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 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.

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 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.

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 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 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.

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.

Cryptographic Primitives

2020 ◽  
pp. 57-134
Author(s):  
Andreas Bolfing
Keyword(s):  
Elliptic Curve ◽  
Elliptic Curves ◽  
Digital Signature ◽  
Discrete Logarithm ◽  
Public Key ◽  
Public Key Encryption ◽  
Cryptographic Primitives ◽  
Digital Signature Algorithm ◽  
Digital Signature Scheme ◽  
Current Standards

This chapter provides a very detailed introduction to cryptography. It first explains the cryptographic basics and introduces the concept of public-key encryption which is based on one-way and trapdoor functions, considering the three major public-key encryption families like integer factorization, discrete logarithm and elliptic curve schemes. This is followed by an introduction to hash functions which are applied to construct Merkle trees and digital signature schemes. As modern cryptoschemes are commonly based on elliptic curves, the chapter then introduces elliptic curve cryptography which is based on the Elliptic Curve Discrete Logarithm Problem (ECDLP). It considers the hardness of the ECDLP and the possible attacks against it, showing how to find suitable domain parameters to construct cryptographically strong elliptic curves. This is followed by the discussion of elliptic curve domain parameters which are recommended by current standards. Finally, it introduces the Elliptic Curve Digital Signature Algorithm (ECDSA), the elliptic curve digital signature scheme.

scholarly journals Delegating a Product of Group Exponentiations with Application to Signature Schemes (Submission to Special NutMiC 2019 Issue of JMC)

2020 ◽  
Vol 14 (1) ◽  
pp. 438-459
Author(s):  
Giovanni Di Crescenzo ◽  
Matluba Khodjaeva ◽  
Delaram Kahrobaei ◽  
Vladimir Shpilrain
Keyword(s):  
Elliptic Curves ◽  
Digital Signature ◽  
Cryptographic Protocols ◽  
Public Key ◽  
Small Probability ◽  
Signature Schemes ◽  
Cyclic Groups ◽  
Public Key Cryptosystems ◽  
Fixed Base

AbstractMany public-key cryptosystems and, more generally, cryptographic protocols, use group exponentiations as important primitive operations. To expand the applicability of these solutions to computationally weaker devices, it has been advocated that a computationally weaker client (i.e., capable of performing a relatively small number of modular multiplications) delegates such primitive operations to a computationally stronger server. Important requirements for such delegation protocols include privacy of the client’s input exponent and security of the client’s output, in the sense of detecting, except for very small probability, any malicious server’s attempt to convince the client of an incorrect exponentiation result. Only recently, efficient protocols for the delegation of a fixed-based exponentiation, over cyclic and RSA-type groups with certain properties, have been presented and proved to satisfy both requirements.In this paper we show that a product of many fixed-base exponentiations, over a cyclic groups with certain properties, can be privately and securely delegated by keeping the client’s online number of modular multiplications only slightly larger than in the delegation of a single exponentiation. We use this result to show the first delegations of entire cryptographic schemes: the well-known digital signature schemes by El-Gamal, Schnorr and Okamoto, over the q-order subgroup in ℤp, for p, q primes, as well as their variants based on elliptic curves. Previous efficient delegation results were limited to the delegation of single algorithms within cryptographic schemes.

Sign in / Sign up

Export Citation Format

Share Document