Multi-Vendor Multisig Using HW wallets from different manufacturers for the same multisig. Defense against single-vendor compromise (firmware bug, supply chain). Why multi-vendor If all 3 keys are on Ledger devices and Ledger has a critical bug: - All 3 keys potentially compromised. - 2-of-3 = full theft. Multi-vendor 2-of-3 (e.g., Trezor + Coldcard + Ledger): - One vendor's vulnerability doesn't compromise majority. - Need 2 simultaneous vulnerabilities + access. - Substantially harder to attack. Trade-offs - Multi-vendor signing UX harder : each vendor has different flows. - Coordinator com…