scholarly journals Committing to quantum resistance: a slow defence for Bitcoin against a fast quantum computing attack

2018 ◽  
Vol 5 (6) ◽  
pp. 180410 ◽  
Author(s):  
I. Stewart ◽  
D. Ilie ◽  
A. Zamyatin ◽  
S. Werner ◽  
M. F. Torshizi ◽  
...  

Quantum computers are expected to have a dramatic impact on numerous fields due to their anticipated ability to solve classes of mathematical problems much more efficiently than their classical counterparts. This particularly applies to domains involving integer factorization and discrete logarithms, such as public key cryptography. In this paper, we consider the threats a quantum-capable adversary could impose on Bitcoin, which currently uses the Elliptic Curve Digital Signature Algorithm (ECDSA) to sign transactions. We then propose a simple but slow commit–delay–reveal protocol, which allows users to securely move their funds from old (non-quantum-resistant) outputs to those adhering to a quantum-resistant digital signature scheme. The transition protocol functions even if ECDSA has already been compromised. While our scheme requires modifications to the Bitcoin protocol, these can be implemented as a soft fork.

Author(s):  
Keith M. Martin

In this chapter, we discuss digital signature schemes. We start by considering the general requirements of a digital signature scheme. We show first that a digital signature scheme could be established using symmetric techniques. We then consider the more conventional use of public-key cryptography to create digital signature schemes. We compare two different approaches to building a digital signature scheme and illustrate how to manifest these using RSA. We then discuss practical issues concerning digital signature schemes, including different aspects of their security. We close by providing a detailed comparison between digital signatures and handwritten signatures which serves to both illustrate the strengths and vulnerabilities of digital signature schemes.


Author(s):  
Quanxing Zhang ◽  
Chwan-Hwa Wu ◽  
J. David Irwin

A scheme is proposed in this chapter to apply a secure digital signature scheme in a mobile-IP environment and treats the three entities in a dynamic path as either foreign agents (FA), home agents (HA) or mobile agents (MA), such that a coalition is formed containing each of the individual agents. Each agent has a pair of keys: one private and one public. The private key is evolving with time, and the public key is signed by a certification authority (CA). All the private keys of the three agents in the coalition are needed to sign a signature. Furthermore, all the messages are signed and verified. The signature is verified against a public key, computed as the product of the public keys of all three agents, and readily generated when a new dynamic path is formed. In addition, the key-evolving scheme prevents an adversary from forging past signatures under any circumstances. As a result of the schemes’ proactive refresh capability, an adversary must simultaneously compromise each MA, FA and HA in order to forge future signatures. When a new dynamic path is formed or private keys evolve to new states, an interactive, proactive synchronization scheme is employed among the agents. Thus, the loss of a mobile device, or its information, will cause minimal information damage.


2014 ◽  
Vol 685 ◽  
pp. 579-582
Author(s):  
Shi Guo Jin ◽  
Guang Jiang Wang

Digital signature is electronically password technique for electronic document signature. Elliptic curve cryptography is a method of public key cryptography based on elliptic curve mathematical. Digital signature scheme consists of three processes: initialization process, the signature generation process and signature verification process system. This paper analyzes the elliptic curve cryptosystems mathematical principle and technical performance. The paper proposes design of digital signature scheme based on elliptic curve cryptosystem.


2011 ◽  
Vol 55-57 ◽  
pp. 1605-1608
Author(s):  
Fan Yu Kong ◽  
Jia Yu

At IWSEC 2008, F. Guo et al. proposed an efficient short signature scheme with batch verification based on C. Gentry’s scheme. In this paper, we firstly propose the key substitution attack on F. Guo et al.’s digital signature scheme and show that the malicious adversary can forge a valid signature, which can be verified with a substituted public key. Secondly, we prove that F. Guo et al.’s scheme is malleable and the attacker can produce a new valid signature on the message if he/she has known some valid signatures on the same message.


Sensors ◽  
2021 ◽  
Vol 21 (24) ◽  
pp. 8417
Author(s):  
P. Thanalakshmi ◽  
R. Anitha ◽  
N. Anbazhagan ◽  
Woong Cho ◽  
Gyanendra Prasad Joshi ◽  
...  

As a standard digital signature may be verified by anybody, it is unsuitable for personal or economically sensitive applications. The chameleon signature system was presented by Krawczyk and Rabin as a solution to this problem. It is based on a hash then sign model. The chameleon hash function enables the trapdoor information holder to compute a message digest collision. The holder of a chameleon signature is the recipient of a chameleon signature. He could compute collision on the hash value using the trapdoor information. This keeps the recipient from disclosing his conviction to a third party and ensures the privacy of the signature. The majority of the extant chameleon signature methods are built on the computationally infeasible number theory problems, like integer factorization and discrete log. Unfortunately, the construction of quantum computers would be rendered insecure to those schemes. This creates a solid requirement for construct chameleon signatures for the quantum world. Hence, this paper proposes a novel quantum secure chameleon signature scheme based on hash functions. As a hash-based cryptosystem is an essential candidate of a post-quantum cryptosystem, the proposed hash-based chameleon signature scheme would be a promising alternative to the number of theoretic-based methods. Furthermore, the proposed method is key exposure-free and satisfies the security requirements such as semantic security, non-transferability, and unforgeability.


Author(s):  
Andreas Bolfing

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.


2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Sergey E. Yunakovsky ◽  
Maxim Kot ◽  
Nikolay Pozhar ◽  
Denis Nabokov ◽  
Mikhail Kudinov ◽  
...  

AbstractQuantum computing technologies pose a significant threat to the currently employed public-key cryptography protocols. In this paper, we discuss the impact of the quantum threat on public key infrastructures (PKIs), which are used as a part of security systems for protecting production environments. We analyze security issues of existing models with a focus on requirements for a fast transition to post-quantum solutions. Although our primary focus is on the attacks with quantum computing, we also discuss some security issues that are not directly related to the used cryptographic algorithms but are essential for the overall security of the PKI. We attempt to provide a set of security recommendations regarding the PKI from the viewpoints of attacks with quantum computers.


Author(s):  
Léo Ducas ◽  
Eike Kiltz ◽  
Tancrède Lepoint ◽  
Vadim Lyubashevsky ◽  
Peter Schwabe ◽  
...  

In this paper, we present the lattice-based signature scheme Dilithium, which is a component of the CRYSTALS (Cryptographic Suite for Algebraic Lattices) suite that was submitted to NIST’s call for post-quantum cryptographic standards. The design of the scheme avoids all uses of discrete Gaussian sampling and is easily implementable in constant-time. For the same security levels, our scheme has a public key that is 2.5X smaller than the previously most efficient lattice-based schemes that did not use Gaussians, while having essentially the same signature size. In addition to the new design, we significantly improve the running time of the main component of many lattice-based constructions – the number theoretic transform. Our AVX2-based implementation results in a speed-up of roughly a factor of 2 over the previously best algorithms that appear in the literature. The techniques for obtaining this speed-up also have applications to other lattice-based schemes.


2014 ◽  
Vol 513-517 ◽  
pp. 4509-4512
Author(s):  
Xue Dong Dong ◽  
Xin Peng Jing

In this paper, the extended ElGamal public key cryptosystem and digital signature scheme with appendix are described in the setting of the group of units of the ring.Elements of the group of units with the larger order are used as the base elements in the proposed extension instead of primitive roots used in the original scheme. Proposed schemes make periodic change of the group and base elements to provide necessary security level.


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