Sign-in with Bitcoin

Sign-in with Bitcoin (ic-siwb) is a developer library that enables native Bitcoin wallet authentication for applications on the Internet Computer (ICP). It allows users to log in to your app by signing a simple message with their Bitcoin wallet—no email, password, or third-party auth system required. This gives Bitcoin users a familiar, seamless login experience and lowers the barrier to onboarding for Bitcoin-native applications.

By integrating Sign-in with Bitcoin, developers can authenticate users directly from the wallets they already use and trust. The library supports signature verification and identity generation for popular Bitcoin wallets like Xverse, Leather, Unisat, OKX, and Phantom. This allows any ICP-based Bitcoin DeFi app to give users a login flow that feels native to the Bitcoin ecosystem.

The result is a login experience that's fast, decentralized, and wallet-centric—offering strong privacy guarantees and user control. For developers building Bitcoin apps on ICP, Sign-in with Bitcoin is a critical tool to align authentication with the expectations of Bitcoin users and to deliver a user experience that feels truly Bitcoin-native.

Learn more about the Sign-in with Bitcoin project and how to integrate it.