CoinfyWallet - A Bitcoin & Lightning Wallet

This project is a fork of BlueWallet, a popular Bitcoin wallet for iOS and Android. This project was submitted as a result of a hackathon on Bitcoin++ 2025 - Florianopolis, Brazil.

Changes on BlueWallet source code:

• The main logic changes were implemented on class/wallets/legacy-wallet.ts:

There are two algorithms used to select coins: coinSelectSplit and coinSelect. We added a param coinfyLambda that, if present, changes the selection algorithm to coinSelectCoinfy.

coinSelectCoinfy split the UTXOs based on its memo, which is stored on Wallet app, not on blockchain.
If memo contains the dirty keyword, the UTXO is added on dirty UTXOs set.
If memo contains the clean keyword, the UTXO is added on clean UTXOs set.
If memo contains the none keyword or memo is empty, the UTXO is added on none UTXOs set.

Example of a list of UTXO with memos:

Then coinSelectCoinfy algorithm tries to select only safe UTXOs: clean and none using the coinSelect algorithm. If they contain enough balance, the algorithm creates the new transaction and returns it.

The next step is trying to select only dirty UTXOs using the coinSelect algorithm. If they contain enough balance, the algorithm creates the new transaction and returns it.

Example of a scenario without mixed UTXOs:

Otherwise, it will need to mix safe and dirty UTXOs. If they contain enough balance, the algorithm creates the new transaction and returns it, adding a warn message about UTXO mixing and informing the amount of clean sats necessary to be added on wallet in order to enable not mixing them.

Example of a scenario with mixed UTXOs:

• There are many design changes on the files of components folder
• And finally on the screen/send/SendDetails.tsx screen, the graphic changes were made on create the UTXO mixing warn and a button that will open the Privacy configuration screen, which will gather the params necessary for Bitcoin Coin selection with leverage.