AI disclosure: AI tools were used to assist with parts of the code, documentation and graphics of this item. The author directed the work and reviewed the code before release.

What it does

• NFC card confirms every signature (EVM, Solana, Bitcoin, WalletConnect)
• Card gate: require the card to open the app, for transactions, or both; 72-hour lost-card switch-off checked against network time
• Card roles Owner / Backup / Spender
• Spender daily limits per chain (rolling 24h, native coin, enforced by the app on this phone)
• Tap to pay / share address: public receive addresses on the card (record mikodes.com:nfcaddr), 'Tap recipient's card' in Send
• PIN-encrypted seed backup on the card (record mikodes.com:nfcseed, Argon2id + AES-256-GCM)
• Card pairing, card list, card activity log
• Native NFC bridges (Core NFC on iOS, reader mode on Android) and universal/app links from the card

You need

• Flutter >=3.29.0 (developed with 3.41)
• Dart SDK nfc_crypto '>=3.2.0 <4.0.0'; cryptocard_wallet and nfc_recovery ^3.11.1
• iOS iOS 15.5+ (nfc_crypto), iOS 15.0+ (cryptocard_wallet, nfc_recovery); Xcode 16+; iPhone XS or newer for NFC
• Android compileSdk/targetSdk 36; minSdk = Flutter default (24) for all three; NFC-capable phone
• Python (Card Studio) 3.10+; pyscard>=2.0, argon2-cffi>=23.1, cryptography>=42; optional pywebview>=5