FROST — OpenPGP Wallet

How it works FROST

FROST by the Zcash Foundation

Coming soon

01 The idea

After the backup, split the signature.

OpenPGP Wallet already splits your backup into three pieces, any two of which are enough. FROST takes the same logic to the most sensitive moment: signing a send. Several devices each sign their share, and the whole key is never rebuilt.

Today

Backup3 pieces, any 2 are enough

SignatureOn the computer, the key is rebuilt for a brief moment

Malware on the computerCould, in theory, catch the key at that moment

With FROST

Backup3 pieces, any 2 are enough

SignatureComputer + phone, each its own share: the key never exists whole

Malware on the computerCan't send anything on its own: it would also need the phone

02 Why

A Ledger's protection, with the phone you already own.

The one limit of a software wallet is a computer that's already infected. Hardware wallets solve it with a separate device and its own screen. FROST offers the same guarantee without buying anything: your phone becomes the second device and the trusted screen.

The phone shows the real recipient and the real amount, even if the computer lies.
You approve at a glance (Face ID or fingerprint): nothing more to do than today.
Phone lost or broken? The backup share, kept safe, takes over: any two out of three are always enough.

OpenPGP Wallet

Signing request

from your computer

0.5 ZECto u1qh…7x4e

NetworkShielded Zcash

Recipientu1qh…7x4e

Fee0.0001 ZEC

✓ Your computer has already signed its share

Approve with Face ID

Decline

03 How it will work

One setup, instant pairing, and native verification every time.

Pair

Just once: the computer shows a QR code, the phone scans it. The two devices create their shares together, then talk over an end-to-end encrypted channel.

Request

You prepare a send on the computer, just like today. It signs its share and sends the request to the phone.

Approve

The phone shows the send, you approve it at a glance, it signs its share. The two shares form an ordinary signature, accepted by the network.

04 Solid foundations

No homemade cryptography.

Joint signing is no place to improvise. The project builds on the most serious work available.

A public standard

FROST (Flexible Round-Optimized Schnorr Threshold) is standardized by the IETF as RFC 9591.

The Zcash Foundation's implementation

Its open-source Rust libraries, which we'll use as is, checked against the official test vectors.

Already in the Zcash ecosystem

The app already uses Zcash's official library (librustzcash) for transparent and shielded (Orchard) Zcash.

First networks targeted

Shielded Zcash, Solana, NEAR, Stellar and Bitcoin (Taproot addresses): all use Schnorr-type signatures, the kind FROST produces.

What FROST doesn't cover

Ethereum and compatible networks, Tron, XRP and Dogecoin sign differently (ECDSA): they need another, heavier family of protocols, considered later.

Without touching what works

FROST will be developed separately, in an isolated module: the current wallet and its backup will stay as they are throughout the research.

05 Where we stand

Design settled. Development ahead.

✓Design: devices, covered networks and pairing channel chosen

1Isolated research module, with the phone simulated by a second program, checked against the official vectors

2QR-code pairing and an end-to-end encrypted channel between the computer and the phone

3Mobile app: show the request, approve at a glance

4Independent security audit, before any use with real funds

Read the white paper Discover OpenPGP Wallet Wallet project status