zigner

air-gapped zcash signing for android

spending keys stay on an offline phone. zcli talks to zigner through QR codes — no wifi, no bluetooth, no USB.

setup

# on zigner: generate wallet, display FVK QR
# on your machine:
zcli import-fvk --cam                     # scan the viewing key QR
zcli sync --wallet zigner                 # sync watch-only wallet
zcli balance --wallet zigner              # check balance

send

zcli send 1.0 u1... --wallet zigner --cam # build unsigned tx, show QR
# zigner scans it, signs offline, displays signed QR
# zcli scans signed QR back, broadcasts to network

the flow

zcli x zignerair-gapped

zigner (offline) zcli (online) ┌──────────────┐ ┌──────────────┐ │ generate keys │ FVK QR │ import-fvk │ │ hold spend key│ ──────────────▸ │ watch-only │ └──────────────┘ │ sync & build │ ┌──────────────┐ unsigned tx │ │ │ verify & sign │ ◂────────────── │ send --cam │ │ display QR │ ──────────────▸ │ broadcast │ └──────────────┘ signed tx └──────────────┘

keys never leave the deviceQR codes only