FROST for shielded ZEC, in the Ironwood pool.
How OpenPGP Wallet will remove the weak spot of a wallet that signs on a single device: the key that authorizes spending is shared between your computer, your phone and an encrypted offline backup, and is never rebuilt, not even when signing.
Two devices, one signature.
A key that is never whole
Created jointly (DKG) and signed by two out of three (FROST): no device ever holds all of it, neither at setup nor when signing.
The phone checks for itself
It decodes the transaction and recomputes what it signs: recipient, amount, fee and change. An infected computer can't make it sign something else.
No server
Pairing and signing over encrypted QR codes between your two devices: no third party, no server in between.
Lose a device, lose nothing
The third share, encrypted and kept offline, stands in for the missing device to move the funds to a new account.
Built on Zcash standards
ZIP 312 (FROST for spend authorization), ZIP 374 (partially created transactions) and the Zcash Foundation's FROST libraries. The signing messages and backups become an open specification any wallet can use.
A six-phase plan
From moving to the Ironwood pool to the independent audit, with real tests on mainnet along the way and the signer app for Android, then iPhone.
Where we stand
Nothing described here is implemented yet, and nothing has been reviewed by an independent auditor. This document sets out the design so it can be discussed in public.