Shutter API: Encryption-as-a-Service (Dev tooling + dApp)

[Proposal setup] Proposal title

Please provide your proposal title

Shutter API: Encryption-as-a-Service (Dev tooling + dApp)

[Proposal Summary] Budget Information

Enter the amount of funding you are requesting in ADA

200000

[Proposal Summary] Time

Please specify how many months you expect your project to last

9

[Proposal Summary] Translation Information

Please indicate if your proposal has been auto-translated

No

Original Language

en

[Proposal Summary] Problem Statement

What is the problem you want to solve?

Cardano lacks dev tooling for private, trust-minimized apps that ensure fairness, prevent front-running and information asymmetry. This limits innovation in governance, DeFi, and on-chain use cases.

[Proposal Summary] Supporting Documentation

Supporting links

• https://www.shutter.network/shutter-api
,
• https://www.ethtimecapsule.com/
,
• https://blog.shutter.network/permanent-shielded-voting-is-coming-to-snapshot/
,
• https://www.paddlebattle.auction/
,
• https://x.com/ShutterNetwork

[Proposal Summary] Project Dependencies

Does your project have any dependencies on other organizations, technical or otherwise?

No

Describe any dependencies or write 'No dependencies'

No dependencies

[Proposal Summary] Project Open Source

Will your project's outputs be fully open source?

Yes

Please provide details on the intellectual property (IP) status of your project outputs, including whether they will be released as open source or retained under another licence.

All Open Source, usually MIT

[Theme Selection] Theme

Please choose the most relevant theme and tag related to the outcomes of your proposal

Developer Tools

[Campaign Category] Category Questions

Describe what makes your idea innovative compared to what has been previously launched in the market (whether by you or others).

Shutter API's integration on Cardano would be a first of it’s kind privacy primitive and infrastructure. While Cardano's eUTXO model and focus on predictability reduce some MEV-related value extraction, it still faces challenges around information asymmetry and fairness in high-stakes applications like voting or trade ordering. Shutter innovates by delivering a developer-centric, trust-minimized threshold encryption service tailored specifically for Cardano, empowering builders through a plug-and-play "encryption-as-a-service" API to create apps that prioritize equity without the heavy lift of custom cryptography.

While Midnight Network introduces ZK privacy, there's no unified, plug-and-play API for threshold encryption. Cardano's ecosystem lacks ready-to-use tools for commit-reveal workflows, time-lock puzzles, or encrypted interactions, gaps that hinder innovation in governance, DeFi, and beyond.

We're leveraging Shutter's battle-tested core, already powering fair trading on Gnosis Chain and Shielded governance in DAOs to fit Cardano's unique architecture. This means developers can call a simple API for distributed key generation and threshold decryption, without maintaining infrastructure or trusting hardware enclaves (a common vulnerability in TEE-based systems). Our POC, a Sealed Bid Auction dApp, will demonstrate a real-world use case to host fair actions.

There is a wide set of use cases: sealed RFPs for transparent funding, private gaming without cheats, and time-locked content for creators. Cardano can power them all.

Shutter enables and democratizes privacy on Cardano, making it accessible and sustainable, fostering an ecosystem where fairness isn't an add-on but the default.

Describe what your prototype or MVP will demonstrate, and where it can be accessed.

Our MVP will demonstrate Shutter API's deployment as a core deliverable: a fully operational, plug-and-play encryption-as-a-service on Cardano, enabling any developer to integrate threshold encryption without custom infrastructure. This includes testnet and mainnet launches, with end-to-end functionality for distributed key generation, commit-reveal workflows, and secure decryption to ensure fair, privacy-preserving dApps.

In scope, it pairs the API rollout with comprehensive support, detailed documentation, step-by-step setup guides, and demonstration videos, empowering Cardano devs to add features like shielded interactions swiftly.

Additionally, we will launch a Sealed Bid Auction dApp as a pilot to showcase end-to-end threshold encryption on Cardano dApps and how seamless the implementation is..

We will also provide examples of broader applications like DEXs, voting apps, prediction markets, and time-locked content to inspire others to build private products on top of Cardano or integrate privacy on their dApp.

Describe realistic measures of success, ideally with on-chain metrics.

Key metrics in the first 9 months include:

Our goal is to get 3 dApps integrating Shutter API on Cardano, measured on-chain via unique contract addresses calling the API for encryption workflows (e.g., commit-reveal transactions). However, we can’t guarantee adoption at this point.

5-10 auctions using the Sealed Bid Auction dApp.

Off-chain complements like ≥8 NPS score from developer surveys will gauge usability, but on-chain data takes precedence for objectivity. These thresholds are achievable based on Shutter's Gnosis Chain traction, where similar integrations drove rapid uptake.

[Your Project and Solution] Solution

Please describe your proposed solution and how it addresses the problem

We will deploy, maintain, and support the Shutter API on Cardano, providing a plug-and-play, trust-minimized threshold encryption service to the Cardano developers. Furthermore, we will deploy a pilot of a Sealed Bid Auction dApp.

Shutter API allows developers to integrate commit-reveal workflows, time-lock encryption, and shielded interactions without building or maintaining their own cryptographic infrastructure. Instead of relying on trusted hardware or custom setups, developers can simply call the Shutter API to access distributed key generation, encryption, and threshold decryption coordinated by the Shutter key network.

This solution unlocks many use cases:

Shielded governance: Protect votes from premature influence with Shielded Voting integrated with Snapshot and Kleros. (https://www.shutter.network/shielded-voting))

Fair DeFi: Encrypted orders to prevent MEV and front-running. (https://www.shutter.network/shielded-trading))

Sealed-bid auctions: Bids revealed simultaneously, ensuring fairness. (https://www.paddlebattle.auction/))

Prediction markets & games: Moves or predictions hidden until reveal conditions are met. (https://www.ethtimecapsule.com/, https://shutter-predict.shutter.network/, https://rfp.shutter.network/ and https://hongbao.shutter.network/))

By integrating Shutter on Cardano, we give developers a critical privacy and fairness primitive, allowing them to focus on their core value propositions while improving user trust and enabling entirely new application categories.

[Your Project and Solution] Impact

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

The Shutter API on Cardano will:

Fill a current infrastructure gap with production-ready, privacy-preserving developer tooling.

Empower developers to build fairer, more secure governance and DeFi platforms.

Open new verticals like sealed-bid RFPs, encrypted gaming, and time-locked content delivery.

Impact Measurement:

≥ 3 dApps integrating Shutter API within 9 months post-launch.

≥ 8 NPS score from partner teams on API usability.

5-10 auctions using the Sealed Bid Auction dApp.

Sharing Outputs:

Open-source API, documentation, and example integrations published on GitHub.

Technical guides and case studies shared via Cardano developer channels.

Fully functional Sealed Bid Auction dApp.

[Your Project and Solution] Capabilities & Feasibility

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?

Experience:

Shutter is developed by brainbot GmbH, a team with over a decade of experience in Web3 infrastructure, including contributions to the original Ethereum Python client, Raiden Network, and Beamer Bridge. Since 2021, the team has specialized in threshold encryption, delivering:

Shielded Voting in Snapshot (Protecting 298K+ votes and default in some DAOs, like the Arbitrum DAO).

Shielded Trading on Gnosis Chain in partnership with the Gnosis team, Nethermind and Gateway.

Shutter API, powering auctions, predictions, and commit-reveal apps.

This is a mature product with over 4 years of development

Feasibility:

The API is already live on Gnosis Chain and integrated into production apps. Adapting it to Cardano is primarily about protocol compatibility, with no need to reinvent the cryptographic core.

[Milestones] Project Milestones

Milestone Title

Cardano Testnet Integration of Shutter API

Milestone Outputs

We will deploy a fully Cardano-compatible version of the Shutter API on the testnet, ensuring seamless support for core cryptographic functions, including distributed key generation, threshold encryption, and decryption processes.

A secondary output will be publishing a form to start collecting feedback on the testnet integration to start iterating quickly based on dev feedback.

Acceptance Criteria

The integration will be deemed successful upon executing multiple commit-reveal operations on the Cardano testnet, with encryption and reveal phases verified through a combination of automated scripts (e.g., unit tests simulating dApp interactions) and manual inspections (e.g., reviewing transaction logs for correct decryption thresholds). All flows must operate without errors, ensuring that encrypted data remains secure until the reveal condition is met.

Community testers may confirm usability, providing input to refine the API before advancing.

Evidence of Completion

Completion will be evidenced by a publicly accessible testnet deployment endpoint, detailed GitHub release notes outlining the integration changes and version updates, and a comprehensive demonstration video walking through the encryption-to-reveal process step-by-step. The video will include live examples of API calls, transaction simulations, and verification of outputs, shared via Cardano developer channels for transparency. Additionally, test logs and code snippets will be uploaded to the repository, allowing independent verification by the community.

Delivery Month

4

Cost

60000

Progress

30 %

Milestone Title

Developer Documentation & Example Integrations

Milestone Outputs

We will produce complete, user-friendly documentation covering Shutter API's features, alongside detailed setup guides for seamless integration into Cardano dApps. This will be complemented by example repositories demonstrating practical applications to empower developers to adopt threshold encryption.

Acceptance Criteria

Acceptance requires the publication of comprehensive documentation and setup guides. The examples must showcase a complete workflow, such as encrypting votes or bids and revealing them post-condition, verified through code reviews and test executions. Guides should include API endpoints, error handling, and best practices, ensuring developers can replicate integrations independently. Feedback from initial users will confirm clarity and completeness before approval.

Evidence of Completion

Evidence includes a public GitHub repository hosting the documentation, example code, and setup guides, all accessible online with clear navigation. The repository will feature versioned releases, commit histories detailing contributions, and integrated README files with step-by-step instructions. Screenshots or embedded demos within the docs will illustrate key integrations, and links to testnet interactions will allow verification. This transparent approach enables the Cardano community to review and build upon the materials, fostering broader adoption.

Delivery Month

5

Cost

30000

Progress

40 %

Milestone Title

Mainnet Launch

Milestone Outputs

Shutter API deployed on Cardano mainnet.

We will launch the Shutter API on Cardano's mainnet, providing a production-ready encryption-as-a-service that supports threshold decryption, distributed key management, and secure workflows for live dApps.

We will launch a second form to collect user feedback from the Mainnet deployment.

Acceptance Criteria

The launch will be accepted upon the activation of stable mainnet endpoints that facilitate full encryption and decryption operations, tested for reliability under simulated load conditions. Endpoints must respond correctly to API calls, with no failures in key generation or reveals, verified through automated monitoring tools and manual audits. Security checks will confirm trust-minimization, and initial integrations from the testnet phase will be migrated successfully.

Evidence of Completion

Mainnet endpoints.

Completion will be proven by publicly shared mainnet endpoints, accessible via API documentation with usage examples. GitHub updates will include deployment scripts and logs, while a launch announcement on Cardano forums and Shutter's channels will detail the rollout. Independent verifiers can test the endpoints directly, confirming functionality through sample transactions.

Delivery Month

7

Cost

50000

Progress

70 %

Milestone Title

Sealed Bid Auction dApp on Cardano

Milestone Outputs

We will build and deploy a fully functional Sealed Bid Auction dApp on Cardano mainnet as a pilot.

On the dApp anyone would be able to kick off an auction, define and describe what’s being auctioned, set minimum bids, define the submission deadline, the reveal unlock time, among other parameters.

This dApp integrates Shutter API fully, demonstrating threshold encryption in action through commit-reveal workflows and time-locked interactions. Open-source code will be provided to facilitate replication and extensions.

Acceptance Criteria

The built in-house dApp must be fully functional on Cardano mainnet, showcasing a complete encryption workflow. Evidence of the first auctions revealing the bids securely post-condition. Verifiications through automated tests for reliability and manual reviews for user experience.

Integration with Shutter API endpoints must handle real transactions without errors.

Evidence of Completion

Completion will be shown via a public GitHub repository containing the dApp's source code, deployment scripts, and integration details; a live mainnet deployment link for direct testing; and sample transaction logs demonstrating end-to-end functionality. These assets will be shared on Cardano developer forums, allowing independent verification and community experimentation.

Delivery Month

8

Cost

30000

Progress

90 %

Milestone Title

Project Close Out Report and Video

Milestone Outputs

We will produce a comprehensive Project Close Out Report detailing the entire project journey, including technical implementations, milestone achievements, challenges overcome, impact metrics (e.g., on-chain integrations and usage), and recommendations for future Shutter expansions on Cardano. Paired with this, a Project Close Out Video will narrate key highlights, demo the pilot dApp, and showcase API usability, aimed at educating the community on encryption-as-a-service benefits.

Acceptance Criteria

Acceptance requires a detailed, publicly accessible Close Out Report covering all project aspects with data-backed insights, and a professional Close Out Video. Both must incorporate on-chain metrics for objectivity, reflect community feedback, and align with grant guidelines for completeness.

Evidence of Completion

Evidence includes the published Close Out Report linked online with full text, visuals, and metric summaries; the Close Out Video; and announcements on Cardano and Shutter channels for accessibility. All materials will be archived in the project's GitHub for ongoing reference, enabling stakeholders to assess fulfillment and inspire similar initiatives. This comprehensive proof reinforces accountability and impact.

Delivery Month

9

Cost

30000

Progress

100 %

[Final Pitch] Budget & Costs

Please provide a cost breakdown of the proposed work and resources

The total budget request is 200,000 ADA, allocated as follows:

API Adaptation & Integration (110,000 ADA): Modify the Shutter API to ensure full compatibility with the Cardano ecosystem.

Use Case Development (50,000 ADA): Build a sealed-bid auction dApp pilot application showcasing Shutter API capabilities.

Documentation & Developer Support (25,000 ADA): Create comprehensive developer guides, host workshops, and provide onboarding support to early adopters.

Project Management & QA (15,000 ADA): Oversee coordination, quality assurance, and transparent reporting throughout the project lifecycle.

[Final Pitch] Value for Money

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

This project delivers key developer infrastructure that will remain available to the Cardano ecosystem long after the grant is completed. By integrating Shutter’s proven encryption technology, Cardano gains a trust-minimized, open-source privacy primitive that developers can plug into their dApps without needing deep cryptographic expertise or costly infrastructure.

The grant funds are directed toward clear, tangible outputs, the Cardano API adaptation, developer documentation, and an in-house demo dApp, ensuring that all deliverables are open-source public goods. The same technology is already in production on other chains, demonstrating its reliability and making the Cardano integration a low-risk, high-impact investment.

For the cost of this proposal, the Cardano community gets:

A ready-to-use encryption service for governance, DeFi, auctions, and more.

A sealed bid auction pilot dApp showcasing practical adoption paths for builders.

Open documentation and example code to speed up future integrations.

Compared to the resources and expertise individual teams would need to recreate similar capabilities, funding Shutter’s integration is significantly more capital efficient. It enables many future projects to launch fairer, privacy-preserving workflows at a low cost, creating compounding value for Cardano.

[Self-Assessment] Self-Assessment Checklist

I confirm that evidence of prior research, whitepaper, design, or proof-of-concept is provided.

Yes

I confirm that the proposal includes ecosystem research and uses the findings to either (a) justify its uniqueness over existing solutions or (b) demonstrate the value of its novel approach.

Yes

I confirm that the proposal demonstrates technical capability via verifiable in-house talent or a confirmed development partner (GitHub, LinkedIn, portfolio, etc.)

Yes

I confirm that the proposer and all team members are in good standing with prior Catalyst projects.

Yes

I confirm that the proposal clearly defines the problem and the value of the on-chain utility.

Yes

I confirm that the primary goal of the proposal is a working prototype deployed on at least a Cardano testnet.

Yes

I confirm that the proposal outlines a credible and clear technical plan and architecture.

Yes

I confirm that the budget and timeline (≤ 12 months) are realistic for the proposed work.

Yes

I confirm that the proposal includes a community engagement and feedback plan to amplify prototype adoption with the Cardano ecosystem.

Yes

I confirm that the budget is for future development only; excludes retroactive funding, incentives, giveaways, re-granting, or sub-treasuries.

Yes

[Required Acknowledgements] Consent & Confirmation

I Agree

Yes