scholarly journals A Multi-Party Contract Signing Solution Based on Blockchain

Electronics ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1457
Author(s):  
Josep-Lluis Ferrer-Gomila ◽  
M. Francisca Hinarejos
Keyword(s):  
Electronic Commerce ◽  
Digital Signature ◽  
Third Party ◽  
Trusted Third Party ◽  
Potential Intervention ◽  
Conflicting Evidence ◽  
Contract Signing ◽  
Minimize Costs

Fair digital signature of contracts and agreements is an essential process in any electronic commerce scenario, and therefore also in data marketplaces, where the relationships and agreements among the different parties (consumers and providers) are more dynamic. In multi-party contract signing, N parties wish to sign a contract in a such a way that either all signatories obtain evidence of the signing or none obtains conflicting evidence regarding the honest signatories; the exchange must be fair. In this paper, we propose a blockchain-based multi-party contract signing protocol. This solution does not require the existence or potential intervention of a trusted third party (TTP), thus avoiding the difficulty of N signatories agreeing upon a TTP. In addition, this proposal meets the necessary requirements: fairness, timeliness, non-repudiation of origin, and non-repudiation of receipt. Furthermore, confidentiality can be easily achieved. To minimize costs associated with the use of blockchain, it should be invoked in the case of exception (analogous to optimistic solutions with a TTP) and by only one of the N signatories. However, when the use of blockchain is required, we show that its cost is within perfectly manageable margins.

Verifiable Encryption of Digital Signatures Using Elliptic Curve Digital Signature Algorithm and its Implementation Issues

2007 ◽  
pp. 184-203
Author(s):  
R. Anitha ◽  
R. S. Sankarasubramanian
Keyword(s):  
Elliptic Curve ◽  
Digital Signature ◽  
Digital Signatures ◽  
Third Party ◽  
Simple Scheme ◽  
Trusted Third Party ◽  
Parallel Multiplier ◽  
Digital Signature Algorithm ◽  
Verifiable Encryption

This chapter presents a new simple scheme for verifiable encryption of elliptic curve digital signature algorithm (ECDSA). The protocol we present is an adjudicated protocol, that is, the trusted third party (TTP) takes part in the protocol only when there is a dispute. This scheme can be used to build efficient fair exchanges and certified email protocols. In this paper we also present the implementation issues. We present a new algorithm for multiplying two 2n bits palindromic polynomials modulo xp–1 for prime p = 2n + 1 for the concept defined in Blake, Roth, and Seroussi (1998), and it is compared with the Sunar-Koc parallel multiplier given in Sunar and Koc (2001).

Enhancing Privacy in PUF-Cash through Multiple Trusted Third Parties and Reinforcement Learning

2022 ◽  
Vol 18 (1) ◽  
pp. 1-26
Author(s):  
Georgios Fragkos ◽  
Cyrus Minwalla ◽  
Eirini Eleni Tsiropoulou ◽  
Jim Plusquellic
Keyword(s):  
User Anonymity ◽  
Third Party ◽  
Security And Privacy ◽  
Machine Learning Techniques ◽  
User Privacy ◽  
Trusted Third Party ◽  
Physical Unclonable Functions ◽  
Learning Techniques ◽  
Direct Contrast ◽  
Debit Cards

Electronic cash ( e-Cash ) is a digital alternative to physical currency such as coins and bank notes. Suitably constructed, e-Cash has the ability to offer an anonymous offline experience much akin to cash, and in direct contrast to traditional forms of payment such as credit and debit cards. Implementing security and privacy within e-Cash, i.e., preserving user anonymity while preventing counterfeiting, fraud, and double spending, is a non-trivial challenge. In this article, we propose major improvements to an e-Cash protocol, termed PUF-Cash, based on physical unclonable functions ( PUFs ). PUF-Cash was created as an offline-first, secure e-Cash scheme that preserved user anonymity in payments. In addition, PUF-Cash supports remote payments; an improvement over traditional currency. In this work, a novel multi-trusted-third-party exchange scheme is introduced, which is responsible for “blinding” Alice’s e-Cash tokens; a feature at the heart of preserving her anonymity. The exchange operations are governed by machine learning techniques which are uniquely applied to optimize user privacy, while remaining resistant to identity-revealing attacks by adversaries and trusted authorities. Federation of the single trusted third party into multiple entities distributes the workload, thereby improving performance and resiliency within the e-Cash system architecture. Experimental results indicate that improvements to PUF-Cash enhance user privacy and scalability.

scholarly journals Decentralized collaborative TTP free approach for privacy preservation in location based services

2019 ◽  
Vol 9 (6) ◽  
pp. 5376
Author(s):  
Ajaysinh Devendrasinh Rathod ◽  
Saurabh Shah ◽  
Vivaksha J. Jariwala
Keyword(s):  
Privacy Preservation ◽  
Location Privacy ◽  
Emergency Services ◽  
Personal Information ◽  
Personal Digital Assistant ◽  
Minimum Cost ◽  
Location Based Services ◽  
Third Party ◽  
Trusted Third Party ◽  
Recent Trends

In recent trends, growth of location based services have been increased due to the large usage of cell phones, personal digital assistant and other devices like location based navigation, emergency services, location based social networking, location based advertisement, etc. Users are provided with important information based on location to the service provider that results the compromise with their personal information like user’s identity, location privacy etc. To achieve location privacy of the user, cryptographic technique is one of the best technique which gives assurance. Location based services are classified as Trusted Third Party (TTP) & without Trusted Third Party that uses cryptographic approaches. TTP free is one of the prominent approach in which it uses peer-to-peer model. In this approach, important users mutually connect with each other to form a network to work without the use of any person/server. There are many existing approaches in literature for privacy preserving location based services, but their solutions are at high cost or not supporting scalability.  In this paper, our aim is to propose an approach along with algorithms that will help the location based services (LBS) users to provide location privacy with minimum cost and improve scalability.

scholarly journals A Quantum Dual-Signature Protocol Based on SNOP States without Trusted Participant

Entropy ◽  
2021 ◽  
Vol 23 (10) ◽  
pp. 1294
Author(s):  
Kejia Zhang ◽  
Xu Zhao ◽  
Long Zhang ◽  
Guojing Tian ◽  
Tingting Song
Keyword(s):  
Quantum Signature ◽  
Third Party ◽  
Trusted Third Party ◽  
Protocol Security ◽  
Verification Process ◽  
Orthogonal Product ◽  
First Time

Quantum dual-signature means that two signed quantum messages are combined and expected to be sent to two different recipients. A quantum signature requires the cooperation of two verifiers to complete the whole verification process. As an important quantum signature aspect, the trusted third party is introduced to the current protocols, which affects the practicability of the quantum signature protocols. In this paper, we propose a quantum dual-signature protocol without arbitrator and entanglement for the first time. In the proposed protocol, two independent verifiers are introduced, here they may be dishonest but not collaborate. Furthermore, strongly nonlocal orthogonal product states are used to preserve the protocol security, i.e., no one can deny or forge a valid signature, even though some of them conspired. Compared with existing quantum signature protocols, this protocol does not require a trusted third party and entanglement resources.

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