🧱 Feature Plan: Flow Wallet Kit Core Architecture

[lmcmz]

📘 Overview

The Flow Wallet Kit is intended to handle all core wallet functionalities required to interact with the Flow blockchain, including Flow-EVM. This issue outlines the complete feature plan, broken down into modular components for implementation.

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🗂️ TODO Breakdown

1. 🔐 Storage Protocol

• Implement a storage protocol for securely handling keys and other sensitive data.
• Support secure storage backends (e.g., Keychain, Secure Enclave, iCloud file system).

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2. 🔑 Key Protocol

• Implement a key protocol to support multiple types of private keys.
• Implement the following key providers:
  • Secure Element Key Provider
  • Private Key Provider
  • Seed Phrase Key Provider

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3. 👛 Wallet

• Define and support three wallet types:
  • Watch Wallet: initialized with an address only.
  • Key Wallet: initialized with a private key or seed phrase.
  • Proxy Wallet: backed by external devices like Ledger.
• On initialization (Key Wallet), lookup all related on-chain accounts using a key indexer API.
• Support multiple accounts per wallet across different networks.

class Wallet {
    var accounts: [Flow.Network: [Flow.Account]]
}

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4. 🧾 Account

• Implement support for Cadence accounts on the Flow blockchain.
• Support multiple public keys linked to a wallet's signing keys.
• Accounts should act as transaction signers.
• Accounts should be able to fetch and manage:
  • VM accounts (currently EVM only)
  • Child accounts

class Account: FlowSigner {
    var coa: COAccount?
    var child: [ChildAccount]
}

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5. 🧬 Multi-VM Account

• Fetch and manage VM accounts associated with the main account.
• Currently only EVM (COA) is supported.
• Design should support additional VM types in the future.

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6. 👶 Child Account

• Fetch all child accounts linked to a main Flow account.
• Retrieve permissions related to FT and NFT access for each child account.

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7. 💰 Token Balance

• Query FT/NFT balances for:
  • Flow accounts
  • Flow-EVM accounts
• Handle mixed address token balance queries across both environments.

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8. 📦 Backup

• Support multiple backup types:
  • Device backup
  • Seed phrase backup
• Implement a backup protocol.
• Add support for cloud backup providers:
  • Google Drive
  • iCloud
  • Dropbox

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9. 🌐 FCL & WalletConnect Support

• Support in-app browser injection for:
  • Flow
  • Flow-EVM
• Handle WalletConnect requests for:
  • Flow
  • Flow-EVM

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📌 Notes

• All modules should be modular, secure, and independently testable.
• Ensure support for extensibility (e.g., new VM types, more backup providers).
• Prioritize seamless integration with Flow ecosystem tools and developer experience.