scholarly journals The Oil and Vinegar Method

2020 ◽  
Author(s):  
William Buchanan
Keyword(s):  
Digital Signature ◽  
Public Key ◽  
Quantum Computers ◽  
Hard Problem ◽  
Public Key Encryption ◽  
Signature Schemes ◽  
Quadratic Equations ◽  
Private Key ◽  
Np Hard Problem ◽  
The Hard Problem

Public key encryption methods are often used to create a digital signature, and where Bob has a public key and a private key. In order to prove his identity, he will encrypt something related to the message with his private key, and which can then be checked with his public key. The main current methods of public-key encryption include RSA and ECC (Elliptic Curve Cryptography), and which involve computationally difficult operations. But these operations have not been proven to be hard in an era of quantum computers. One well-known hard problem is the solving of quadratic equations with $m$ equations with $n$ variables. This is a known NP-hard problem, even in a world of quantum computers. These can be used as post-quantum signature schemes and which involve multivariate equations. In order to understand these methods, this paper outlines a simple example of implementing the oil and vinegar method, and where we have a number of unknown oil variables and a number of known vinegar variables, and where the vinegar variables help convert the hard problem into an easy one.

Nonce-Based Key Agreement Protocol Against Bad Randomness

2019 ◽  
Vol 30 (04) ◽  
pp. 619-633
Author(s):  
Burong Kang ◽  
Xinyu Meng ◽  
Lei Zhang ◽  
Yinxia Sun
Keyword(s):  
Digital Signature ◽  
Key Agreement ◽  
Public Key ◽  
Security Model ◽  
Public Key Encryption ◽  
Signature Schemes ◽  
Key Agreement Protocol ◽  
Agreement Protocols

Most of the existing cryptographic schemes, e.g., key agreement protocol, call for good randomness. Otherwise, the security of these cryptographic schemes cannot be fully guaranteed. Nonce-based cryptosystem is recently introduced to improve the security of public key encryption and digital signature schemes by ensuring security when randomness fails. In this paper, we first investigate the security of key agreement protocols when randomness fails. Then we define the security model for nonce-based key agreement protocols and propose a nonce-based key agreement protocol that protects against bad randomness. The new protocol is proven to be secure in our proposed security model.

scholarly journals Efficient implementation of ideal lattice-based cryptography

2017 ◽  
Vol 59 (6) ◽  
Author(s):  
Thomas Pöppelmann
Keyword(s):  
Quantum Computer ◽  
Discrete Logarithm ◽  
Public Key ◽  
Quantum Computers ◽  
Ideal Lattice ◽  
Public Key Encryption ◽  
Signature Schemes ◽  
Good Balance ◽  
Almost All ◽  
Lattice Based Cryptography

AbstractAlmost all practically relevant asymmetric cryptosystems like RSA or ECC are either based on the hardness of factoring or on the hardness of the discrete logarithm problem. However, both problems could be solved efficiently on a large enough quantum computer. While quantum computers powerful enough to break currently used parameter sets are not available yet, they are heavily researched and expected to reach maturity in 15 to 20 years. As a consequence, research on alternative quantum-safe cryptosystems is required. One alternative is lattice-based cryptography which allows the construction of asymmetric public-key encryption and signature schemes that offer a good balance between security, performance, and key as well as ciphertext sizes.

Post-Quantum Blockchains

2020 ◽  
pp. 279-290
Author(s):  
Andreas Bolfing
Keyword(s):  
Digital Signature ◽  
Large Scale ◽  
Public Key ◽  
Quantum Computers ◽  
Cryptographic Primitives ◽  
Signature Schemes

Chapter 10 deals with the fact that quantum computers will break all current practical digital signature schemes once large-scale quantum computers become reality. The chapter starts with an outline of the major cryptographic primitives that are considered to be quantum-safe and compare their efficiency and usability for blockchain networks. For this, it compares the basic factors of the most popular classical public-key schemes and some chosen post-quantum approaches. This is followed by an introduction to hash-based cryptosystems. Based on Lamport-Diffie one-time signatures, it shows how hash-based signature schemes work and how they can be transformed to multi-signature schemes.

scholarly journals Secure Route Structures for Parallel Mobile Agents Based Systems Using Fast Binary Dispatch

2005 ◽  
Vol 1 (3) ◽  
pp. 185-205
Author(s):  
Yan Wang ◽  
Vijay Varadharajan
Keyword(s):  
Digital Signature ◽  
Mobile Agents ◽  
Large Scale ◽  
Public Key ◽  
Public Key Encryption ◽  
Distributed Environment ◽  
Signature Schemes ◽  
Route Information ◽  
Nested Structure ◽  
Mobile Agents Security

In a distributed environment, where a large number of computers are connected together to enable the large-scale sharing of data and computing resources, agents, especially mobile agents, are the tools for autonomously completing tasks on behalf of their owners. For applications of large-scale mobile agents, security and efficiency are of great concern. In this paper, we present a fast binary dispatch model and corresponding secure route structures for mobile agents dispatched in parallel to protect the dispatch routes of agents while ensuring the dispatch efficiency. The fast binary dispatch model is simple but efficient with a dispatch complexity of O(log2n. The secure route structures adopt the combination of public-key encryption and digital signature schemes and expose minimal route information to hosts. The nested structure can help detect attacks as early as possible. We evaluated the various models both analytically and empirically.

scholarly journals MISPLACED PRIORITIES: THE UTAH DIGITAL SIGNATURE ACT AND LIABILITY ALLOCATION IN A PUBLIC KEY INFRASTRUCTURE

2017 ◽  
Author(s):  
C. Bradford Biddle
Keyword(s):  
Digital Signature ◽  
Legal Status ◽  
Digital Signatures ◽  
Public Key Infrastructure ◽  
Public Key ◽  
Public Key Encryption ◽  
Electronic Documents ◽  
Online Databases ◽  
The Status ◽  
Computer Based

On March 9, 1995, the Utah Digital Signature Act (the “Utah Act”) was signed into law.1 Complex and ambitious, the Utah Act is intended to promote the use of digital signatures on computer-based documents and to facilitate electronic commerce.2 The Utah Act implements an infrastructure in which computer users utilize “certification authorities,” online databases called repositories, and public-key encryption technology in order to “sign” electronic documents in a legally binding fashion. In addition to setting out a regulatory scheme designed to implement this infrastructure, the Utah Act provides certain digital signatures with legal status as valid signatures and addresses a variety of issues relating to the status of digitally-signed electronic documents in contract and evidence law.

A Verifiable Ring Signature Scheme Based on Multivariate Public-Key Cryptosystem

2013 ◽  
Vol 380-384 ◽  
pp. 1899-1902
Author(s):  
Ling Ling Wang
Keyword(s):  
Public Key ◽  
Quantum Computers ◽  
Public Key Cryptosystem ◽  
Signature Scheme ◽  
Signature Schemes ◽  
Ring Signature ◽  
Multivariate Public Key

Most existing verifiable ring signature schemes are based on traditional PKCs, which cannot resist future attacks of quantum computers. Fortunately, the MQ-problem based Multivariate Public-Key Cryptosystem (MPKC) is an important alternative to traditional PKCs for its potential to resist future attacks of quantum computers. In this paper, we proposed a construction of verifiable ring signature based on MPKC, which has the properties of consistent, unforgery, signer-anonymity and verifiability.

A Blind Proxy Re-Signatures Scheme Based on Random Oracle

2011 ◽  
Vol 204-210 ◽  
pp. 1062-1065 ◽  
Author(s):  
Yu Qiao Deng
Keyword(s):  
Digital Signature ◽  
Digital Signatures ◽  
Random Oracle ◽  
Proxy Signature ◽  
Public Key ◽  
Signature Scheme ◽  
Signature Schemes

Digital signature schemes allow a signer to transform any message into a signed message, such that anyone can verify the validity of the signed message using the signer’s public key, but only the signer can generate signed messages. A proxy re-signature, which is a type of digital signatures, has significant applications in many areas. Proxy signature scheme was first introduced by Blaze, Bleumer, and Strauss, but that scheme is inefficient and with limited features. After that, some Proxy re-signature schemes were proposed by researchers. This paper constructs a blind proxy re-signatures scheme. Comparing to the previous proxy re-signature schemes, the scheme adds a message blinded feature, and then the security of the scheme is proven.

scholarly journals Analysis of the complexity of attacks on multivariate cryptographic transformations using algebraic field structure

Radiotekhnika ◽  
2021 ◽  
pp. 59-65
Author(s):  
S.O. Kandiy ◽  
G.A. Maleeva
Keyword(s):  
Comprehensive Analysis ◽  
Field Structure ◽  
Quantum Computers ◽  
Signature Scheme ◽  
Algebraic Field ◽  
Signature Schemes ◽  
Electronic Signature ◽  
World Community ◽  
Private Key ◽  
Standardization Process

In recent years, interest in cryptosystems based on multidimensional quadratic transformations (MQ transformations) has grown significantly. This is primarily due to the NIST PQC competition [1] and the need for practical electronic signature schemes that are resistant to attacks on quantum computers. Despite the fact that the world community has done a lot of work on cryptanalysis of the presented schemes, many issues need further clarification. NIST specialists are very cautious about the standardization process and urge cryptologists [4] in the next 3 years to conduct a comprehensive analysis of the finalists of the NIST PQC competition before their standardization. One of the finalists is the Rainbow electronic signature scheme [2]. It is a generalization of the UOV (Unbalanced Oil and Vinegar) scheme [3]. Recently, another generalization of this scheme – LUOV (Lifted UOV) [5] was found to attack [6], which in polynomial time is able to recover completely the private key. The peculiarity of this attack is the use of the algebraic structure of the field over which the MQ transformation is given. This line of attack has emerged recently and it is still unclear whether it is possible to use the field structure in the Rainbow scheme. The aim of this work is to systematize the techniques used in attacks using the algebraic field structure for UOV-based cryptosystems and to analyze the obstacles for their generalization to the Rainbow scheme.

scholarly journals Quantum Election Protocol Based on Quantum Public Key Cryptosystem

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Wenhua Gao ◽  
Li Yang
Keyword(s):  
Digital Signature ◽  
Large Scale ◽  
Third Party ◽  
Public Key ◽  
General Construction ◽  
Public Key Cryptosystem ◽  
Public Key Encryption ◽  
Quantum Digital Signature ◽  
Quantum Public Key ◽  
Quantum Public Key Cryptosystem

There is no quantum election protocol that can fulfil the eight requirements of an electronic election protocol, i.e., completeness, robustness, privacy, legality, unreusability, fairness, verifiability, and receipt-freeness. To address this issue, we employ the general construction of quantum digital signature and quantum public key encryption, in conjunction with classic public key encryption, to develop and instantiate a general construction of quantum election protocol. The proposed protocol exhibits the following advantages: (i) no pre-shared key between any two participants is required, and no trusted third party or anonymous channels are required. The protocol is suitable for large-scale elections with numerous candidates and voters and accommodates the situation in which multiple voters vote simultaneously. (ii) It is the first protocol that dismantles the contradiction between verifiability and receipt-freeness in a quantum election protocol. It satisfies all eight requirements stated earlier under the physical assumptions that there exists a one-way untappable channel from the administrator to the voter and that there is no collusion between any of the three parties in the protocol. Compared with current election protocols with verifiability and receipt-freeness, this protocol relies upon fewer physical assumptions. (iii) This construction is flexible and can be instantiated into an election scheme having post-quantum security by applying cryptographic algorithms conveying post-quantum security. Moreover, utilizing quantum digital signature and public key encryption yields a good result: the transmitted ballots are in quantum states, so owing to the no-cloning theorem, ballot privacy is less likely to be compromised, even if private keys of the signature and public key encryption are leaked after the election. However, in existing election protocols employing classic digital signatures and public key encryption, ballot privacy can be easily violated if attackers obtain private keys. Thus, our construction enhances privacy.

Certificates and Public Key Infrastructure

2008 ◽  
pp. 217-245
Author(s):  
Manuel Mogollon
Keyword(s):  
Access Control ◽  
Digital Signature ◽  
Public Key Infrastructure ◽  
Public Key ◽  
Comprehensive System ◽  
Public Key Encryption ◽  
Control Data ◽  
The Public ◽  
Digital Certificates ◽  
Public Keys

In public-key encryption, the secrecy of the public key is not required, but the authenticity of the public key is necessary to guarantee its integrity and to avoid spoofing and playback attacks. A user’s public key can be authenticated (signed) by a certificate authority that verifies that a public key belongs to a specific user. In this chapter, digital certificates, which are used to validate public keys, and certificate authorities are discussed. When public-key is used, it is necessary to have a comprehensive system that provides public key encryption and digital signature services to ensure confidentiality, access control, data integrity, authentication, and non-repudiation. That system, public-key infrastructure or PKI, is also discussed in this chapter.

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