X150-Valkyrie Wallet: One-Touch & Offline Pay, Mnemonic Safe

[Proposal setup] Proposal title

Please provide your proposal title

X150-Valkyrie Wallet: One-Touch & Offline Pay, Mnemonic Safe

[Proposal Summary] Budget Information

Enter the amount of funding you are requesting in ADA

100000

[Proposal Summary] Time

Please specify how many months you expect your project to last

12

[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?

Poor user habits, like saving mnemonics as screenshots or digital notes, risk wallet hacks on Cardano. The payment process is complex, and direct offline P2P transactions are not supported.

[Proposal Summary] Supporting Documentation

Supporting links

• https://github.com/sonson0910/X150-Valkyrie.git
,
• https://x.com/veneralab

[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?

No

License and Additional Information

The entire mobile application code for Android will be made public on GitHub under the MIT license, including all services, UI components, and utility functions. This ensures transparency, allows the community to conduct independent security audits, and encourages other developers to contribute or build upon the product, strengthening the entire ecosystem.

[Theme Selection] Theme

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

Wallet

[Campaign Category] Category Questions

Describe what makes your idea innovative compared to what has been previously funded (whether by you or others).

The X150-Valkyrie Wallet brings innovations that have never been seen in existing Cardano wallets. In addition to the basic functions of other wallets, we focus on developing more outstanding features including offline payments, one-touch payments, and exclusive mnemonic attack resistance security mechanisms. These new features not only enhance the user experience but also bring superior convenience and security to users on the Cardano platform.

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

Our MVP demonstrates all core functions of a Cardano wallet, including wallet creation and restoration, secure mnemonic encryption, biometric authentication, ADA transfers, NFT management, DeFi staking, and Guardian Recovery.

Beyond these essentials, Valkyrie introduces unique innovations: offline payments, one-touch payment, and a new mnemonic attack resistance mechanism.

The MVP is fully open-source and can be accessed via our GitHub repository, with a downloadable Android APK demo.

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

Our success will be measured on-chain during the testnet phase through:

• Number of wallets created using the X150-Valkyrie wallet.
• Transaction volume executed on-chain, reflecting real usage.
• Level of active wallet usage (recurring interactions, not just one-time installs).
• Payments conducted via unique features, such as offline transactions and one-touch payments.

These metrics will clearly demonstrate adoption, usability, and the distinct value our wallet brings to the Cardano ecosystem.

[Your Project and Solution] Solution

Please describe your proposed solution and how it addresses the problem

In the overmpll blockchmpin ecosystem - and Cardano in particular - mobile wallets are a critical tool for users to store, manage, and transact assets. However, current solutions force users to choose between convenience and security, with no real solution that balances both. This leads to three major problem areas:

• Security limitations:
  • Exposure of private keys and mnemonics: Most mobile wallets require users to record their recovery phrases (mnemonics) in raw form. In practice, many users store mnemonics by taking screenshots, writing notes in memo apps, or saving them in unencrypted files. This exposes assets to theft if the device or data is compromised.
  • Lack of multi-layered security: Many wallets do not support biometric authentication (fingerprint, Face ID, etc.), multi-signature, or advanced attack-resistant mechanisms, leaving asset protection dependent on a single layer of security (password or PIN).
• No offline transaction signing (Air-Gapped): Current wallets cannot perform offline transactions, making it difficult for users to pay directly at stores or transact nearby in poor or no internet conditions. Transactions cannot be completed instantly, causing inconvenience for both buyers and sellers.
• Complex payment process: To initiate a transaction, users must manually input the recipient address and token pount. This manual process leads to poor user experience and risks errors such as sending tokens to the wrong address.

All of the above problems will bring users limitations:

• New users: Prone to mistakes in mnemonic storage, leading to irreversible asset loss.
• Advanced users/enterprises: Lack reliable tools for secure transactions, especially when multi-sig, offline signing, or complex portfolio management is needed.
• Cardano ecosystem: Slows user adoption and limits advanced use cases like secure offline payments, multi-signature contracts, and advanced digital asset management - making Cardano less competitive compared to other blockchain networks with similar features.

These limitations have driven us to develop X150‑Valkyrie - an advanced wallet that, beyond the basic features of existing Cardano wallets, adds offline transaction capabilities, high-level security, and one-touch payment integration for user convenience.

1. Optimized security payment

• Mnemonic attack resistance: We use a 24→36 mnemonic security mechanism (Password-Locked). Valkyrie transforms the original 24-word seed into a 36-word encrypted mnemonic, encoding entropy with a password-derived keystrep and separating the encrypted 24-word entropy from a 12-word salt. Only the 36-word mnemonic is displayed/stored; the original seed never exists on the device and can only be recovered with the correct password. Users must have the password, the 36-word mnemonic, and the Valkyrie app to restore the wallet and transact. Data is encrypted using AES‑256‑CBC with PBKDF2 (100k iterations), virtually eliminating mnemonic exposure risk.
• Offline payment (Air-gapped signing): X150‑Valkyrie allows users to create and sign transactions entirely offline, then transmit signed data to the seller’s device via Bluetooth Low Energy (BLE). Transactions are chunked with integrity checks (CRC, ACK/RESEND) and queued securely, automatically broadcasting to the blockchain once internet is available. QR codes are provided as a fallback when BLE is limited. This enables direct payments at stores or between nearby partners without relying on instant internet connectivity - ensuring convenience and security for both parties.
• One-touch payment: Users can pay ADA with a single tap after unlocking the wallet via biometric authentication. At supported payment terminals, the device uses an integrated NFC chip for short-range wireless communication. When the device is brought near the NFC reader, the ADA transaction is automatically initiated and processed via the linked wallet, ensuring speed and maximum convenience. This process is protected by multi-layered security:
  • Biometric authentication before payment activation
  • Transaction data encryption per Cardano and international payment standards
  • Instant blockchain confirmation for transparency and fraud prevention
• Secure enclave key storage: Uses built-in smartphone hardware security (Secure Enclave/TEE) to protect private keys, combined with AES-256 encryption and biometric authentication (fingerprint, FaceID).

2. Advanced user center:

• DeFi & staking dashboard: Manage staking and interact with DeFi protocols
• Portfolio analytics: Provide asset performance insights
• Transaction alerts & analysis: Integrates WhaleTrack to monitor whale wallet activity, analyze market trends, and send real-time alerts
• AI stake pool performance tracker: A simple AI tool to track Cardano stake pool performance, including metrics like delegator count, rewards, and fees. It analyzes data and suggests pools based on user priorities—e.g., maximizing returns or supporting smaller pools.

3. Intuitive user experience :Advanced features are integrated into a simple, user-friendly interface, allowing even beginners to perform complex tasks like setting up multi-sig or making offline and one-touch payments.

Expected impact

• New users: Can use the wallet securely without needing deep security knowledge, thanks to Beginner Mode and automated protection mechanisms.
• Advanced users & enterprises: Equipped with full advanced features like multi-sig, offline signing, DeFi/NFT integration, and AI-powered analytics.
• Cardano ecosystem: Accelerates user adoption, expands complex use cases, and strengthens Cardano’s image as a secure, user-friendly, and innovative platform.

Development strategy

To build a truly complete product that delivers optimal performance and security, the project will undergo multiple complex development phases. Therefore, we aim to break development into stages and seek support and funding from the Cardano community. We hope to soon deliver a finished product that serves users effectively.

Phase 1 – MVP on Testnet

In the first phase, we will focus on deploying the most essential components to create an MVP version with all core functionalities. This version will be launched on the testnet to reduce costs, ensure safe testing, and quickly gather community feedback.

Key features planned for Phase 1:

• Core wallet:
  • Security & key management: Full personal wallet management with mnemonic encryption and biometric authentication
  • Transaction management: Receive/send tokens/coins, transaction history
  • Asset management: Display balances & values, manage tokens and NFTs
  • Staking management:Delegate to pools, track rewards, withdraw rewards, undelegate
• Advanced features:
  • Offline payment: Mechanism for users to create and sign transactions offline, transmit via BLE with chunking, integrity checks, and secure queuing. Signed transactions are auto-broadcasted when internet is available. QR fallback included for BLE limitations.
  • One-touch payment: Mechanism for users to pay ADA with a single tap via NFC chip. Unlock wallet with biometrics, bring device near NFC reader at point of sale, and transaction is automatically initiated and confirmed on the blockchain.

Solution summary

In Phase 1, we focus on building an MVP on the testnet with the core components above. This approach ensures optimal resource use, delivers real-world testing results quickly, and lays a solid foundation for scaling to mainnet in Phase 2. From the completed Phase 1 foundation, advanced features and deeper ecosystem integration will be developed in subsequent phases (Phase 2 & 3), aiming for a comprehensive, secure, and utility-rich solution that brings long-term value to the Cardano community.

[Your Project and Solution] Impact

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

X150-Valkyrie will deliver clear and measurable value

• Enhancing user security: Bringing hardware wallet-level security to mobile for free, reducing the risk of asset loss.
• Increasing participation from advanced users: Tools like multi-signature and asset analytics encourage more active community engagement.
• Reliable public Open-source product: An open-source wallet, audited and positioned as foundational infrastructure.

Impact measurement:

• Completion and publication of security audit report
• Positive user feedback
• Usage of advanced features, measured via optional analytics

X150-Valkyrie directly addresses a critical issue in the Cardano ecosystem

The vulnerability of recovery phrases (mnemonics) and the lack of hardware-level security solutions for mobile users are major concerns. By implementing a proprietary Mnemonic Attack Resistance Mechanism and offering a wallet with hardware-grade security completely free, the project will deliver clear, measurable positive impact.

Our project aims to solve current limitations in blockchain wallet experiences-especially on Cardano-where existing wallets still pose security risks, lack mnemonic attack resistance mechanisms, and require users to protect their mnemonics manually. Payment solutions are not yet optimized for general users; for example, no wallet currently supports one-touch payments like traditional wallets, nor do they support direct peer-to-peer payments in environments with poor or no internet connectivity. This causes significant inconvenience and frustration for users. Therefore, we have implemented an offline payment module to address these challenges. Issues include complex operations, lack of standards for offline transactions, and poor user experience.

By developing a demo wallet application on android, we deliver the following positive impacts

• Paving the way for user-friendly Cardano wallets: The app will integrate core features such as secure wallet management with encrypted mnemonic protection to help users defend against mnemonic attacks-solving the hidden risks of manual mnemonic storage in traditional wallets. It will also support offline payments and one-touch payments. These optimized features will offer superior convenience compared to current wallet solutions.
• Creating practical payment experiences for users: Implementing offline and one-touch payments not only enhances user experience but also demonstrates Cardano’s feasibility in real-world scenarios (e.g., payments in areas without internet, fast transactions at retail points). This expands Cardano’s blockchain applications beyond the traditional crypto community.
• Increasing potential to attract new users: By offering a wallet with superior features not yet available in many other ecosystems, the project creates a competitive advantage, attracting more users and expanding the community for Cardano-based products.
• Aligning with Cardano’s development direction: The project contributes to increasing the number of applications and products with advanced, trend-setting features on Cardano, expanding real-world use cases and promoting Cardano as a platform capable of competing directly with popular blockchain networks in the wallet and payment space, such as Ethereum or Solana.

KPIs – Success metrics

• Downloads & usage: Achieve at least 100 downloads and demo trials within the first 6 months.
• Community engagement: Attract at least 50 views on tutorial videos and receive a minimum of 20 responses from developers and users.
• Activity on demo app: Record the number of trial users, newly created wallets, and transactions executed on the developed mobile wallet demo.

Sharing results with the community

We will share project outcomes with the community through the following channels:

• Public release of open-source code on GitHub with documentation and tutorial videos
• Progress reporting via PoA (Proof of Achievement)
• Publishing updates on social media and Cardano forums
• Participating in Cardano events/conferences to present and gather feedback
• Hosting online workshops to support developers in integrating and expanding the solution

[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?

Our team is composed of seasoned developers and blockchain educators with a strong background in AI, Cardano, and decentralized technology. We have consistently secured funding from multiple Catalyst rounds, demonstrating our ability to execute innovative projects within the Cardano ecosystem. Some of our notable projects include:

The Moderntensor project won 1st prize in the Cardano Blockchain Hackathon 2025.

Our project funded:

• Fund 10 Funded Project: "🇻🇳 Vietnam Cardano Catalyst - NFT Exchange testing and development environment helps young people approach with the Web3.0 platform"
• Fund 11 Funded Projects:
• "Dualtarget for ADA-Holders (Staking and increasing assets) with a decentralized automated trading bot"
• "🇻🇳 The Complete Aiken Course Cardano: From Zero to Expert!"
• Fund 12 Funded Project: "Open source dynamic assets (Token/NFT) generator (CIP68)"
• Fund 13 Funded Project: “[BUTC] Fueling Growth: Cardano Hackathons to Inspire Startup Success”

These achievements not only provide a solid foundation for the current proposal but also affirm our capacity to effectively manage funded initiatives and deliver tangible value to the Cardano ecosystem.

Comprehensive blockchain expertise

Our team possesses deep knowledge and practical experience in blockchain development, AI, and decentralized solutions. Beyond project execution, we have contributed to Cardano through practical implementations and recognized research, such as:

• Article 1: "Students Scientific Research with Cardano Blockchain"
• Article 2: "Students Scientific Research with Cardano Blockchain"
• Article 3: "Scientific research results of students of the University of Transport and Communications 2024"
• Article 4: "Cardano Blockchain Hackathon Vietnam 2024”
• This blend of technical skill and active engagement in the Cardano community equips us with the competence and vision to successfully execute this project.

Validation and collaboration

The project's feasibility will be demonstrated through a Minimum Viable Product (MVP), incorporating both quantitative and qualitative measurement methods:

Quantitative metrics:

• Tracking the number of module upgrades and contributions via GitHub.
• Monitoring task completion rates on Trello.
• Measuring adoption through the number of active users on the platform.

Qualitative assessment:

• Conducting user satisfaction surveys to refine the product.
• Assessing stakeholder interest during project presentations.
• Close collaboration with the Cardano community and relevant stakeholders ensures our solution is practical, meets user needs, and aligns with the latest technological advancements.

Financial management and accountability

We are committed to transparent and effective financial management through the following strategies:

• Detailed budget planning: Clear allocation of resources for development, operations, and marketing.
• Transparent cost tracking: Maintaining auditable records of all expenditures.
• Periodic reporting: Providing regular updates to assess financial performance and guide strategic adjustments.
• Supported by our team's academic background and project management experience, we adhere to strict budgetary discipline and the highest standards of transparency.
• Amplifying impact and open-source commitment

We are not only focused on project completion but also on amplifying its impact through open-source contributions and community engagement. Our tools and solutions will be made publicly available, fostering decentralized innovation and promoting widespread blockchain adoption. Transparency and communication are our guiding principles through open dialogue with stakeholders, regular progress updates, and a collaborative environment, we ensure all parties are engaged in the project's success.

We invite Catalyst to join us in shaping the future of decentralized innovation.

[Milestones] Project Milestones

Milestone Title

System design & initialization

Milestone Outputs

• Market research:
  • Survey on current payment methods in crypto
  • Survey on payment experience outside crypto (real-world)
  • Survey on user needs & behavior
  • Survey on barriers & opportunities for application
• Technical requirements document: functional & non-functional requirements
• System architecture design
• UI/UX Design (Android app)
• Public GitHub Initialization: README, MIT license

Acceptance Criteria

• Completed survey report covering all 4 research areas listed in Outputs
• System architecture diagram clearly describing system components, data flow, and relationships
• Technical requirements document including:
  • Functional requirements for the system
  • Non-functional requirements such as security, performance, scalability
• UI/UX design for the Android app, including all interface components and user flows covering both Core features and Advanced features of the wallet
• Public GitHub repository initialized with README, and MIT license

Evidence of Completion

• Link to survey report (PDF)
• Link to system architecture diagram
• Link to Technical requirements document (PDF)
• Link to Figma file containing UI/UX design of the application
• Link to public GitHub repository containing MIT License, README

Delivery Month

2

Cost

10000

Progress

10 %

Milestone Title

Core development phase 1 (Key management & security, transaction management)

Milestone Outputs

• Key management & security development: Create/restore wallet, encrypt mnemonic from 24 to 36 words, biometric authentication, auto-lock
• Transaction management development: Send/receive tokens, UTXO handling, fee estimation, transaction signing, address verification, transaction history
• Unit testing: Full unit tests for each feature
• UI development: User interface for the above two features

Acceptance Criteria

• Key management & security module developed with stable functionality on testnet: wallet creation/restoration, mnemonic encryption with attack resistance mechanism, biometric authentication, and auto-lock
• Transaction basic management module developed with successful functionality on testnet: send/receive tokens, UTXO handling, fee estimation, transaction signing, address verification
• 100% unit test cases executed successfully
• Android interface fully supports all features described in the core key management & security and transaction management outputs

Evidence of Completion

• Link to GitHub commit containing complete source code of the modules
• Link to test report (PDF) showing 100% test case pass rate
• Link to public demo video showcasing the features of the modules described in the output

Delivery Month

5

Cost

28000

Progress

40 %

Milestone Title

Core development phase 2 (Assets management + staking)

Milestone Outputs

• Assets management development: Display balances & values, manage tokens/NFTs
• Staking management development: Delegate to pools, track rewards, withdraw rewards, undelegate
• Unit testing: Full unit tests for each feature
• UI development: User interface for the above two features

Acceptance Criteria

• Assets management developed with support for displaying asset balances and values, syncing data directly from the blockchain, converting to fiat (USD, EUR, VND…), and managing tokens and NFTs with detailed views of token quantities and NFT collections
• Staking management developed with successful functionality on testnet: delegation to pools, reward tracking, reward withdrawal, undelegation
• 100% unit test cases executed successfully
• Android interface fully supports both features described in the assets management and staking management outputs

Evidence of Completion

• Link to GitHub commit containing complete source code of the modules
• Link to test report (PDF) showing 100% test case pass rate
• Link to public demo video showcasing the features of the modules described in the assets management and staking management outputs

Delivery Month

8

Cost

17000

Progress

60 %

Milestone Title

Advanced development (Offline payment, One-touch payment)

Milestone Outputs

• Offline payment module development: Create & sign transactions offline, transmit data via Bluetooth, set up secure queue in wallet, auto-send when internet is available, add QR code fallback option
• One-touch payment module development: NFC payment with one touch, biometric authentication before payment, transaction processing & encryption according to Cardano standards
• Unit testing: Full unit tests for each feature
• UI development: User interface for both modules

Acceptance Criteria

• Offline payment module developed with successful functionality on testnet: create & sign transactions offline, transmit data via Bluetooth, set up secure queue in wallet, auto-send when internet is available, QR code fallback option
• One-touch payment module developed with successful functionality on testnet: NFC payment with one touch, biometric authentication before payment, transaction processing & encryption according to Cardano standards
• 100% unit test cases executed successfully
• Android interface fully supports all features described in the Offline payment and One-touch payment outputs

Evidence of Completion

• Link to GitHub commit containing complete source code of the modules
• Test report (PDF) showing 100% test case pass rate
• Link to public demo video showcasing the features of the two modules described in the output

Delivery Month

11

Cost

30000

Progress

80 %

Milestone Title

System integration & demo android release

Milestone Outputs

• Integrate all modules (Core features and Advance features) into a complete android application
• Perform integration testing and system testing with end-to-end scenarios covering features of all modules
• Deploy public demo APK on testnet for community installation and testing
• Conduct user survey on product feature experience and collect feedback for improvement
• Improve product based on feedback
• Write user guide (PDF)
• Close-out Report
• Close-out Video

Acceptance Criteria

• Android application fully integrates all modules and runs stably on Cardano testnet
• All end-to-end scenarios tested successfully on android devices
• Interface meets minimum consistency standards (Material Design) and is user-friendly
• Demo APK installable and usable by community testers
• Minimum of 50 users surveyed for product feature experience and feedback collected
• Product improved based on feedback
• Clear user guide document with demo video
• Close-out report includes content as required by the community
• Close-out video includes content as required by the community

Evidence of Completion

• Link to GitHub repository containing fully integrated source code of all modules
• Test report (PDF) of end-to-end scenarios
• Link to public demo APK file
• Link to Google Sheet containing list of feedback from test users
• Product improvement report based on feedback
• Demo video of full features
• User guide (PDF)
• Link to public close-out report
• Link to public close-out video

Delivery Month

12

Cost

15000

Progress

100 %

[Final Pitch] Budget & Costs

Please provide a cost breakdown of the proposed work and resources

SUMMARY

Milestone 1: Design & initialization

Estimated cost for this phase: 10000 ADA ⇔ 10%

Milestone 2: Core development phase 1 (Key management & security, transaction management)

Estimated cost for this phase: 28000 ADA ⇔ 28%

Milestone 3: Core development phase 2 (Assets management + staking)

Estimated cost for this phase: 17000 ADA ⇔ 17%

Milestone 4: Advanced feature development (Offline payment, One-touch payment)

Estimated cost for this phase: 30000 ADA ⇔ 30%

Milestone 5: System integration & Android demo release on Testnet

Estimated cost for this phase: 15000 ADA ⇔ 15%

Total Costs: 100000 ADA

For more detail budget, following by the link:

https://docs.google.com/spreadsheets/d/164#gid=921977964MayOhn7HxqkEKOeG2ulsJC-wfHbzFlA0QPj0t5Vqmvo/edit?usp=sharing

[Final Pitch] Value for Money

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

With 100,000 ADA, the requested funding is fully justified by the immense value this project will deliver to the community.

The project creates foundational public infrastructure. A free, open-source, high-security mobile wallet will elevate Cardano’s value for all users. The majority of the cost is allocated to security auditing, directly protecting the community’s assets. With a small investment, the community receives a complete, audited product that can prevent millions of USD in potential losses, raising the security standards and credibility of the ecosystem.

The proposed budget for the project is entirely reasonable when placed in the context of current labor market conditions and blockchain software development costs. Building a secure, open-source, and free mobile wallet for the community requires a team of engineers with extensive experience in blockchain, security, and infrastructure. The proposed cost has been carefully calculated to reflect market realities, ensuring it is sufficient to attract and retain high-quality personnel, while remaining within the average range compared to similar Web3 projects.

Importantly, the majority of the budget is allocated directly to security auditing and infrastructure operations-two key factors in protecting user assets. This cost is not only technical but also a strategic investment to prevent risks that could result in millions of USD in losses for the community if a security incident occurs. Prioritizing the budget for auditing demonstrates the project’s commitment to placing user safety and trust at the forefront.

With a relatively small investment compared to the potential value the project delivers, the community will receive a complete product, professionally audited, accessible to all users, and fully open-source for community verification, contribution, and expansion. This project not only provides a practical tool for safer and more convenient Cardano usage, but also raises the overall security standards and reputation of the entire ecosystem.

The funds granted by the community are used transparently, reasonably, and deliver tremendous value-not only by creating an immediately useful product for users, but also by reinforcing trust, minimizing risk, and ensuring the long-term sustainable growth of Cardano.

[Required Acknowledgements] Consent & Confirmation

Terms and Conditions:

Yes