Please describe your proposed solution

While searching the blockchain using a third party tool like an explorer on the Internet a user has to reveal the search term like address or staking address to receive matching results. Such information is sensitive and ideally kept private.

I am researching and developing a new type of blockchain information search that maintains a good level of privacy and provably returns correct results. This is achieved on the user's end with encoding the query in a filter using hashing the search terms. The filter is then handed over to a third party service which applies it to a blockchain search and returns the matching results to the client. In a final step this result set is further trimmed on the user's end to extract the true results.

The query is not revealed to the service in plaintext. It only learns about the query's results, which contain the true results but also many false positives.

There is some overhead involved in this type of search which is inevitable. In the research paper I am quantifying the overhead and discuss strategies to optimise the search. Also shown is an evaluation of the new method, which is benchmarked against a search without privacy preservation.

Please define the positive impact your project will have on the wider Cardano community

Improved privacy in searching the Cardano blockchain.

I imagine that there will be paid services to run safer blockchain queries, or that current explorer implementations will adopt the new type of search.

Marketing USP: this is an innovative and novel implementation of blockchain search preserving users' privacy that to my knowledge does not yet exist in other blockchain projects.

What is your capability to deliver your project with high levels of trust and accountability? How do you intend to validate if your approach is feasible?

I have working experience with Cardano since its mainnet launch in 2017. I have been working with IOHK (later IOG) from 2018 until 2023 on the node and on commercial blockchain solutions.

I team up with Blockchain Data Analytics who has delivered a number of solutions to the Cardano community.

The feasibility is covered from a theoretical point of view: the underlying theory of Bloom's filters is well established and understood. It has been shown that searching with a Bloom's filter outputs a result set that provably contains the true positives. I will concentrate on the evaluation of the performance overhead that this type of search has and the implementation and completion of the service as an MVP.

What are the key milestones you need to achieve in order to complete your project successfully?

Milestone 1: M1: research paper

duration: 2 months

goal: investigation and research into privacy preserving blockchain search using statistical filters

output: sketch of the paper, a number of tests of the new search, specification for the implementation in milestone M2.

acceptance criteria:

• sketch of the paper with research into statistical filters and its application to blockchain search
• tests of the new search
• specification for the implementation

The research paper establishes the foundation of this project by applying statistical filters to blockchain search. It outlines the improvement of users' privacy when using such a service. It will also estimate the increased complexity and computational overhead in comparison with a direct search and shall discuss potential optimisations. These results will guide then the implementation of the MVP in the later milestones.

Milestone 2: M2: implementation of PoC

duration: 1 month

goal: implementation of backend search functionality, and webapp frontend with encoding and post-filtering

output: code published in the Github repository, tests, working backend and web application

acceptance criteria:

• Github repository contains code and tests
• There is a working backend and web application PoC

Implementation of Bloom's filter in C for the database search. Encoding of the search query using hashing on the client in the frontend. The returned result sets are filtered for the true positives.

Milestone 3: M3: data gathering and analysis

duration: 1 month

goal: evaluation of runtime behaviour and optimisation strategies

output: code and data published in the Github repository, data analyses, tables and graphs added to the paper

acceptance criteria:

• Github repository contains code and data
• Data analysed, and tables and graphs added to the paper

Final Milestone: M4: finalisation and submission of the research paper

duration: 1 month

goal: write up and submission of the paper as Open Access

output: documentation published in the Github repository, preprint version of the paper online available

acceptance criteria:

• Github repository contains code and data
• Data analysed, and tables and graphs added to the paper

Who is in the project team and what are their roles?

Alexander Diemand, https://www.linkedin.com/in/axeld/

role: initiating the project, research and design & architecture responsibility, and leading the development to ensure delivery on every milestone.

Please provide a cost breakdown of the proposed work and resources

M1: 2 x $8000 = $16000

M2: $8000

M3: $8000

M4: $8000 + $2500 (publication fee) = $10500

cloud infrastructure costs: $1000 (5 months at $200 per month)

sum: $43500 eq ADA 108000

(1 ADA eq $0.4)

No dependencies.

How does the cost of the project represent value for money for the Cardano ecosystem?

Marketing: this represents a true USP that distinguishes the Cardano blockchain from other projects in the domain.

Volume: the Cardano blockchain is renowned for stability, and improved user privacy means it might attract more investors/HODLers.

Most of the granted value will be spent on labour.

The project results in various artefacts that will influence the Cardano community:

• The research paper will communicate the idea and show the feasibility of the approach.
• The implemented service will allow users to search the blockchain with improved privacy.
• The Open Source code will allow everyone to reimplement this in their own projects.