Cardano Wallet powered by 300

Deine ADA. Dein Staking. Deine Stimme.

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Preface: The following questionnaire was written by Codex based on the documentation and then edited by me.

Before that, I would like to highlight that German culture is very conservative from a financial perspective. My intention is to give users the option to stake ADA through a user-friendly and familiar interface.

My financial benefit comes from users staking with my SPO, which allows me to offer the tool for free. In addition, none of the current Cardano wallets offer recovery options through Google, email, GitHub, LinkedIn, or similar services. If a German user sees a 24-word recovery phrase, they will often simply close the app. P.S. Codex works great.

Inspiration

Cardano offers staking, governance, and true self-custody, but many people still find wallets, recovery phrases, stake pools, and DReps difficult to understand.

I created a Cardano Super Light Wallet to make these features accessible to German-speaking users - especially adults aged 30–65 who value familiar, straightforward and simple interfaces.

Our goal is not to present crypto as a savings account or guaranteed pension. We want to help users to onboard on Cardano make their own decisions.

What it does

Cardano Wallet powered by 300 is a super lightweight, non-custodial Cardano hot wallet. Users can:

  • Create a new wallet with a 15 or 24-word recovery phrase in one click.
  • Restore an existing wallet using 15 or 24 words
  • Protect the local wallet with a six-digit app code
  • View ADA balances, native assets, rewards, and delegation status
  • Display and copy a receiving address with a QR code
  • Prepare, review, sign, and submit ADA transactions (in production)
  • Delegate ADA to my Cardano stake pool
  • Delegate governance power to a DRep
  • Review fees, deposits, network, recipient, Pool ID, and DRep ID before signing

The app transparently recommends Pool 300 and DRep Wolfoden, but never delegates automatically. Staking and governance remain two independent choices that require explicit confirmation.

How we built it

We built the mobile application with:

  • React Native and Expo for iOS and Android
  • TypeScript for safer application logic
  • Cardano Serialization Library mobile bindings for CIP-1852 key derivation, transaction construction, certificates, and signing
  • Koios REST API for public UTxO, rewards, pool, DRep, and protocol data (will be changed to Cexplorer.io API)
  • Zustand for local application state
  • Zod for strict network-response validation
  • XChaCha20-Poly1305 for local recovery-phrase encryption
  • PBKDF2-SHA256 and a device-bound secret for local key protection
  • Expo SecureStore and encrypted local storage

Before signing, the app independently verifies the transaction body against what the user saw on screen. It checks inputs, recipient, amount, fee, change outputs, certificates, stake credentials, Pool ID, and DRep selection.

Challenges we ran into

  • Securely storing a recovery phrase on an internet-connected device
  • Keeping private keys completely local
  • Handling native mobile dependencies across iOS and Android
  • Supporting wallet recovery beyond a fixed address-discovery window
  • Using Google Auth, Apple Account, E-Mail to identify Wallet users and store recovery Phrases securly so user don´t have to worrie about Seed Phrases

We intentionally disabled Mainnet signing in the current production profile until the native bridge, address discovery, device testing, and external security audit are complete.

Accomplishments that we're proud of

We built a complete German-language mobile wallet foundation instead of only creating a UI prototype. The project currently includes:

  • Full wallet creation and restoration flows -Local encrypted recovery-phrase storage
  • ADA receiving and transaction-review interfaces
  • Stake-pool and DRep delegation flows
  • Protection against an injected attacker-controlled change address
  • Explicit Pool and DRep consent without hidden preselection
  • Android Target API 36 and iOS deployment configuration
  • App Store and Google Play metadata and assets
  • Successful Android native prebuild and Hermes bundle generation

Codex also verified Pool 300 and DRep Wolfoden against current on-chain data during development.

What we learned

Building a wallet is not only about generating keys and submitting transactions. The most important work happens around trust, understandable consent, transaction integrity, recovery, and honest communication.

We learned that:

  • Every transaction must be verified immediately before signing
  • A successful build is not the same as a secure Mainnet release
  • Crypto and functions doesn´t interest the user. It just has to work.

What's next for Cardano Wallet powered by 300

Our next milestones are:

  1. Implement dynamic CIP-1852 account and address discovery
  2. Upgrade or audit the native Cardano serialization bridge
  3. Complete independent security and cryptography reviews
  4. Run full Preprod tests on real iOS and Android devices
  5. Add reproducible signed release builds
  6. Publish final support, privacy, security, and legal pages
  7. Conduct a closed beta with German-speaking users aged 30–65
  8. Improve accessibility per one-click usage
  9. Launch a controlled Mainnet pilot after all release gates are complete
  10. Explore a separately audited CIP-30 or WalletConnect integration
  11. Google, Email, Apple Account verification without holding keys to securly restore lost accounts

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