Take Bitcoin Savings Seriously

Frostsnap is a security system that keeps your life savings outside of your home. In a sleek convenient form factor that presents the power of multisignature security.

Frostsnap leverages advanced cryptography to push the frontier of trustless hardware and security capabilities. Devices are not trusted to generate keys on their own, with your phone or laptop participating in key generation to add entropy and verify correctness.

• Easy setup: Devices connect in a daisy-chain and follow strict verifying and confirmation protocols
• Simple Recovery: Simple recovery with threshold number of devices and backups, no descriptor metadata gotchas.
• Lower multisig fees: Same transaction costs as regular wallets
• Privacy: Multisig wallets look identical to single-signature wallets on-chain
• Flexibility: Ability to add/remove signers, create additional policies (coming soon)

Each Frostsnap device is backed up independently with its own seed phrase. This seedphrase can be restored onto another device.

The beauty of threshold multisig is that you can lose some devices/backups and still recover your funds as long as you have enough to meet the threshold.

For a 2-of-3 setup, you could lose one device and its backup completely and still access your bitcoin with the remaining two devices.

Frostsnap uses the FROST Backup Format, a specialized backup scheme with built-in security features like polynomial checksums and fingerprint grinding.

See /recovery for recovery instructions and Backup & Recovery docs for more details.

To restore knowledge of your wallet onto a new phone or laptop visit a threshold number of devices.

Backups can be loaded into blank devices during this process.

See /recovery for more.

Frostsnap does not have a device PIN that unlocks a secure element. This was a specific design choice: PINs act as an additional piece of information you have to remember and they complicate inheritance.

With Frostsnap the devices themselves are the pieces of information you need to have access to (or their backups), in a forgiving threshold of your choosing.

Device secrets are encrypted with a decryption key being secured by your phone's secure element.

In order to know about the wallet or begin signing requests a phone must have visited a threshold number of devices, learning the decryption key.

Frostsnap's security model is strongest in a greographically distributed threshold multisignature protected behind multiple devices. With a simple 2-of-3:

• You need any 2 devices to sign transactions
• Losing 1 device doesn't compromise your funds
• An attacker needs to compromise 2 separate locations to steal your bitcoin

This provides both security (against theft) and redundancy (against loss). You can choose different thresholds like 3-of-5 for even more flexibility.

The Frostsnap app supports:

• Android
• Linux
• Windows
• MacOS

All software is free and open-source.