Bitcoin Wallet for Advanced Users

Abstract

This thesis presents the design and implementation of a mobile application for the Android platform aimed at advanced Bitcoin asset management. Its main features are support for multisignature transactions in an M-of-N scheme according to the BIP-48 and BIP-67 standards, and a coin control feature for manual selection of transaction outputs, allowing the user to optimize fees and preserve privacy. A key security element is the integration of the Trezor hardware wallet via the Trezor Connect protocol; private keys never leave the device. The PSBT format (BIP-174) is used to distribute partially signed transactions among cosigners; the application supports native SegWit addresses P2WP- KH and P2WSH. The backend is implemented as a set of microservices in Kotlin/Ktor, the frontend is a native Android application built with Jetpack Compose. Functionality was verified by unit tests of key components and by an end-to-end multisig scenario on the Bitcoin testnet.