To scan for cash acquired to Bobs silent cost deal with, he wants to make use of his b_scan personal key for the reason that shared secret is calculated by the sender utilizing a*B_scan.
This query will not be about whether or not host wallets / companion apps for {hardware} wallets will make the most of scanning servers or some other strategy to implement scanning however moderately how they may take care of the personal key b_scan being required to be “on-line”.
- {hardware} wallets usually don’t assist exporting personal keys (and shouldn’t imo.)
- BIP-352 says that wallets MAY use BIP32 derivation paths however this may not be doable for {hardware} wallets that do not export personal keys.
How may doable implementations appear like? The host pockets / scanning server may simply compute all A (sender’s public key a1 + a2 + ... + an for n inputs) after which {hardware} wallets may have an API to calculate the shared secret given the A?
Recovering the pockets stability from a sure block peak (the block peak that the {hardware} pockets rolled out silent cost obtain for instance) could be plenty of work, and for all subsequent receives the {hardware} pockets additionally needs to be related.
Does anybody have an concept how {hardware} wallets may probably take care of this with out destroying UX / including complexity to the {hardware} pockets firmware?
