# CRYPTANALYSIS OF THE HFE PUBLIC KEY CRYPTOSYSTEM BY RELINEARIZATION PDF

Title, Cryptanalysis of the HFE Public Key Cryptosystem by Relinearization. Booktitle, Advances in Cryptology – CRYPTO ’99, 19th Annual International. Download Citation on ResearchGate | Cryptanalysis of the HFE Public Key Finally, we develop a new relinearization method for solving such systems for any. Finally, we develop a new relinearization method for solving such systems for any constant ffl? Cryptanalysis of the HFE Public Key Cryptosystem ().

Author: | Voran Zolojora |

Country: | Saint Kitts and Nevis |

Language: | English (Spanish) |

Genre: | Personal Growth |

Published (Last): | 9 December 2014 |

Pages: | 370 |

PDF File Size: | 15.94 Mb |

ePub File Size: | 3.71 Mb |

ISBN: | 910-9-21892-786-9 |

Downloads: | 90070 |

Price: | Free* [*Free Regsitration Required] |

Uploader: | Faeran |

So and satisfy the following equations derived from the bilinear equations, namely, where and all the coefficients in. So the adversary cannot derive from the publicly known map a low-rank matrix.

Patarin developed other schemes. However, some simple variants of HFE, such as the minus variant and the vinegar variant allow one to strengthen the basic HFE against all known attacks. Performance and Comparisons To make a comparison between the proposed HFE modification and the original HFE schemes in a uniform platform, we hfs the HFE scheme defined over and its extension field.

Then two invertible affine transformations are applied to hide the special structure of the central map [ 25 ]. The encryption scheme consists of three subalgorithms: Suggested Parameters Considering the aforementioned discussions, we suggest choosing and.

Notations Let be a -order finite field with being a prime power. It is based on a ground and cryptosysrem extension field.

It is shown that the proposed public key encryption scheme is secure against known attacks including the MinRank attack, the algebraic attacks, and the linearization equations attacks. This section does not cite any sources.

Retrieved from ” https: Thus we have some additional equations that associate with the plaintext ; namely, forwe have. However, the original Cryptozystem scheme was insecure, and the follow-up modifications were shown to be still vulnerable to attacks.

The HFE scheme firstly defines a univariate map over an extension field: We observe that the equation can be used to further destroy the special structure of the underlying central map of the HFE scheme. In the modified scheme, the public key isand hence we need not to store the coefficients of the square terms of the public key.

This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

To illustrate why the proposed modification of the Cryotanalysis scheme is secure against the MinRank attack [ 78 ], we just need to show that when lifted to the extension fieldthe quadratic part of the public key is not connected with a low-rank matrix.

## Security and Communication Networks

We represent the published system of multivariate polynomials by a single univariate polynomial of a special form over an extension field, and use it to reduce the cryptanalytic problem to a system of fflm 2 quadratic equations in m variables over the extension field.

Signatures are generated using the private key and are verified using the public key as follows. In this paper, we proposed a novel modified HFE encryption scheme. Given the ciphertextwe want to solve the plaintext from the quadratic equations: Conflicts of Interest The authors declare that they have no conflicts of interest.

El Din, and P. Without loss of generality, we assume that the two invertible affine transformations and are linear [ 21 ] and define the terms of in in 1. History of cryptography Cryptanalysis Outline of cryptography.

Description The encryption scheme consists of three subalgorithms: Security and Communication Networks. Loosely speaking, when we apply two linear transformations on the input and output of the mapthe rank of the corresponding matrix remains at most. Firstly, we define an HFE map in 1 and randomly choose two invertible affine transformations and.

As a new multivariate public key encryption, the security of the proposal needs to be furthered. In addition to HFE, J. In certain cases those polynomials could be defined over both a ground and an extension field. That is to say Or equivalently, The above equation says that we can lift the quadratic part of the public key to the extension field under some unknown linear transformations to derive and hence.

Symmetric-key algorithm Block cipher Stream cipher Public-key cryptography Cryptographic hash function Message authentication code Random numbers Steganography.

If we fail to derive a vector in form all the preimageswe output the symbol designating an invalid ciphertext. Thus by solving the MinRank problem we can determine the matrix and the coefficients of the linear transformation. For a plaintextwe just compute as the ciphertext.

### Multivariate cryptography – Wikipedia

These equations are called linearization equations and can be efficiently computed from the public polynomials. In the proposed modification HFE encryption scheme, we impose some restrictions on the plaintext space.

Views Read Edit View history. Then we merge the coefficients of the square and linear terms ofthat is, forand get the public key of the modified HFE scheme, namely, quadratic polynomialswhere, forThe secret key consists of, cryotanalysis. Abstract The RSA public key cryptosystem is based on a single modular equation in one variable. Advanced Search Include Citations. We analyze the security of the proposed HFE modified encryption scheme.

## J-GLOBAL – Japan Science and Technology Agency

In this paper we consider Patarin’s Hidden Field Equations HFE scheme, which is believed to be one of the strongest schemes of this type. The construction admits a standard isomorphism between the extension field and the vector space ; namely, for an elementwe have. The proposed method is a universal padding scheme and hence can be used to other multivariate cryptographic constructions. To make a comparison between the proposed HFE modification and the original HFE schemes in a uniform platform, we consider the HFE scheme defined over and relinearizztion extension field.

However, all known modification methods only can impose partial nonlinear transformation on the special structure of the HFE central map, and hence they are still vulnerable to some attacks [ 15 — 17 ]. So both cryptanalyss have the same secret key sizes and decryption costs. Solving cryptosysfem of multivariate polynomial equations is proven to be NP-hard or NP-complete.

Table of Contents Alerts.