The PRIViLEDGE use cases have been carefully selected to demonstrate different aspects of privacy-enhancing cryptography applied to distributed ledgers.
The four use cases require the successful use of privacy-preserving techniques developed in PRIViLEDGE. Plus, the fourth use case addresses cryptographic protocols for software updates on distributed ledgers. These cryptographic guarantees enhance the standard assurance properties of the ledger in terms of availability, consistency, and immutability of the recorded data.
USE CASE 1: “E-voting” - Verifiable online voting with ledgers
Fair voting is one of the building blocks of modern democratic societies, and hence trustworthiness of a voting method is of crucial importance. Unfortunately, the requirements put to elections are partly contradictory. From the transparency point of view, we need universal verifiability, meaning that everyone should be able to check that all votes cast by eligible voters have been counted correctly. From the privacy point of view we must not disclose individual preferences of voters to anyone. In fact, it has been shown that the property of universal verifiability is not, under standard assumptions, achievable together with unconditional privacy, nor receipt-freeness.
- The prototype voting system implemented in PRIVILEDGE shows how DLT can be put to use for enabling verifiable online voting to achieve meaningful level of universal verifiability under the condition of voter privacy. Together with accompanying audit tools and procedural guidelines it shows how instead of trusting single service provider, it is possible to independently verify the correctness of the voting result in privacy preserving manner.
Read more about UC 1 HERE.
USE CASE 2: “Health insurance” - Distributed ledger for insurance
A health insurance system can be roughly modelled as interactions between three parties: patients, insurers, and care providers.
To motivate providers to focus on best results for patients while simultaneously keeping costs under control, insurers are increasingly interested to shift from the currently prevalent "fee for service" model—where the provider gets a pre-agreed fee for each treatment performed on an insured patient—to the "outcome- based contracting" (OBC) model—where the payments that providers receive depend on achieving specific measurable outcomes, like reducing the mean time off work for a certain diagnosis or lowering the number of patients with blood pressure exceeding a threshold.
To be able to affect such broad outcomes, care providers with different specializations typically join into an "accountable care organization" (ACO) to share the responsibilities as well as the financial rewards and risks. In practice, the ACO contracts are not pure outcome-based, but combine different payment models in various proportions.
- PRIViLEDGE provides a prototype health insurance system that combines secure multi-party computation among the ACO members with zero-knowledge proofs that enable the insurers to verify the correctness of the reports without leaking the details of individual patients. Showing the possibility of such privacy-preserving reporting will encourage wider deployment of the OBC model and thus advance the efficiency of the medical insurance in particular and the healthcare sector in general.
Read more about UC 2 HERE.
USE CASE 3: “eDiploma” - University diploma record ledger
The printed-paper certificate system has repeatedly been a cause of concern for security and reliability, because it allows fraudsters to forge certificates. Also, there is no definite mechanism to easily verify and check the authenticity of a certificate.
Current approaches designed to overcome the disadvantages of paper-based academic certificates has not addressed issues like the validation of claimed certificates yet. In addition, it is based on centralised solutions that can be targeted by malicious users.
- PRIViLEDGE will create a distributed, secure ledger of higher education degrees in Greece. The ledger will contain transactions certifying that a student has obtained a degree from a given institution. Each institution will run a node of the distributed ledger, so that false records will not be inserted unless 50%+1 of the participating institutions are compromised. The risks from losing original data will be minimised, as all institutions will contain copies of all degrees.
Read more about UC 3 HERE.
USE CASE 4: Update mechanism for Cardano stake-based ledgers
No matter how carefully any complex software system will be designed and implemented, there will always be a need for future updates and improvements when new requirements arise, bugs are discovered, standards or protocols change, or new technologies become relevant.
Traditionally, such software updates have been handled in an ad-hoc, centralised manner. Meaning that somebody, often a trusted authority, or the original author of the software, provides a new version of the software, and users download and install it from that authority’s website (or they don’t).
Public ledger systems, although decentralized by nature, very often follow a centralized approach for software updates. So, there is a lot of room for improvement, especially in the decentralization aspect of the update systems used today.
The traditional way of handling software updates is neither decentralised nor secure, nor does it apply the decentralisation and security achieved by modern blockchain technology to the handling of updates for the systems themselves.
- PRIViLEDGE defines a novel decentralized software updates framework for stake-based ledger systems. This framework follows a holistic approach and examines a software update throughout its whole lifecycle. All the phases in the lifecycle of a software update in the centralized setting have been studied and ''decentralized alternatives'' for all of them have been proposed by the Priviledge team.
Read more about UC 4 HERE.