Abstract
Selective opening (SO) security is a security notion for public-key encryption schemes that captures security against adaptive corruptions of senders. SO security comes in chosen-plaintext (SO-CPA) and chosen-ciphertext (SO-CCA) variants, neither of which is implied by standard security notions like IND-CPA or IND-CCA security.
In this paper, we present the first SO-CCA secure encryption scheme that combines the following two properties: (1) it has a constant ciphertext expansion (i.e., ciphertexts are only larger than plaintexts by a constant factor), and (2) its security can be proven from a standard assumption. Previously, the only known SO-CCA secure encryption scheme achieving (1) was built from an ad-hoc assumption in the RSA regime.
Our construction builds upon LWE, and in particular on a new and surprisingly simple construction of compact lossy trapdoor functions (LTFs). Our LTF can be converted into an “all-but-many LTF” (or ABM-LTF), which is known to be sufficient to obtain SO-CCA security. Along the way, we fix a technical problem in that previous ABM-LTF-based construction of SO-CCA security.
This work was partially supported by ERC Project PREP-CRYPTO 724307.
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Notes
- 1.
Specifically, [32] assumes in a very strong sense that the Paillier encryption scheme is not multiplicatively homomorphic.
- 2.
Of course, in many encryption applications, hybrid encryption is possible, and thus \(x\) only needs to have enough entropy (even given \(y\)) that a symmetric encryption key can be extracted. However, in certain applications like selective-opening security, hybrid encryption does not seem to be useful, and thus a larger lossiness leads to larger messages.
- 3.
We note that while this may seem promising, it is also not possible to boost relative lossiness generically, e.g., by repetition [47].
- 4.
It is not easy to give a more quantitative comparison, since all mentioned LTF constructions offer tradeoffs regarding efficiency, relative lossiness, and compactness.
- 5.
It would seem promising to construct LTFs and ABM-LTFs from suitable homomorphic encryption schemes, and in particular from “Rate-1 FHE schemes” [13, 23], using the blueprint of [29] and [12, 38]. This may indeed lead to asymptotically compact LTFs and ABM-LTFs with large lossiness, but the corresponding constructions have an involved evaluation procedure and will require huge parameters to play out their asymptotic properties.
- 6.
It is tempting to rely on \(\textbf{e}\) (and not \(\textbf{s}\)) as a means to transport information. In particular, making \(\mathfrak {D}\) larger improves expansion (since preimages carry more information). However, at least with the arguments above, we can only argue that information about \(\textbf{s}\) (not \(\textbf{e}\)) is lost in lossy mode, i.e., with \(\textbf{A}'=\textbf{B}\textbf{D}+\textbf{E}\). Hence, making \(\mathfrak {D}\) larger improves expansion, but at the same time hurts (relative) lossiness.
- 7.
This is similar to [29], who interpret lossy encryption schemes as lossy trapdoor functions (by deriving encryption random coins deterministically from the encrypted message). Our setting is considerably simpler, however, since our final encryption scheme is deterministic.
- 8.
For instance, in (dual) Regev encryption, noise terms in ciphertexts grow with homomorphic computations. This is a problem with large factors \(M\) as above, but can be avoided by the use of a “gadget matrix” [40]. Furthermore, we are using a more economic, “batched” version of (dual) Regev encryption as with [2].
- 9.
Moreover, random tags should be injective with high probability, and it should even be possible to explain any tag (injective or not) as having been randomly sampled.
- 10.
For instance, the treatment of leakage through noise terms in [38] is quite involved, which causes also a more complex construction. In our case, the involved error terms leak little information (relative to the ABM-LTF input), and we can afford a simpler construction and analysis.
References
Alwen, J., Krenn, S., Pietrzak, K., Wichs, D.: Learning with rounding, revisited. In: Canetti, R., Garay, J.A. (eds.) CRYPTO 2013, Part I. LNCS, vol. 8042, pp. 57–74. Springer, Heidelberg (2013). https://doi.org/10.1007/978-3-642-40041-4_4
Applebaum, B., Cash, D., Peikert, C., Sahai, A.: Fast cryptographic primitives and circular-secure encryption based on hard learning problems. In: Halevi, S. (ed.) CRYPTO 2009. LNCS, vol. 5677, pp. 595–618. Springer, Heidelberg (2009). https://doi.org/10.1007/978-3-642-03356-8_35
Auerbach, B., Kiltz, E., Poettering, B., Schoenen, S.: Lossy trapdoor permutations with improved lossiness. In: Matsui, M. (ed.) CT-RSA 2019. LNCS, vol. 11405, pp. 230–250. Springer, Cham (2019). https://doi.org/10.1007/978-3-030-12612-4_12
Bellare, M., Dowsley, R., Waters, B., Yilek, S.: Standard security does not imply security against selective-opening. In: Pointcheval, D., Johansson, T. (eds.) EUROCRYPT 2012. LNCS, vol. 7237, pp. 645–662. Springer, Heidelberg (2012). https://doi.org/10.1007/978-3-642-29011-4_38
Bellare, M., Hofheinz, D., Yilek, S.: Possibility and impossibility results for encryption and commitment secure under selective opening. In: Joux, A. (ed.) EUROCRYPT 2009. LNCS, vol. 5479, pp. 1–35. Springer, Heidelberg (2009). https://doi.org/10.1007/978-3-642-01001-9_1
Bellare, M., Kiltz, E., Peikert, C., Waters, B.: Identity-based (lossy) trapdoor functions and applications. In: Pointcheval, D., Johansson, T. (eds.) EUROCRYPT 2012. LNCS, vol. 7237, pp. 228–245. Springer, Heidelberg (2012). https://doi.org/10.1007/978-3-642-29011-4_15
Bellare, M., Waters, B., Yilek, S.: Identity-based encryption secure against selective opening attack. In: Ishai, Y. (ed.) TCC 2011. LNCS, vol. 6597, pp. 235–252. Springer, Heidelberg (2011). https://doi.org/10.1007/978-3-642-19571-6_15
Benhamouda, F., Herranz, J., Joye, M., Libert, B.: Efficient cryptosystems from \(2^k\)-th power residue symbols. J. Cryptol. 30(2), 519–549 (2017). https://doi.org/10.1007/s00145-016-9229-5
Böhl, F., Hofheinz, D., Kraschewski, D.: On definitions of selective opening security. In: Fischlin, M., Buchmann, J., Manulis, M. (eds.) PKC 2012. LNCS, vol. 7293, pp. 522–539. Springer, Heidelberg (2012). https://doi.org/10.1007/978-3-642-30057-8_31
Boldyreva, A., Fehr, S., O’Neill, A.: On notions of security for deterministic encryption, and efficient constructions without Random Oracles. In: Wagner, D. (ed.) CRYPTO 2008. LNCS, vol. 5157, pp. 335–359. Springer, Heidelberg (2008). https://doi.org/10.1007/978-3-540-85174-5_19
Boneh, D., Lewi, K., Montgomery, H., Raghunathan, A.: Key homomorphic PRFs and their applications. In: Canetti, R., Garay, J.A. (eds.) CRYPTO 2013, Part I. LNCS, vol. 8042, pp. 410–428. Springer, Heidelberg (2013). https://doi.org/10.1007/978-3-642-40041-4_23
Boyen, X., Li, Q.: All-but-many lossy trapdoor functions from lattices and applications. In: Katz, J., Shacham, H. (eds.) CRYPTO 2017, Part III. LNCS, vol. 10403, pp. 298–331. Springer, Cham (2017). https://doi.org/10.1007/978-3-319-63697-9_11
Brakerski, Z., Döttling, N., Garg, S., Malavolta, G.: Leveraging linear decryption: rate-1 fully-homomorphic encryption and time-lock puzzles. In: Hofheinz, D., Rosen, A. (eds.) TCC 2019, Part II. LNCS, vol. 11892, pp. 407–437. Springer, Cham (2019). https://doi.org/10.1007/978-3-030-36033-7_16
Brakerski, Z., Vaikuntanathan, V.: Lattice-based FHE as secure as PKE. In: Proceedings of the 5th Conference on Innovations in Theoretical Computer Science, ITCS 2014, pp. 1–12. ACM, New York (2014). https://doi.org/10.1145/2554797.2554799
Damgård, I., Nielsen, J.B.: Improved non-committing encryption schemes based on a general complexity assumption. In: Bellare, M. (ed.) CRYPTO 2000. LNCS, vol. 1880, pp. 432–450. Springer, Heidelberg (2000). https://doi.org/10.1007/3-540-44598-6_27
Damgård, I., Nielsen, J.B.: Perfect hiding and perfect binding universally composable commitment schemes with constant expansion factor. In: Yung, M. (ed.) CRYPTO 2002. LNCS, vol. 2442, pp. 581–596. Springer, Heidelberg (2002). https://doi.org/10.1007/3-540-45708-9_37
Dodis, Y., Reyzin, L., Smith, A.: Fuzzy extractors: how to generate strong keys from biometrics and other noisy data. In: Cachin, C., Camenisch, J.L. (eds.) EUROCRYPT 2004. LNCS, vol. 3027, pp. 523–540. Springer, Heidelberg (2004). https://doi.org/10.1007/978-3-540-24676-3_31
Döttling, N., Garg, S., Ishai, Y., Malavolta, G., Mour, T., Ostrovsky, R.: Trapdoor hash functions and their applications. In: Boldyreva, A., Micciancio, D. (eds.) CRYPTO 2019, Part III. LNCS, vol. 11694, pp. 3–32. Springer, Cham (2019). https://doi.org/10.1007/978-3-030-26954-8_1
Dwork, C., Naor, M., Reingold, O., Stockmeyer, L.J.: Magic functions. In: 40th FOCS, October 1999, pp. 523–534. IEEE Computer Society Press (1999). https://doi.org/10.1109/SFFCS.1999.814626
Fehr, S., Hofheinz, D., Kiltz, E., Wee, H.: Encryption schemes secure against chosen-ciphertext selective opening attacks. In: Gilbert, H. (ed.) EUROCRYPT 2010. LNCS, vol. 6110, pp. 381–402. Springer, Heidelberg (2010). https://doi.org/10.1007/978-3-642-13190-5_20
Freeman, D.M., Goldreich, O., Kiltz, E., Rosen, A., Segev, G.: More constructions of lossy and correlation-secure trapdoor functions. In: Nguyen, P.Q., Pointcheval, D. (eds.) PKC 2010. LNCS, vol. 6056, pp. 279–295. Springer, Heidelberg (2010). https://doi.org/10.1007/978-3-642-13013-7_17
Fujisaki, E.: All-but-many encryption. In: Sarkar, P., Iwata, T. (eds.) ASIACRYPT 2014. LNCS, vol. 8874, pp. 426–447. Springer, Heidelberg (2014). https://doi.org/10.1007/978-3-662-45608-8_23
Gentry, C., Halevi, S.: Compressible FHE with applications to PIR. In: Hofheinz, D., Rosen, A. (eds.) TCC 2019. LNCS, vol. 11892, pp. 438–464. Springer, Cham (2019). https://doi.org/10.1007/978-3-030-36033-7_17
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, Part I. LNCS, vol. 8042, pp. 75–92. Springer, Heidelberg (Aug 2013). https://doi.org/10.1007/978-3-642-40041-4_5
Goldwasser, S., Kalai, Y.T., Peikert, C., Vaikuntanathan, V.: Robustness of the learning with errors assumption. In: Yao, A.C.C. (ed.) ICS 2010, January 2010, pp. 230–240. Tsinghua University Press (2010)
Gustafsson, B.: Scientific Computing. TCSE, vol. 17. Springer, Cham (2018). https://doi.org/10.1007/978-3-319-69847-2
Hemenway, B., Libert, B., Ostrovsky, R., Vergnaud, D.: Lossy encryption: constructions from general assumptions and efficient selective opening chosen ciphertext security. In: Lee, D.H., Wang, X. (eds.) ASIACRYPT 2011. LNCS, vol. 7073, pp. 70–88. Springer, Heidelberg (2011). https://doi.org/10.1007/978-3-642-25385-0_4
Hemenway, B., Ostrovsky, R.: Extended-DDH and lossy trapdoor functions. In: Fischlin, M., Buchmann, J., Manulis, M. (eds.) PKC 2012. LNCS, vol. 7293, pp. 627–643. Springer, Heidelberg (May 2012). https://doi.org/10.1007/978-3-642-30057-8_37
Hemenway, B., Ostrovsky, R.: Building lossy trapdoor functions from lossy encryption. In: Sako, K., Sarkar, P. (eds.) ASIACRYPT 2013, Part II. LNCS, vol. 8270, pp. 241–260. Springer, Heidelberg (2013). https://doi.org/10.1007/978-3-642-42045-0_13
Heuer, F., Jager, T., Kiltz, E., Schäge, S.: On the selective opening security of practical public-key encryption schemes. In: Katz, J. (ed.) PKC 2015. LNCS, vol. 9020, pp. 27–51. Springer, Heidelberg (2015). https://doi.org/10.1007/978-3-662-46447-2_2
Heuer, F., Poettering, B.: Selective opening security from simulatable data encapsulation. In: Cheon, J.H., Takagi, T. (eds.) ASIACRYPT 2016, Part II. LNCS, vol. 10032, pp. 248–277. Springer, Heidelberg (2016). https://doi.org/10.1007/978-3-662-53890-6_9
Hofheinz, D.: All-but-many lossy trapdoor functions. In: Pointcheval, D., Johansson, T. (eds.) EUROCRYPT 2012. LNCS, vol. 7237, pp. 209–227. Springer, Heidelberg (2012). https://doi.org/10.1007/978-3-642-29011-4_14
Hofheinz, D., Jager, T., Rupp, A.: Public-key encryption with simulation-based selective-opening security and compact ciphertexts. In: Hirt, M., Smith, A. (eds.) TCC 2016, Part II. LNCS, vol. 9986, pp. 146–168. Springer, Heidelberg (2016). https://doi.org/10.1007/978-3-662-53644-5_6
Hofheinz, D., Rao, V., Wichs, D.: Standard security does not imply indistinguishability under selective opening. In: Hirt, M., Smith, A. (eds.) TCC 2016, Part II. LNCS, vol. 9986, pp. 121–145. Springer, Heidelberg (2016). https://doi.org/10.1007/978-3-662-53644-5_5
Hofheinz, D., Rupp, A.: Standard versus selective opening security: separation and equivalence results. In: Lindell, Y. (ed.) TCC 2014. LNCS, vol. 8349, pp. 591–615. Springer, Heidelberg (2014). https://doi.org/10.1007/978-3-642-54242-8_25
Huang, Z., Liu, S., Qin, B.: Sender-equivocable encryption schemes secure against chosen-ciphertext attacks revisited. In: Kurosawa, K., Hanaoka, G. (eds.) PKC 2013. LNCS, vol. 7778, pp. 369–385. Springer, Heidelberg (2013). https://doi.org/10.1007/978-3-642-36362-7_23
Kiltz, E., O’Neill, A., Smith, A.: Instantiability of RSA-OAEP under chosen-plaintext attack. In: Rabin, T. (ed.) CRYPTO 2010. LNCS, vol. 6223, pp. 295–313. Springer, Heidelberg (2010). https://doi.org/10.1007/978-3-642-14623-7_16
Libert, B., Sakzad, A., Stehlé, D., Steinfeld, R.: All-but-many lossy trapdoor functions and selective opening chosen-ciphertext security from LWE. In: Katz, J., Shacham, H. (eds.) CRYPTO 2017, Part III. LNCS, vol. 10403, pp. 332–364. Springer, Cham (2017). https://doi.org/10.1007/978-3-319-63697-9_12
Mahadev, U.: Classical homomorphic encryption for quantum circuits. In: Thorup, M. (ed.) 59th FOCS, October 2018, pp. 332–338. IEEE Computer Society Press (2018). https://doi.org/10.1109/FOCS.2018.00039
Micciancio, D., Peikert, C.: Trapdoors for lattices: simpler, tighter, faster, smaller. In: Pointcheval, D., Johansson, T. (eds.) EUROCRYPT 2012. LNCS, vol. 7237, pp. 700–718. Springer, Heidelberg (2012). https://doi.org/10.1007/978-3-642-29011-4_41
Mol, P., Yilek, S.: Chosen-ciphertext security from slightly lossy trapdoor functions. In: Nguyen, P.Q., Pointcheval, D. (eds.) PKC 2010. LNCS, vol. 6056, pp. 296–311. Springer, Heidelberg (2010). https://doi.org/10.1007/978-3-642-13013-7_18
Paillier, P.: Public-key cryptosystems based on composite degree residuosity classes. In: Stern, J. (ed.) EUROCRYPT 1999. LNCS, vol. 1592, pp. 223–238. Springer, Heidelberg (1999). https://doi.org/10.1007/3-540-48910-X_16
Pan, J., Zeng, R.: Compact and tightly selective-opening secure public-key encryption schemes. In: Agrawal, S., Lin, D. (eds.) Advances in Cryptology, ASIACRYPT 2022, vol. 13793, pp. 363–393. Springer Nature Switzerland, Cham (2022). https://doi.org/10.1007/978-3-031-22969-5_13
Peikert, C.: Public-key cryptosystems from the worst-case shortest vector problem: extended abstract. In: Mitzenmacher, M. (ed.) 41st ACM STOC, May/June 2009, pp. 333–342. ACM Press (2009). https://doi.org/10.1145/1536414.1536461
Peikert, C., Vaikuntanathan, V., Waters, B.: A framework for efficient and composable oblivious transfer. In: Wagner, D. (ed.) CRYPTO 2008. LNCS, vol. 5157, pp. 554–571. Springer, Heidelberg (2008). https://doi.org/10.1007/978-3-540-85174-5_31
Peikert, C., Waters, B.: Lossy trapdoor functions and their applications. In: Ladner, R.E., Dwork, C. (eds.) 40th ACM STOC, May 2008, pp. 187–196. ACM Press (2008). https://doi.org/10.1145/1374376.1374406
Pietrzak, K., Rosen, A., Segev, G.: Lossy functions do not amplify well. In: Cramer, R. (ed.) TCC 2012. LNCS, vol. 7194, pp. 458–475. Springer, Heidelberg (2012). https://doi.org/10.1007/978-3-642-28914-9_26
Regev, O.: On lattices, learning with errors, random linear codes, and cryptography. In: Gabow, H.N., Fagin, R. (eds.) 37th ACM STOC, May 2005, pp. 84–93. ACM Press (2005). https://doi.org/10.1145/1060590.1060603
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Hofheinz, D., Hostáková, K., Kastner, J., Klein, K., Ünal, A. (2024). Compact Selective Opening Security from LWE. In: Tang, Q., Teague, V. (eds) Public-Key Cryptography – PKC 2024. PKC 2024. Lecture Notes in Computer Science, vol 14604. Springer, Cham. https://doi.org/10.1007/978-3-031-57728-4_5
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