Abstract
(Fully) homomorphic encryption ((F)HE) allows users to publicly evaluate circuits on encrypted data. Although public homomorphic evaluation property has various applications, (F)HE cannot achieve security against chosen ciphertext attacks (CCA2) due to its nature. To achieve both the CCA2 security and homomorphic evaluation property, Emura et al. (PKC 2013) introduced keyed-homomorphic public key encryption (KH-PKE) and formalized its security denoted by \(\mathsf {KH}\text {-}\mathsf {CCA}\) security. KH-PKE has a homomorphic evaluation key that enables users to perform homomorphic operations. Intuitively, KH-PKE achieves the CCA2 security unless adversaries have a homomorphic evaluation key. Although Lai et al. (PKC 2016) proposed the first keyed-fully homomorphic encryption (keyed-FHE) scheme, its security relies on the indistinguishability obfuscation (\(\mathsf {iO}\)), and this scheme satisfies a weak variant of \(\mathsf {KH}\text {-}\mathsf {CCA}\) security. Here, we propose a generic construction of a \(\mathsf {KH}\text {-}\mathsf {CCA}\) secure keyed-FHE scheme from an FHE scheme secure against non-adaptive chosen ciphertext attack (CCA1) and a strong dual-system simulation-sound non-interactive zero-knowledge (strong DSS-NIZK) argument system by using the Naor-Yung paradigm. We show that there are a strong DSS-NIZK and an IND-CCA1 secure FHE scheme that are suitable for our generic construction. This shows that there exists a keyed-FHE scheme from simpler primitives than iO.
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Notes
- 1.
Although Desmedt et al. [18] proposed a HE scheme with a designated evaluation called controlled HE, no CCA security was considered unlike the KH-PKE.
- 2.
In this paper, keyed-FHE is a public key setting.
- 3.
\((x,\beta )\) is correct for a language \(\mathcal {L}(R)\) (or \(\beta \) is correct for x) if \(x \in \mathcal {L}(R) \wedge \beta = 1\), or \(x \notin \mathcal {L}(R) \wedge \beta = 0\). \((x,\beta )\) is not correct for \(\mathcal {L}(R)\) (or \(\beta \) is not correct for x) otherwise.
- 4.
Concretely, two FHE ciphertexts \(\mathsf {Enc}(\mathsf {pk}_1,\mathsf {m}_1)\) and \(\mathsf {Enc}(\mathsf {pk}_2,\mathsf {m}_2)\) can be transformed into a ciphertext \(\mathsf {Enc}(\mathsf {pk}_1,\mathsf {Enc}(\mathsf {pk}_2,\mathsf {m}_1 - \mathsf {m}_2))\). If for two FHE ciphertexts \(\mathsf {Enc}(\mathsf {pk}_1,\mathsf {m}_1;r_1)\) and \(\mathsf {Enc}(\mathsf {pk}_2,\mathsf {m}_2;r_2)\), \((\mathsf {m},r_1,r_2)\) where \(\mathsf {m}= \mathsf {m}_1 = \mathsf {m}_2\) is a witness of the Naor-Yung language, then \(\mathsf {Enc}(\mathsf {pk}_1,\mathsf {Enc}(\mathsf {pk}_2,\mathsf {m}_1 - \mathsf {m}_2))\) is a statement in \(L_H\).
References
Barak, B., et al.: On the (Im)possibility of obfuscating programs. In: Kilian, J. (ed.) CRYPTO 2001. LNCS, vol. 2139, pp. 1–18. Springer, Heidelberg (2001). https://doi.org/10.1007/3-540-44647-8_1
Benhamouda, F., Blazy, O., Ducas, L., Quach, W.: Hash proof systems over lattices revisited. In: Abdalla, M., Dahab, R. (eds.) PKC 2018. LNCS, vol. 10770, pp. 644–674. Springer, Cham (2018). https://doi.org/10.1007/978-3-319-76581-5_22
Bitansky, N., et al.: The hunting of the SNARK. J. Cryptol. 30(4), 989–1066 (2017)
Bitansky, N., Canetti, R., Chiesa, A., Tromer, E.: Recursive composition and bootstrapping for SNARKS and proof-carrying data. In: STOC. ACM (2013)
Brakerski, Z.: Fully homomorphic encryption without modulus switching from classical GapSVP. In: Safavi-Naini, R., Canetti, R. (eds.) CRYPTO 2012. LNCS, vol. 7417, pp. 868–886. Springer, Heidelberg (2012). https://doi.org/10.1007/978-3-642-32009-5_50
Brakerski, Z., Cash, D., Tsabary, R., Wee, H.: Targeted homomorphic attribute-based encryption. In: TCC (B2), pp. 330–360 (2016)
Brakerski, Z., Gentry, C., Vaikuntanathan, V.: (Leveled) fully homomorphic encryption without bootstrapping. In: ITCS, pp. 309–325. ACM (2012)
Brakerski, Z., Vaikuntanathan, V.: Efficient fully homomorphic encryption from (standard) LWE. In: FOCS, pp. 97–106. IEEE Computer Society (2011)
Brakerski, Z., Vaikuntanathan, V.: Fully homomorphic encryption from ring-LWE and security for key dependent messages. In: Rogaway, P. (ed.) CRYPTO 2011. LNCS, vol. 6841, pp. 505–524. Springer, Heidelberg (2011). https://doi.org/10.1007/978-3-642-22792-9_29
Brakerski, Z., Vaikuntanathan, V.: Lattice-based FHE as secure as PKE. In: ITCS, pp. 1–12. ACM (2014)
Canetti, R., Raghuraman, S., Richelson, S., Vaikuntanathan, V.: Chosen-ciphertext secure fully homomorphic encryption. In: Public Key Cryptography, pp. 213–240 (2017)
Chase, M., et al.: Post-quantum zero-knowledge and signatures from symmetric-key primitives. In: CCS, pp. 1825–1842. ACM (2017)
Cheon, J.H., et al.: Batch fully homomorphic encryption over the integers. In: Johansson, T., Nguyen, P.Q. (eds.) EUROCRYPT 2013. LNCS, vol. 7881, pp. 315–335. Springer, Heidelberg (2013). https://doi.org/10.1007/978-3-642-38348-9_20
Chiesa, A., Manohar, P., Spooner, N.: Succinct arguments in the quantum random oracle model. In: Hofheinz, D., Rosen, A. (eds.) TCC 2019. LNCS, vol. 11892, pp. 1–29. Springer, Cham (2019). https://doi.org/10.1007/978-3-030-36033-7_1
Clear, M., McGoldrick, C.: Multi-identity and multi-key leveled FHE from learning with errors. In: Gennaro, R., Robshaw, M. (eds.) CRYPTO 2015. LNCS, vol. 9216, pp. 630–656. Springer, Heidelberg (2015). https://doi.org/10.1007/978-3-662-48000-7_31
Coron, J.-S., Mandal, A., Naccache, D., Tibouchi, M.: Fully homomorphic encryption over the integers with shorter public keys. In: Rogaway, P. (ed.) CRYPTO 2011. LNCS, vol. 6841, pp. 487–504. Springer, Heidelberg (2011). https://doi.org/10.1007/978-3-642-22792-9_28
Cramer, R., Shoup, V.: Universal hash proofs and a paradigm for adaptive chosen ciphertext secure public-key encryption. In: EUROCRYPT, pp. 45–64 (2002)
Desmedt, Y., Iovino, V., Persiano, G., Visconti, I.: Controlled homomorphic encryption: definition and construction. In: Brenner, M., et al. (eds.) FC 2017. LNCS, vol. 10323, pp. 107–129. Springer, Cham (2017). https://doi.org/10.1007/978-3-319-70278-0_7
van Dijk, M., Gentry, C., Halevi, S., Vaikuntanathan, V.: Fully homomorphic encryption over the integers. In: Gilbert, H. (ed.) EUROCRYPT 2010. LNCS, vol. 6110, pp. 24–43. Springer, Heidelberg (2010). https://doi.org/10.1007/978-3-642-13190-5_2
Emura, K.: On the security of keyed-homomorphic PKE: preventing key recovery attacks and ciphertext validity attacks. IEICE Trans. Fundam. Electron. Commun. Comput. Sci. 104-A(1), 310–314 (2021)
Emura, K., Hanaoka, G., Nuida, K., Ohtake, G., Matsuda, T., Yamada, S.: Chosen ciphertext secure keyed-homomorphic public-key cryptosystems. Des. Codes Crypt. 86(8), 1623–1683 (2017). https://doi.org/10.1007/s10623-017-0417-6
Emura, K., Hanaoka, G., Ohtake, G., Matsuda, T., Yamada, S.: Chosen ciphertext secure keyed-homomorphic public-key encryption. In: Kurosawa, K., Hanaoka, G. (eds.) PKC 2013. LNCS, vol. 7778, pp. 32–50. Springer, Heidelberg (2013). https://doi.org/10.1007/978-3-642-36362-7_3
Faust, S., Kohlweiss, M., Marson, G.A., Venturi, D.: On the non-malleability of the fiat-shamir transform. In: Galbraith, S., Nandi, M. (eds.) INDOCRYPT 2012. LNCS, vol. 7668, pp. 60–79. Springer, Heidelberg (2012). https://doi.org/10.1007/978-3-642-34931-7_5
Gentry, C.: Fully homomorphic encryption using ideal lattices. In: STOC, pp. 169–178. ACM (2009)
Gentry, C., Sahai, A., Waters, B.: Homomorphic encryption from learning with errors: conceptually-simpler, asymptotically-faster, attribute-based. In: Canetti, R., Garay, J.A. (eds.) CRYPTO 2013. LNCS, vol. 8042, pp. 75–92. Springer, Heidelberg (2013). https://doi.org/10.1007/978-3-642-40041-4_5
Giacomelli, I., Madsen, J., Orlandi, C.: ZKBoo: faster zero-knowledge for boolean circuits. In: USENIX Security Symposium, pp. 1069–1083. USENIX Association (2016)
Jutla, C., Roy, A.: Relatively-sound NIZKs and password-based key-exchange. In: Fischlin, M., Buchmann, J., Manulis, M. (eds.) PKC 2012. LNCS, vol. 7293, pp. 485–503. Springer, Heidelberg (2012). https://doi.org/10.1007/978-3-642-30057-8_29
Jutla, C.S., Roy, A.: Switching lemma for bilinear tests and constant-size NIZK proofs for linear subspaces. In: Garay, J.A., Gennaro, R. (eds.) CRYPTO 2014. LNCS, vol. 8617, pp. 295–312. Springer, Heidelberg (2014). https://doi.org/10.1007/978-3-662-44381-1_17
Jutla, C.S., Roy, A.: Dual-system simulation-soundness with applications to UC-PAKE and more. In: Iwata, T., Cheon, J.H. (eds.) ASIACRYPT 2015. LNCS, vol. 9452, pp. 630–655. Springer, Heidelberg (2015). https://doi.org/10.1007/978-3-662-48797-6_26
Lai, J., Deng, R.H., Ma, C., Sakurai, K., Weng, J.: CCA-secure keyed-fully homomorphic encryption. In: Cheng, C.-M., Chung, K.-M., Persiano, G., Yang, B.-Y. (eds.) PKC 2016. LNCS, vol. 9614, pp. 70–98. Springer, Heidelberg (2016). https://doi.org/10.1007/978-3-662-49384-7_4
Libert, B., Nguyen, K., Passelègue, A., Titiu, R.: Simulation-sound arguments for LWE and applications to KDM-CCA2 security. In: Moriai, S., Wang, H. (eds.) ASIACRYPT 2020. LNCS, vol. 12491, pp. 128–158. Springer, Cham (2020). https://doi.org/10.1007/978-3-030-64837-4_5
Libert, B., Peters, T., Joye, M., Yung, M.: Non-malleability from malleability: simulation-sound quasi-adaptive NIZK Proofs and CCA2-Secure encryption from homomorphic signatures. In: Nguyen, P.Q., Oswald, E. (eds.) EUROCRYPT 2014. LNCS, vol. 8441, pp. 514–532. Springer, Heidelberg (2014). https://doi.org/10.1007/978-3-642-55220-5_29
Loftus, J., May, A., Smart, N.P., Vercauteren, F.: On CCA-secure somewhat homomorphic encryption. In: Miri, A., Vaudenay, S. (eds.) SAC 2011. LNCS, vol. 7118, pp. 55–72. Springer, Heidelberg (2012). https://doi.org/10.1007/978-3-642-28496-0_4
López-Alt, A., Tromer, E., Vaikuntanathan, V.: On-the-fly multiparty computation on the cloud via multikey fully homomorphic encryption. In: STOC, pp. 1219–1234. ACM (2012)
Maeda, Y., Nuida, K.: Chosen ciphertext secure keyed two-level homomorphic encryption. IACR Cryptol. ePrint Arch. 2021, 722 (2021). https://eprint.iacr.org/2021/722
Naor, M., Yung, M.: Public-key cryptosystems provably secure against chosen ciphertext attacks. In: STOC, pp. 427–437. ACM (1990)
Sahai, A.: Non-malleable non-interactive zero knowledge and adaptive chosen-ciphertext security. In: FOCS, pp. 543–553. IEEE Computer Society (1999)
Acknowledgments
This work was supported by JST CREST Grant Numbers JPMJCR19F6 and JPMJCR2113, Japan, and JSPS KAKENHI Grant Number 19K20267. We would like to thank Prof. Thomas Peters since he gave us insightful suggestion to instantiate our keyed-FHE scheme in the standard model.
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Sato, S., Emura, K., Takayasu, A. (2022). Keyed-Fully Homomorphic Encryption Without Indistinguishability Obfuscation. In: Ateniese, G., Venturi, D. (eds) Applied Cryptography and Network Security. ACNS 2022. Lecture Notes in Computer Science, vol 13269. Springer, Cham. https://doi.org/10.1007/978-3-031-09234-3_1
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