路（VehicularAdHocNetwork, VANET）環境中的兩類存取控制需求，提出兩種車載數位證據保全機制。第一種為監管式機制，採用金鑰政策屬性式加密（Key-Policy Attribute-Based Encryption, KP-ABE），使可信任機構能在司法、監管與事故調查情境中執行授權控管。第二種為自主式機制，採用密文政策屬性式加密（Ciphertext-Policy Attribute-Based Encryption, CP-ABE），使資料擁有者能將存取政策直接嵌入密文中，以支援使用量型保險與連網車輛服務等商業應用。兩種機制皆結合BLS聚合簽章鏈、Merkle tree 批次聚合、混合式私有鏈與公有鏈架構，以及假名身分管理機制。透過聚合簽章，可建立可驗證的證據保管鏈；證據雜湊值則經由Merkle tree 聚合後錨定至區塊鏈，以降低鏈上儲存負擔，並維持證據完整性與外部可驗證性。此外，假名機制可在保護車輛身分隱私的同時，保留可信任機構於合法授權條件下進行身分追蹤的能力。最後，安全分析與形式化驗證結果顯示，所提出之機制能在VANET環境中實現具隱私保護與可驗證性的車載數位證據保全。

Vehicular data generated during driving and crash events are used across multiple domains including accident reconstruction, insurance assessment, and regulatory supervision, each imposing different access requirements. As these data carry legal and privacy implications, they must be preserved in a manner that prevents tampering, unauthorized access, and identity exposure while remaining verifiable by authorized parties.
This thesis proposes two complementary schemes for Vehicular Ad Hoc Network (VANET) environments. The regulated scheme uses Key-Policy Attribute-Based Encryption (KP-ABE) to support authority-enforced access control in judicial and supervisory scenarios. The owner-controlled scheme uses Ciphertext-Policy Attribute-Based Encryption (CP-ABE) to allow data owners to embed access policies directly into ciphertexts for commercial applications such as usage-based insurance and connected-vehicle services. Both schemes construct a verifiable custody chain, batch evidence hashes into Merkle trees anchored on a hybrid private-public blockchain, and employ pseudonyms to protect vehicle identity while retaining lawful traceability. Security analysis and formal verification using ProVerif confirm that the proposed schemes achieve privacy-preserving and verifiable evidence preservation in VANET environments.

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