Towards quantum-based privacy and voting

The privacy of communicating participants is often of paramount importance, but in some situations it is an essential condition. A typical example is a fair (secret) voting. We analyze in detail communication privacy based on quantum resources, and we propose new quantum protocols. Possible generalizations that would lead to voting schemes are discussed.Comment: 5 pages, improved description of the protoco

07421 Abstracts Collection -- Formal Protocol Verification Applied

From 14/10/2007 to 19/10/2007, the Dagstuhl Seminar 07421 ``Formal Protocol Verification Applied\u27\u27 was held in the International Conference and Research Center (IBFI), Schloss Dagstuhl. During the seminar, several participants presented their current research, and ongoing work and open problems were discussed. Abstracts of the presentations given during the seminar as well as abstracts of seminar results and ideas are put together in this paper. The first section describes the seminar topics and goals in general. Links to extended abstracts or full papers are provided, if available

Internet and the right of anonymity

This articles explores the ratio and characteristics of the right of anonymity on the Internet. A right of anonymity is considered as a shield against oppression, harassment, retaliation, censorship or discrimination and therefore it is considered as a vital component of freedom of speech or freedom of expression. Reference is made to several existing types of rights of anonymity in relation to freedom of expression, such as the right to protect (confidential) journalistic sources, free elections with secret ballot, the right of authors to create works under a pseudonym or anonymous, undercover or alias journalism... A right of anonymity however will inevitably have a relative character, due to society’s interest in determining one’s accountability, responsibility or liability in case of illegal or harmful content. In criminal law, for reasons of civil liability, for the protection of intellectual property law or in the area of commercial communications and advertising, the need for identification has reduced the scope of protection of one’s right to anonymity. It is explained how this approach is reflected in Principle 7 of the Declaration of the Council of Europe on Freedom of Communication on the Internet (28 May 2003). Striking a fair balance between the right of users of the Internet not to disclose their identity and tracing those responsible for criminal acts is the difficult but also inevitable challenge in this regard, a balance which cannot be found without respecting rigorously the human rights and fundamental freedoms of the involved persons. These rights and freedoms also need to be protected with extra procedural guarantees, e.g. regarding the disclosure of the identity by ISP’s or the detention of personal data by ISP’s and public authorities

A survey on group signature schemes

Group Signature, extension of digital signature, allows members of a group to sign messages on behalf of the group, such that the resulting signature does not reveal the identity of the signer. Any client can verify the authenticity of the document by using the public key parameters of the group. In case of dispute, only a designated group manager, because of his special property, is able to open signatures, and thus reveal the signer’s identity. Its applications are widespread, especially in e-commerce such as e-cash, e-voting and e-auction. This thesis incorporates the detailed study of various group signature schemes, their cryptographic concepts and the main contributions in this field. We implemented a popular group signature scheme based upon elliptic curve cryptosystems. Moreover, the group signature is dynamic i.e. remains valid, if some members leave the group or some new members join the group. Full traceability feature is also included in the implemented scheme. For enhanced security the the scheme implements distributed roles of the group manager. We also analysed various security features, formal models, challenges and cryptanalysis of some significant contributions in this area

Safeguarding the Unseen: a Study on Data Privacy in DeFi Protocols

The financial sector's adoption of technology-driven data analysis has enhanced operational efficiency and revenue generation by leveraging personal sensitive data. However, the inherent characteristics of blockchain hinder decentralized finance (DeFi) from accessing necessary sensitive user data. To address this challenge, we introduce a protocol that both safeguards user privacy and ensures data availability through the incorporation of homomorphic encryption and zero-knowledge-proof techniques in blockchain technology. This novel protocol helps mitigate privacy risks caused by sensitive data leaks while improving the capital efficiency of the DeFi market. Furthermore, we explore the applicability of these privacy-preserving methods in on-chain ecosystems and cross-border financial applications. Our solution contributes to secure, user-centric solutions for DeFi while upholding principles of decentralization and privacy protection