# Custody Safe ## Secure, Fee‑Free Bitcoin Self‑Custody *Move your Bitcoin from SmashFi to your own wallet — securely and fee-free.* ## 1. What Is Custody Safe? Custody Safe is SmashFi’s non‑custodial Bitcoin wallet powered by Multi-Party Computation (MPC) technology. It allows you to hold full control of your Bitcoin without seed phrases, and enables fee-free transfers from your SmashFi account under certain conditions. ## 2. Why Choose Custody Safe? * **Own Your Bitcoin**\ You retain your private keys – SmashFi does *not* custody your BTC, removing counterparty risk. * **No Seed Phrases**\ Access your wallet via a passphrase and a backup key; no mnemonic needed. * **Zero-Fee Transfers**\ Enjoy fee-free Bitcoin withdrawals when you move BTC purchased via Auto-Buy, Boost, or Swap. SmashFi covers these fees—and limits apply based on time period.\ Transfers from external wallets may still incur standard network fees. * **Easy Recovery & Backup**\ If you lose your device, use your **Backup Key** to restore access—without compromising your security. SmashFi or Fireblocks *cannot* access your BTC. * **Share Access with Trusted People**\ Add multiple devices (phone, tablet, PC), or invite trusted family/friends to share wallet access (each has their own key share). Even in emergencies, your BTC stays recoverable. ## 3. How Custody Safe Works * Built with 2-of-2 MPC technology: One key share on your device + one encrypted share on Fireblocks server → both required to sign transactions → There is no single point of failure or custodial risk. * Off-chain signature scheme ensures no public exposure like multi-signature wallets. * Transactions require both device and server signature → SmashFi/Fireblocks cannot move your BTC without your participation. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://how.smashfi.me/custody-safe.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.