Abstract
In 2016, Yasuda et al. presented a new multivariate encryption technique based on the Square and Rainbow primitives and utilizing the plus modifier that they called SRP. The scheme achieved a smaller blow-up factor between the plaintext space and ciphertext space than most recent multivariate encryption proposals, but proved to be too aggressive and was completely broken by Perlner et al. in 2017. The scheme suffered from the same MinRank weakness that has allowed effective attacks on several notable big field multivariate schemes: HFE, multi-HFE, HFE-, for example.
We propose a related new encryption scheme retaining the desirable traits of SRP and patching its weaknesses. We call the scheme HFERP because it utilizes a similar construction as SRP with an HFE primitive replacing the Square polynomial. The effect of this substitution is to increase the Q-rank of the pubic key to such a degree that the MinRank attack is impossible. HFERP still retains the relatively small blow-up factor between the plaintext space and ciphertext space, and is thus a candidate for secure multivariate encryption without an essential doubling in size between plaintext and ciphertext.
The rights of this work are transferred to the extent transferable according to title 17 \(\S \) 105 U.S.C.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Similar content being viewed by others
Notes
- 1.
Certain commercial equipment, instruments, or materials are identified in this paper in order to specify the experimental procedure adequately. Such identification is not intended to imply recommendation or endorsement by the National Institute of Standards and Technology, nor is it intended to imply that the materials or equipment identified are necessarily the best available for the purpose.
References
Shor, P.W.: Polynomial-time algorithms for prime factorization and discrete logarithms on a quantum computer. SIAM J. Sci. Stat. Comput. 26, 1484 (1997)
Mosca, M.: Cybersecurity in a quantum world: will we be ready? In: Workshop on Cybersecurity in a Post-Quantum World, Invited Presentation (2015). https://csrc.nist.gov/csrc/media/events/workshop-on-cybersecurity-in-a-post-quantum-world/documents/presentations/session8-mosca-michele.pdf
Yasuda, T., Sakurai, K.: A multivariate encryption scheme with rainbow. In: Qing, S., Okamoto, E., Kim, K., Liu, D. (eds.) ICICS 2015. LNCS, vol. 9543, pp. 236–251. Springer, Cham (2016). https://doi.org/10.1007/978-3-319-29814-6_19
Kipnis, A., Patarin, J., Goubin, L.: Unbalanced oil and vinegar signature schemes. In: Stern, J. (ed.) EUROCRYPT 1999. LNCS, vol. 1592, pp. 206–222. Springer, Heidelberg (1999). https://doi.org/10.1007/3-540-48910-X_15
Ding, J., Schmidt, D.: Rainbow, a new multivariable polynomial signature scheme. In: Ioannidis, J., Keromytis, A., Yung, M. (eds.) ACNS 2005. LNCS, vol. 3531, pp. 164–175. Springer, Heidelberg (2005). https://doi.org/10.1007/11496137_12
Petzoldt, A., Chen, M.-S., Yang, B.-Y., Tao, C., Ding, J.: Design principles for HFEv- based multivariate signature schemes. In: Iwata, T., Cheon, J.H. (eds.) ASIACRYPT 2015. LNCS, vol. 9452, pp. 311–334. Springer, Heidelberg (2015). https://doi.org/10.1007/978-3-662-48797-6_14
Patarin, J.: Hidden fields equations (HFE) and isomorphisms of polynomials (IP): two new families of asymmetric algorithms. In: Maurer, U. (ed.) EUROCRYPT 1996. LNCS, vol. 1070, pp. 33–48. Springer, Heidelberg (1996). https://doi.org/10.1007/3-540-68339-9_4
Tao, C., Diene, A., Tang, S., Ding, J.: Simple matrix scheme for encryption. In: Gaborit, P. (ed.) PQCrypto 2013. LNCS, vol. 7932, pp. 231–242. Springer, Heidelberg (2013). https://doi.org/10.1007/978-3-642-38616-9_16
Ding, J., Petzoldt, A., Wang, L.: The cubic simple matrix encryption scheme. [32], pp. 76–87 (2014)
Porras, J., Baena, J., Ding, J.: ZHFE, A new multivariate public key encryption scheme. [32], pp. 229–245 (2014)
Moody, D., Perlner, R.A., Smith-Tone, D.: An asymptotically optimal structural attack on the ABC multivariate encryption scheme. [32], pp. 180–196 (2014)
Moody, D., Perlner, R., Smith-Tone, D.: Key recovery attack on the cubic ABC simple matrix multivariate encryption scheme. In: Avanzi, R., Heys, H. (eds.) SAC 2016. LNCS, vol. 10532, pp. 543–558. Springer, Cham (2017). https://doi.org/10.1007/978-3-319-69453-5_29
Moody, D., Perlner, R.A., Smith-Tone, D.: Improved attacks for characteristic-2 parameters of the cubic ABC simple matrix encryption scheme. [31], pp. 255–271 (2017)
Cabarcas, D., Smith-Tone, D., Verbel, J.A.: Key recovery attack for ZHFE. [31], pp. 289–308 (2017)
Vates, J., Smith-Tone, D.: Key recovery attack for all parameters of HFE-. [31], pp. 272–288 (2017)
Perlner, R., Petzoldt, A., Smith-Tone, D.: Total break of the SRP encryption scheme. In: Adams, C., Camenisch, J. (eds.) SAC 2017. LNCS, vol. 10719, pp. 355–373. Springer, Cham (2018). https://doi.org/10.1007/978-3-319-72565-9_18
Matsumoto, T., Imai, H.: Public quadratic polynomial-tuples for efficient signature-verification and message-encryption. In: Barstow, D., Brauer, W., Brinch Hansen, P., Gries, D., Luckham, D., Moler, C., Pnueli, A., Seegmüller, G., Stoer, J., Wirth, N., Günther, C.G. (eds.) EUROCRYPT 1988. LNCS, vol. 330, pp. 419–453. Springer, Heidelberg (1988). https://doi.org/10.1007/3-540-45961-8_39
Berlekamp, E.R.: Factoring polynomials over large finite fields. Math. Comput. 24, 713–735 (1970)
Clough, C., Baena, J., Ding, J., Yang, B.-Y., Chen, M.: Square, a new multivariate encryption scheme. In: Fischlin, M. (ed.) CT-RSA 2009. LNCS, vol. 5473, pp. 252–264. Springer, Heidelberg (2009). https://doi.org/10.1007/978-3-642-00862-7_17
Patarin, J.: The oil and vinegar algorithm for signatures. Presented at the Dagsthul Workshop on Cryptography (1997)
Patarin, J., Goubin, L., Courtois, N.: \(C_{-+}^{*}\), and HM: variations around two schemes of T. Matsumoto and H. Imai. In: Ohta, K., Pei, D. (eds.) ASIACRYPT 1998. LNCS, vol. 1514, pp. 35–50. Springer, Heidelberg (1998). https://doi.org/10.1007/3-540-49649-1_4
Kipnis, A., Shamir, A.: Cryptanalysis of the oil and vinegar signature scheme. In: Krawczyk, H. (ed.) CRYPTO 1998. LNCS, vol. 1462, pp. 257–266. Springer, Heidelberg (1998). https://doi.org/10.1007/978-3-319-72565-9_18
Kipnis, A., Shamir, A.: Cryptanalysis of the HFE public key cryptosystem by relinearization. In: Wiener, M. (ed.) CRYPTO 1999. LNCS, vol. 1666, pp. 19–30. Springer, Heidelberg (1999). https://doi.org/10.1007/3-540-48405-1_2
Faugère, J., Din, M.S.E., Spaenlehauer, P.: Computing loci of rank defects of linear matrices using Gröbner bases and applications to cryptology. In: Koepf, W. (ed.) Proceedings of International Symposium on Symbolic and Algebraic Computation, ISSAC 2010, Munich, Germany, 25–28 July 2010, pp. 257–264. ACM (2010)
Bettale, L., Faugère, J., Perret, L.: Cryptanalysis of HFE, multi-HFE and variants for odd and even characteristic. Des. Codes Cryptogr. 69, 1–52 (2013)
Ding, J., Hodges, T.J.: Inverting HFE systems is quasi-polynomial for all fields. In: Rogaway, P. (ed.) CRYPTO 2011. LNCS, vol. 6841, pp. 724–742. Springer, Heidelberg (2011). https://doi.org/10.1007/978-3-642-22792-9_41
Goubin, L., Courtois, N.T.: Cryptanalysis of the TTM cryptosystem. In: Okamoto, T. (ed.) ASIACRYPT 2000. LNCS, vol. 1976, pp. 44–57. Springer, Heidelberg (2000). https://doi.org/10.1007/3-540-44448-3_4
Bosma, W., Cannon, J., Playoust, C.: The Magma algebra system. I: the user language. J. Symb. Comput. 24, 235–265 (1997). Computational algebra and number theory (London, 1993)
Yang, B.-Y., Chen, J.-M.: Theoretical analysis of XL over small fields. In: Wang, H., Pieprzyk, J., Varadharajan, V. (eds.) ACISP 2004. LNCS, vol. 3108, pp. 277–288. Springer, Heidelberg (2004). https://doi.org/10.1007/978-3-540-27800-9_24
Bardet, M., Faugre, J., Salvy, B., Yang, B.: Asymptotic behaviour of the degree of regularity of semi-regular polynomial systems. In: MEGA 2005 Eighth International Symposium On Effective Methods in Algebraic Geometry (2005)
Lange, T., Takagi, T. (eds.): PQCrypto 2017. LNCS, vol. 10346. Springer, Cham (2017). https://doi.org/10.1007/978-3-319-59879-6
Mosca, M. (ed.): PQCrypto 2014. LNCS, vol. 8772. Springer, Cham (2014). https://doi.org/10.1007/978-3-319-11659-4
Acknowledgments
The first and fourth authors were supported by JST CREST (Grant Number JPMJCR14D6).
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
A Toy Example
A Toy Example
The purpose of the following toy example is to help the reader understand the process of generating a public key for an instance of HFERP as well as an example of encryption and decryption. The parameters used are by no means secure and are soley for instructional purposes.
Parameters of this toy example are as follows: \(q=7,~d=o=r=2,~s=1, \text {and}~ l=0\). Then, construct \(\mathbb {E}\) a degree 2 extension field over \(\mathbb {F}_7\). The chosen HFE core map is \(f=\xi ^{12}X^{14}+\xi ^{6}X^8+\xi ^{29}X^2\) where \(\xi \in \mathbb {E}\). Let \(\mathcal {T}\) and \(\mathcal {U}\) be the following affine maps:
With the parameters described above, \(\mathcal {F}\) can be represented as the following matrices over \(\mathbb {F}_7\)
\(P_1\) and \(P_2\) represent the HFE component, \(P_3 \rightarrow P_6\) represent the rainbow component, and \(P_7\) represents the plus component. With the public key generated by \(\mathcal {P}=\mathcal {T}\circ \mathcal {F}\circ \mathcal {U}\), its matrix form over \(\mathbb {F}_7\) is:
Given the following plaintext, (2, 6, 1, 5), the resulting ciphertext is (0, 0, 1, 3, 0, 4, 0).
Decryption: Given a ciphertext (0, 0, 1, 3, 0, 4, 0), the following process is how you would obtain its corresponding plaintext.
Part of the secret key:
Feed the ciphertext through \(\mathcal {T}^{-1}\) to get
The first \(d=2\) elements are the corresponding HFE outputs. Take these elements and adjust the HFE core map as follows:
Perform the Berlekamp algorithm to find the preimage of f. In doing so in this toy example, you get (0, 6). Next, construct the vector:
Construct equations of the form \(\overline{u}F_1\overline{u}^\top = x_i\) where \(x_i\) refers to the \(i^{th}\) element of (7), for \(i \in \{3,4,5,6\}\). This will result with the following equations:
Solving this system of equations gives us \(u_1=6\) and \(u_2=6\). Thus,
Finally, feed this through \(\mathcal {U}^{-1}\) to get the plaintext, \(\left[ 2,6,1,5 \right] \).
Rights and permissions
Copyright information
© 2018 Springer International Publishing AG, part of Springer Nature (outside the US)
About this paper
Cite this paper
Ikematsu, Y., Perlner, R., Smith-Tone, D., Takagi, T., Vates, J. (2018). HFERP - A New Multivariate Encryption Scheme. In: Lange, T., Steinwandt, R. (eds) Post-Quantum Cryptography. PQCrypto 2018. Lecture Notes in Computer Science(), vol 10786. Springer, Cham. https://doi.org/10.1007/978-3-319-79063-3_19
Download citation
DOI: https://doi.org/10.1007/978-3-319-79063-3_19
Published:
Publisher Name: Springer, Cham
Print ISBN: 978-3-319-79062-6
Online ISBN: 978-3-319-79063-3
eBook Packages: Computer ScienceComputer Science (R0)