# 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.