Registered attribute-based encryption with reliable outsourced decryption based on blockchain

Abstract

Decentralized data sovereignty and secure data exchange are regarded as foundational pillars of the new era. Attribute-based encryption (ABE) is a promising solution that enables fine-grained access control in data sharing. Recently, Hohenberger et al. (Eurocrypt 2023) introduced registered ABE (RABE) to eliminate trusted authority and gain decentralization. Users generate their own public and secret keys and then register their keys and attributes with a transparent key curator. However, RABE still suffers from heavy decryption overhead. A natural approach to address this issue is to outsource decryption to a decryption cloud server (DCS). In this work, we propose the first auditable RABE scheme with reliable outsourced decryption (ORABE) based on blockchain. First, we achieve verifiability of transform ciphertext via a verifiable tag mechanism. Then, the exemptibility, which ensures that the DCS escapes false accusations, is guaranteed by zero knowledge fraud proof under the optimistic assumption. Additionally, our system achieves fairness and auditability to protect the interests of all parties through blockchain. Finally, we give concrete security and theoretical analysis and evaluate our scheme on Ethereum to demonstrate feasibility and efficiency.

Graphical abstract

Keywords

registered attribute-based encryption / outsourced decryption / blockchain / non-interactive zero knowledge proof

References

[1] Gan W, Ye Z, Wan S, Yu P S. Web 3.0: the future of internet. In: Proceedings of the ACM Web Conference. 2023, 1266−1275

[2] Bethencourt J, Sahai A, Waters B. Ciphertext-policy attribute-based encryption. In: Proceedings of 2007 IEEE Symposium on Security and Privacy. 2007, 321−334

[3] Lewko A, Waters B. Decentralizing attribute-based encryption. In: Proceedings of the 30th Annual International Conference on the Theory and Applications of Cryptographic Techniques on Advances in Cryptology. 2011, 568−588

[4] Hohenberger S, Lu G, Waters B, Wu D J. Registered attribute-based encryption. In: Proceedings of the 42nd Annual International Conference on the Theory and Applications of Cryptographic Techniques on Advances in Cryptology. 2023, 511−542

[5] Garg R, Lu G, Waters B, Wu D J. Reducing the CRS size in registered ABE systems. In: Proceedings of the 44th Annual International Cryptology Conference on Advances in Cryptology. 2024, 143−177

[6] Freitag C, Waters B, Wu D J. How to use (plain) witness encryption: registered ABE, flexible broadcast, and more. In: Proceedings of the 43rd Annual International Cryptology Conference on Advances in Cryptology. 2023, 498−531

[7] Zhu Z, Zhang K, Gong J, Qian H. Registered ABE via predicate encodings. In: Proceedings of the 29th International Conference on the Theory and Application of Cryptology and Information Security on Advances in Cryptology. 2023, 66−97

[8] Attrapadung N, Tomida J. A modular approach to registered ABE for unbounded predicates. In: Proceedings of the 44th Annual International Cryptology Conference on Advances in Cryptology. 2024, 280−316

[9] Weng W, Li J, Zhang Y, Lu Y, Shen J, Han J. Efficient registered attribute based access control with same sub-policies in mobile cloud computing. IEEE Transactions on Mobile Computing, 2025

[10] Li J, Chen S, Lu Y, Ning J, Shen J, Zhang Y. Revocable registered attribute-based encryption with user deregistration. IEEE Internet of Things Journal, 2025, 12(15): 31526–31535

[11] Goyal V, Pandey O, Sahai A, Waters B. Attribute-based encryption for fine-grained access control of encrypted data. In: Proceedings of the 13th ACM Conference on Computer and Communications Security. 2006, 89−98

[12] Waters B. Ciphertext-policy attribute-based encryption: an expressive, efficient, and provably secure realization. In: Proceedings of the 14th International Conference on Practice and Theory in Public Key Cryptography. 2011, 53−70

[13] Green M, Hohenberger S, Waters B. Outsourcing the decryption of ABE ciphertexts. In: Proceedings of the 20th USENIX Conference on Security. 2011

[14] ElGamal T . A public key cryptosystem and a signature scheme based on discrete logarithms. IEEE Transactions on Information Theory, 1985, 31( 4): 469–472

[15] Lai J, Deng R H, Guan C, Weng J . Attribute-based encryption with verifiable outsourced decryption. IEEE Transactions on Information Forensics and Security, 2013, 8( 8): 1343–1354

[16] Li J, Huang X, Li J, Chen X, Xiang Y . Securely outsourcing attribute-based encryption with checkability. IEEE Transactions on Parallel and Distributed Systems, 2014, 25( 8): 2201–2210

[17] Qin B, Deng R H, Liu S, Ma S . Attribute-based encryption with efficient verifiable outsourced decryption. IEEE Transactions on Information Forensics and Security, 2015, 10( 7): 1384–1393

[18] Lin S, Zhang R, Ma H, Wang M . Revisiting attribute-based encryption with verifiable outsourced decryption. IEEE Transactions on Information Forensics and Security, 2015, 10( 10): 2119–2130

[19] Miao Y, Li F, Li X, Ning J, Li H, Choo K K R, Deng R H . Verifiable outsourced attribute-based encryption scheme for cloud-assisted mobile E-health system. IEEE Transactions on Dependable and Secure Computing, 2024, 21( 4): 1845–1862

[20] Xu J, Wen Q, Li W, Jin Z . Circuit ciphertext-policy attribute-based hybrid encryption with verifiable delegation in cloud computing. IEEE Transactions on Parallel and Distributed Systems, 2016, 27( 1): 119–129

[21] Li J, Wang Y, Zhang Y, Han J . Full verifiability for outsourced decryption in attribute based encryption. IEEE Transactions on Services Computing, 2020, 13( 3): 478–487

[22] Cui H, Wan Z, Wei X, Nepal S, Yi X . Pay as you decrypt: decryption outsourcing for functional encryption using blockchain. IEEE Transactions on Information Forensics and Security, 2020, 15: 3227–3238

[23] Nakamoto S. Bitcoin: a peer-to-peer electronic cash system. 2008

[24] Wood G. Ethereum: a secure decentralised generalised transaction ledger. Ethereum Project Yellow Paper, 2014

[25] Ge C, Liu Z, Susilo W, Fang L, Wang H . Attribute-based encryption with reliable outsourced decryption in cloud computing using smart contract. IEEE Transactions on Dependable and Secure Computing, 2024, 21( 2): 937–948

[26] Sahai A, Waters B. Fuzzy identity-based encryption. In: Proceedings of the 24th Annual International Conference on the Theory and Applications of Cryptographic Techniques on Advances in Cryptology. 2005, 457−473

[27] Ma H, Zhang R, Wan Z, Lu Y, Lin S . Verifiable and exculpable outsourced attribute-based encryption for access control in cloud computing. IEEE Transactions on Dependable and Secure Computing, 2017, 14( 6): 679–692

[28] Datta P, Pal T. Registration-based functional encryption. Cryptology ePrint Archive, 2023, 457

[29] Datta P, Pal T, Yamada S. Registered FE beyond predicates: (attribute-based) linear functions and more. In: Proceedings of the 30th International Conference on the Theory and Application of Cryptology and Information Security on Advances in Cryptology. 2024, 65−104

[30] Francati D, Friolo D, Maitra M, Malavolta G, Rahimi A, Venturi D. Registered (inner-product) functional encryption. In: Proceedings of the 29th International Conference on the Theory and Application of Cryptology and Information Security on Advances in Cryptology. 2023, 98−133

[31] Chen S, Li J, Zhang Y, Han J . Efficient revocable attribute-based encryption with verifiable data integrity. IEEE Internet of Things Journal, 2024, 11( 6): 10441–10451

[32] Fiat A, Shamir A. How to prove yourself: practical solutions to identification and signature problems. In: Odlyzko A M, ed. Advances in Cryptology - CRYPTO ’86. Berlin, Heidelberg: Springer, 1987, 186−194

RIGHTS & PERMISSIONS

Higher Education Press