Abstract
An hard homogeneous space (HHS) is a finite group acting on a set with the group action being hard to invert and the set lacking any algebraic structure. As such HHS could potentially replace finite groups where the discrete logarithm is hard for building cryptographic primitives and protocols in a post-quantum world.
Threshold HHS-based primitives typically require parties to compute the group action of a secret-shared input on a public set element. On one hand this could be done through generic MPC techniques, although they incur in prohibitive costs due to the high complexity of circuits evaluating group actions known to date. On the other hand round-robin protocols only require black box usage of the HHS. However these are highly sequential procedures, taking as many rounds as parties involved. The high round complexity appears to be inherent due the lack of homomorphic properties in HHS, yet no lower bounds were known so far.
In this work we formally show that round-robin protocols are optimal. In other words, any at least passively secure distributed computation of a group action making black-box use of an HHS must take a number of rounds greater or equal to the threshold parameter. We furthermore study fair protocols in which all users receive the output in the same round (unlike plain round-robin), and prove communication and computation lower bounds of \(\varOmega (n \log _2 n)\) for n parties. Our results are proven in Shoup’s Generic Action Model (GAM), and hold regardless of the underlying computational assumptions.
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Notes
- 1.
Including one round to broadcast the result to other users.
- 2.
Or, in honest majority, to publicly reconstruct this user’s secret share.
- 3.
Due to our first result, this is also the best round complexity in this case.
- 4.
More precisely we later introduce a relation “\(\rightarrow \)” among query indices.
- 5.
Because it implies that computing \(a \mathop {\star }E_0\) can only be done through sequential applications of the group action starting from \(E_0\).
- 6.
Up to choosing paths satisfying a rather technical minimality condition.
- 7.
Even though broadcast could be achieved simply sending the same message to all parties, as we only focus on semi-honest adversaries.
- 8.
These can be defined for \(\mathbb {G}\) if \(\mathbb {Z}_N\) has an exceptional set of size at least n, with N being the order of \(\mathbb {G}\).
- 9.
Note |S| may be smaller than t if there are repetitions among \(i_1, \ldots , i_t\).
- 10.
r and \(r'\) are the first component of respectively the LHS and the RHS.
References
Atapoor, S., Baghery, K., Cozzo, D., Pedersen, R.: CSI-SharK: CSI-FiSh with sharing-friendly keys. In: Simpson, L., Rezazadeh Baee, M.A. (eds.) ACISP 2023. LNCS, vol. 13915, pp. 471–502. Springer, Cham (2023). https://doi.org/10.1007/978-3-031-35486-1_21
Atapoor, S., Baghery, K., Cozzo, D., Pedersen, R.: Practical robust DKG protocols for CSIDH. In: Tibouchi, M., Wang, X. (eds.) ACNS 2023. LNCS, pp. 219–247. Springer, Cham (2023). https://doi.org/10.1007/978-3-031-33491-7_9
Atapoor, S., Baghery, K., Cozzo, D., Pedersen, R.: VSS from distributed ZK proofs and applications. IACR Cryptology ePrint Archive, p. 992 (2023). https://eprint.iacr.org/2023/992
Baghery, K., Cozzo, D., Pedersen, R.: An isogeny-based ID protocol using structured public keys. In: Paterson, M.B. (ed.) IMACC 2021. LNCS, vol. 13129, pp. 179–197. Springer, Cham (2021). https://doi.org/10.1007/978-3-030-92641-0_9
Beullens, W., Disson, L., Pedersen, R., Vercauteren, F.: CSI-RAShi: distributed key generation for CSIDH. In: Cheon, J.H., Tillich, J.-P. (eds.) PQCrypto 2021 2021. LNCS, vol. 12841, pp. 257–276. Springer, Cham (2021). https://doi.org/10.1007/978-3-030-81293-5_14
Beullens, W., Dobson, S., Katsumata, S., Lai, Y.F., Pintore, F.: Group signatures and more from isogenies and lattices: generic, simple, and efficient. In: Dunkelman, O., Dziembowski, S. (eds.) EUROCRYPT 2022, Part II. LNCS, vol. 13276, pp. 95–126. Springer, Cham (2022). https://doi.org/10.1007/978-3-031-07085-3_4
Beullens, W., Katsumata, S., Pintore, F.: Calamari and Falafl: logarithmic (linkable) ring signatures from isogenies and lattices. In: Moriai, S., Wang, H. (eds.) ASIACRYPT 2020, Part II. LNCS, vol. 12492, pp. 464–492. Springer, Cham (2020). https://doi.org/10.1007/978-3-030-64834-3_16
Beullens, W., Kleinjung, T., Vercauteren, F.: CSI-FiSh: efficient isogeny based signatures through class group computations. In: Galbraith, S.D., Moriai, S. (eds.) ASIACRYPT 2019, Part I. LNCS, vol. 11921, pp. 227–247. Springer, Cham (2019). https://doi.org/10.1007/978-3-030-34578-5_9
Boneh, D., Guan, J., Zhandry, M.: A lower bound on the length of signatures based on group actions and generic isogenies. In: Hazay, C., Stam, M. (eds.) EUROCRYPT 2023, Part V. LNCS, vol. 14008, pp. 507–531. Springer, Cham (2023). https://doi.org/10.1007/978-3-031-30589-4_18
Campos, F., Muth, P.: On actively secure fine-grained access structures from isogeny assumptions. In: Cheon, J.H., Johansson, T. (eds.) PQCrypto 2022. LNCS, vol. 13512, pp. 375–398. Springer, Cham (2022). https://doi.org/10.1007/978-3-031-17234-2_18
Castryck, W., Decru, T.: An efficient key recovery attack on SIDH. In: Hazay, C., Stam, M. (eds.) EUROCRYPT 2023, Part V. LNCS, vol. 14008, pp. 423–447. Springer, Cham (2023). https://doi.org/10.1007/978-3-031-30589-4_15
Castryck, W., Lange, T., Martindale, C., Panny, L., Renes, J.: CSIDH: an efficient post-quantum commutative group action. In: Peyrin, T., Galbraith, S. (eds.) ASIACRYPT 2018, Part III. LNCS, vol. 11274, pp. 395–427. Springer, Cham (2018). https://doi.org/10.1007/978-3-030-03332-3_15
Catalano, D., Fiore, D., Gennaro, R., Giunta, E.: On the impossibility of algebraic vector commitments in pairing-free groups. In: Kiltz, E., Vaikuntanathan, V. (eds.) TCC 2022, Part II. LNCS, vol. 13748, pp. 274–299. Springer, Heidelberg (2022). https://doi.org/10.1007/978-3-031-22365-5_10
Cozzo, D., Smart, N.P.: Sashimi: cutting up CSI-FiSh secret keys to produce an actively secure distributed signing protocol. In: Ding, J., Tillich, J.-P. (eds.) PQCrypto 2020. LNCS, vol. 12100, pp. 169–186. Springer, Cham (2020). https://doi.org/10.1007/978-3-030-44223-1_10
De Feo, L., Galbraith, S.D.: SeaSign: compact isogeny signatures from class group actions. In: Ishai, Y., Rijmen, V. (eds.) EUROCRYPT 2019, Part III. LNCS, vol. 11478, pp. 759–789. Springer, Cham (2019). https://doi.org/10.1007/978-3-030-17659-4_26
De Feo, L., Meyer, M.: Threshold schemes from isogeny assumptions. In: Kiayias, A., Kohlweiss, M., Wallden, P., Zikas, V. (eds.) PKC 2020, Part II. LNCS, vol. 12111, pp. 187–212. Springer, Cham (2020). https://doi.org/10.1007/978-3-030-45388-6_7
Döttling, N., Hartmann, D., Hofheinz, D., Kiltz, E., Schäge, S., Ursu, B.: On the impossibility of purely algebraic signatures. In: Nissim, K., Waters, B. (eds.) TCC 2021, Part III. LNCS, vol. 13044, pp. 317–349. Springer, Cham (2021). https://doi.org/10.1007/978-3-030-90456-2_11
Duman, J., Hartmann, D., Kiltz, E., Kunzweiler, S., Lehmann, J., Riepel, D.: Generic models for group actions. In: Boldyreva, A., Kolesnikov, V. (eds.) PKC 2023, Part I. LNCS, vol. 13940, pp. 406–435. Springer, Heidelberg (2023). https://doi.org/10.1007/978-3-031-31368-4_15
El Kaafarani, A., Katsumata, S., Pintore, F.: Lossy CSI-FiSh: efficient signature scheme with tight reduction to decisional CSIDH-512. In: Kiayias, A., Kohlweiss, M., Wallden, P., Zikas, V. (eds.) PKC 2020, Part II. LNCS, vol. 12111, pp. 157–186. Springer, Cham (2020). https://doi.org/10.1007/978-3-030-45388-6_6
Fouotsa, T.B., Petit, C.: SHealS and HealS: isogeny-based PKEs from a key validation method for SIDH. In: Tibouchi, M., Wang, H. (eds.) ASIACRYPT 2021, Part IV. LNCS, vol. 13093, pp. 279–307. Springer, Cham (2021). https://doi.org/10.1007/978-3-030-92068-5_10
Giunta, E.: On the impossibility of algebraic NIZK in pairing-free groups. In: Handschuh, H., Lysyanskaya, A. (eds.) CRYPTO 2023. LNCS, vol. 14084, pp. 702–730. Springer, Cham (2023). https://doi.org/10.1007/978-3-031-38551-3_22
Lai, Y.-F., Galbraith, S.D., Delpech de Saint Guilhem, C.: Compact, efficient and UC-secure isogeny-based oblivious transfer. In: Canteaut, A., Standaert, F.-X. (eds.) EUROCRYPT 2021, Part I. LNCS, vol. 12696, pp. 213–241. Springer, Cham (2021). https://doi.org/10.1007/978-3-030-77870-5_8
Maino, L., Martindale, C., Panny, L., Pope, G., Wesolowski, B.: A direct key recovery attack on SIDH. In: Hazay, C., Stam, M. (eds.) EUROCRYPT 2023. LNCS, vol. 14008, pp. 448–471. Springer, Cham (2023). https://doi.org/10.1007/978-3-031-30589-4_16
Maurer, U.: Abstract models of computation in cryptography (invited paper). In: Smart, N.P. (ed.) Cryptography and Coding. LNCS, vol. 3796, pp. 1–12. Springer, Heidelberg (2005). https://doi.org/10.1007/11586821_1
Moriya, T., Onuki, H., Takagi, T.: SiGamal: a supersingular isogeny-based PKE and its application to a PRF. In: Moriai, S., Wang, H. (eds.) ASIACRYPT 2020, Part II. LNCS, vol. 12492, pp. 551–580. Springer, Cham (2020). https://doi.org/10.1007/978-3-030-64834-3_19
Papakonstantinou, P.A., Rackoff, C., Vahlis, Y.: How powerful are the DDH hard groups? Electron. Colloquium Comput. Complex. 167 (2012). https://eccc.weizmann.ac.il/report/2012/167
Robert, D.: Breaking SIDH in polynomial time. In: Hazay, C., Stam, M. (eds.) EUROCRYPT 2023, Part V. LNCS, vol. 14008, pp. 472–503. Springer, Cham (2023). https://doi.org/10.1007/978-3-031-30589-4_17
Rotem, L., Segev, G., Shahaf, I.: Generic-group delay functions require hidden-order groups. In: Canteaut, A., Ishai, Y. (eds.) EUROCRYPT 2020, Part III. LNCS, vol. 12107, pp. 155–180. Springer, Cham (2020). https://doi.org/10.1007/978-3-030-45727-3_6
Schul-Ganz, G., Segev, G.: Accumulators in (and beyond) generic groups: non-trivial batch verification requires interaction. In: Pass, R., Pietrzak, K. (eds.) TCC 2020, Part II. LNCS, vol. 12551, pp. 77–107. Springer, Cham (2020). https://doi.org/10.1007/978-3-030-64378-2_4
Shaw, S., Dutta, R.: Identification scheme and forward-secure signature in identity-based setting from isogenies. In: Huang, Q., Yu, Yu. (eds.) ProvSec 2021. LNCS, vol. 13059, pp. 309–326. Springer, Cham (2021). https://doi.org/10.1007/978-3-030-90402-9_17
Shor, P.W.: Algorithms for quantum computation: discrete logarithms and factoring. In: Proceedings of the 35th Annual Symposium on Foundations of Computer Science, pp. 124–134 (1994)
Shoup, V.: Lower bounds for discrete logarithms and related problems. In: Fumy, W. (ed.) EUROCRYPT 1997. LNCS, vol. 1233, pp. 256–266. Springer, Heidelberg (1997). https://doi.org/10.1007/3-540-69053-0_18
Stolbunov, A.: Cryptographic schemes based on isogenies (2012)
Tairi, E., Moreno-Sanchez, P., Maffei, M.: Post-quantum adaptor signature for privacy-preserving off-chain payments. In: Borisov, N., Diaz, C. (eds.) FC 2021, Part II. LNCS, vol. 12675, pp. 131–150. Springer, Heidelberg (2021). https://doi.org/10.1007/978-3-662-64331-0_7
Zhandry, M.: To label, or not to label (in generic groups). In: Dodis, Y., Shrimpton, T. (eds.) CRYPTO 2022, Part III. LNCS, vol. 13509, pp. 66–96. Springer, Cham (2022). https://doi.org/10.1007/978-3-031-15982-4_3
Acknowledgment
This work received funding from projects from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program under project PICOCRYPT (grant agreement No. 101001283), from SECURING Project (ref. PID2019-110873RJ-I00), from the Spanish Government under projects PRODIGY (TED2021-132464B-I00) and ESPADA (PID2022-142290OB-I00). The last two projects are co-funded by European Union EIE, and NextGenerationEU/PRTR fund.
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Cozzo, D., Giunta, E. (2023). Round-Robin is Optimal: Lower Bounds for Group Action Based Protocols. In: Rothblum, G., Wee, H. (eds) Theory of Cryptography. TCC 2023. Lecture Notes in Computer Science, vol 14372. Springer, Cham. https://doi.org/10.1007/978-3-031-48624-1_12
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