Non-Custodian Vault

Introduction

In contrast to many existing BTC custody projects, BridgingFi's novel non-custody model is defined by its core principle: users retain complete control over their BTC assets. Within this framework, asset control is permanently held by the user, yet they are unable to unilaterally terminate the custody arrangement. This mechanism enables both the party providing BTC for custody and the party requiring it to operate without reliance on mutual trust or the involvement of any third-party intermediary.

Details

The vault is technically implemented using a Taproot output with two distinct script paths, as illustrated in the figure below.

• Multi-Sig Lock: This path is a 2-of-2 multi-signature composed of the user's public key and BridgingFi's public key. Both parties must provide a signature to unlock the output. This design ensures that neither party can unilaterally spend the funds, thereby guaranteeing the user's control.

• Fallback TimeLock: This path is secured by a timeLock and can only be spent by the user's public key after the specified time has elapsed. It serves as a final security measure, allowing the user to recover funds in the event of a complete network failure.