Privacy-Preserving Electronic Ticket Scheme with Attribute-based Credentials

Electronic tickets (e-tickets) are electronic versions of paper tickets, which enable users to access intended services and improve services' efficiency. However, privacy may be a concern of e-ticket users. In this paper, a privacy-preserving electronic ticket scheme with attribute-based credentials is proposed to protect users' privacy and facilitate ticketing based on a user's attributes. Our proposed scheme makes the following contributions: (1) users can buy different tickets from ticket sellers without releasing their exact attributes; (2) two tickets of the same user cannot be linked; (3) a ticket cannot be transferred to another user; (4) a ticket cannot be double spent; (5) the security of the proposed scheme is formally proven and reduced to well known (q-strong Diffie-Hellman) complexity assumption; (6) the scheme has been implemented and its performance empirically evaluated. To the best of our knowledge, our privacy-preserving attribute-based e-ticket scheme is the first one providing these five features. Application areas of our scheme include event or transport tickets where users must convince ticket sellers that their attributes (e.g. age, profession, location) satisfy the ticket price policies to buy discounted tickets. More generally, our scheme can be used in any system where access to services is only dependent on a user's attributes (or entitlements) but not their identities.Comment: 18pages, 6 figures, 2 table

A two authorities electronic vote scheme

[EN] In this paper we propose a new electronic multi-authority voting system based on blind signatures. We focus on the open problem of the efficiency of electronic voting systems. Most of the proposed systems rely on complex architectures or expensive proofs, in this work we aim to reduce the time-complexity of the voting process, both for the voter and the authorities involved. Our system is focused on simplicity and it is based on the assumption of two unrelated entities. This simplicity makes our approach scalable and flexible to multiple kinds of elections. We propose a method that limits the number of authorities to only 2 of them; we reduce the overall number of modular operations; and, propose a method which cut downs the interactions needed to cast a vote. The result is a voting protocol whose complexity scales linearly with the number of votes.Larriba-Flor, AM.; Sempere Luna, JM.; López Rodríguez, D. (2020). A two authorities electronic vote scheme. Computers & Security. 97:1-12. https://doi.org/10.1016/j.cose.2020.101940S11297Bloom, B. H. (1970). Space/time trade-offs in hash coding with allowable errors. Communications of the ACM, 13(7), 422-426. doi:10.1145/362686.362692Brams S., Fishburn P.C.. 2007. Approval voting Springer ScienceCarroll, T. E., & Grosu, D. (2009). A secure and anonymous voter-controlled election scheme. Journal of Network and Computer Applications, 32(3), 599-606. doi:10.1016/j.jnca.2008.07.010Chaum, D. L. (1981). Untraceable electronic mail, return addresses, and digital pseudonyms. Communications of the ACM, 24(2), 84-90. doi:10.1145/358549.358563Cramer, R., Gennaro, R., & Schoenmakers, B. (1997). A secure and optimally efficient multi-authority election scheme. European Transactions on Telecommunications, 8(5), 481-490. doi:10.1002/ett.4460080506Desmedt, Y. G. (2010). Threshold cryptography. European Transactions on Telecommunications, 5(4), 449-458. doi:10.1002/ett.4460050407Elgamal, T. (1985). A public key cryptosystem and a signature scheme based on discrete logarithms. IEEE Transactions on Information Theory, 31(4), 469-472. doi:10.1109/tit.1985.1057074Juang, W.-S. (2002). A Verifiable Multi-Authority Secret Election Allowing Abstention from Voting. The Computer Journal, 45(6), 672-682. doi:10.1093/comjnl/45.6.672Menezes A., van Oorschot P.C., Vanstone S.A.. 1996. Handbook of Applied Cryptography.Parhami, B. (1994). Voting algorithms. IEEE Transactions on Reliability, 43(4), 617-629. doi:10.1109/24.370218Rabin, M. O. (1980). Probabilistic Algorithms in Finite Fields. SIAM Journal on Computing, 9(2), 273-280. doi:10.1137/0209024Rabin, M. O. (1983). Transaction protection by beacons. Journal of Computer and System Sciences, 27(2), 256-267. doi:10.1016/0022-0000(83)90042-9Salazar, J. L., Piles, J. J., Ruiz-Mas, J., & Moreno-Jiménez, J. M. (2010). Security approaches in e-cognocracy. Computer Standards & Interfaces, 32(5-6), 256-265. doi:10.1016/j.csi.2010.01.004Nguyen, T. A. T., & Dang, T. K. (2013). Enhanced security in internet voting protocol using blind signature and dynamic ballots. Electronic Commerce Research, 13(3), 257-272. doi:10.1007/s10660-013-9120-5Wu, Z.-Y., Wu, J.-C., Lin, S.-C., & Wang, C. (2014). An electronic voting mechanism for fighting bribery and coercion. Journal of Network and Computer Applications, 40, 139-150. doi:10.1016/j.jnca.2013.09.011Yang, X., Yi, X., Nepal, S., Kelarev, A., & Han, F. (2018). A Secure Verifiable Ranked Choice Online Voting System Based on Homomorphic Encryption. IEEE Access, 6, 20506-20519. doi:10.1109/access.2018.2817518Yi, X., & Okamoto, E. (2013). Practical Internet voting system. Journal of Network and Computer Applications, 36(1), 378-387. doi:10.1016/j.jnca.2012.05.00

Applying Block Chain Technologies to Digital Voting Algorithms

Voting is a fundamental aspect to democracy. Many countries have advanced voting systems in place, but many of these systems have issues behind them such as not being anonymous or verifiable. Additionally, most voting systems currently have a central authority in charge of counting votes, which can be prone to corruption. We propose a voting system which mitigates many of these issues. Our voting system attempts to provide decentralization, pseudoanonymity, and verifiability. For our system, we have identified the requirements, implemented the backbone of the system, recognized some of its shortcomings, and proposed areas of future work on this voting system

New Blind Muti-signature Schemes based on ECDLP

In various types of electronic transactions, including election systems and digital cash schemes, user anonymity and authentication are always required. Blind signatures are considered the most important solutions to meeting these requirements. Many studies have focused on blind signature schemes; however, most of the studied schemes are single blind signature schemes. Although blind multi-signature schemes are available, few studies have focused on these schemes. In this article, blind multi-signature schemes are proposed based on the Elliptic Curve Discrete Logarithm Problem (ECDLP). The proposed schemes are based on the GOST R34.10-2012 digital signature standard and the EC-Schnorr digital signature scheme, and they satisfy blind multi-signature security requirements and have better computational performance than previously proposed schemes. The proposed schemes can be applied in election systems and digital cash schemes

A multi-candidate electronic voting scheme with unlimited participants

In this paper a new multi-candidate electronic voting scheme is constructed with unlimited participants. The main idea is to express a ballot to allow voting for up to k out of the m candidates and unlimited participants. The purpose of vote is to select more than one winner among $m$ candidates. Our result is complementary to the result by Sun peiyong$'$ s scheme, in the sense, their scheme is not amenable for large-scale electronic voting due to flaw of ballot structure. In our scheme the vote is split and hidden, and tallying is made for $G\ddot{o}del$ encoding in decimal base without any trusted third party, and the result does not rely on any traditional cryptography or computational intractable assumption. Thus the proposed scheme not only solves the problem of ballot structure, but also achieves the security including perfect ballot secrecy, receipt-free, robustness, fairness and dispute-freeness.Comment: 6 page

An Epistemic Approach to Coercion-Resistance for Electronic Voting Protocols

Coercion resistance is an important and one of the most intricate security requirements of electronic voting protocols. Several definitions of coercion resistance have been proposed in the literature, including definitions based on symbolic models. However, existing definitions in such models are rather restricted in their scope and quite complex. In this paper, we therefore propose a new definition of coercion resistance in a symbolic setting, based on an epistemic approach. Our definition is relatively simple and intuitive. It allows for a fine-grained formulation of coercion resistance and can be stated independently of a specific, symbolic protocol and adversary model. As a proof of concept, we apply our definition to three voting protocols. In particular, we carry out the first rigorous analysis of the recently proposed Civitas system. We precisely identify those conditions under which this system guarantees coercion resistance or fails to be coercion resistant. We also analyze protocols proposed by Lee et al. and Okamoto.Comment: An extended version of a paper from IEEE Symposium on Security and Privacy (S&P) 200

A novel e-voting system with diverse security features

Internet-based E-voting systems can offer great benefits over traditional voting machines in areas, such as protecting voter and candidate privacy, providing accurate vote counting, preventing voter fraud, and shortening the time of vote counting. This dissertation introduces, establishes and improves Internet-based E-voting systems on various aspects of the voting procedure. In addition, our designs also enable voters to track their votes which is a very important element in any elections. Our novel Internet-based E-voting system is based on the following realistic assumptions: (1) The election authorities are not 100% trustworthy; (2) The E-voting system itself is not 100% trustworthy; (3) Every voter is not 100% trustworthy. With these three basic assumptions, we can form mutual restrictions on each party, and secure measurements of the election will not be solely determined and influenced by any one of them. The proposed scheme, referred to as Time-lock algorithm based E-voting system with Ring signature and Multi-part form (TERM), is demonstrated to achieve the goal of keeping votes confidential and voters anonymous, as well as reducing the risk of leaking the voters’ identities during the election. In addition, TERM can prevent any possible clash attack, such as manipulating voting results or tampering voters’ original votes by malicious election authorities or hackers. The security performance analysis also shows that TERM provides outstanding measurements to secure the candidates’ manifest on each type of ballots during the whole election duration. TERM provides a roadmap for future fair elections via Internet