Code:
[version:1=0x2a] [options:1] [scan_pubkey:33] [N:1] [spend_pubkey_1:33] ...
[spend_pubkey_N:33] [number_sigs:1] [prefix_length:1] [prefix:prefix_length/8, round up]
options bitfield = 0 or 1 (reuse scan_pubkey for spends)
[spend_pubkey_N:33] [number_sigs:1] [prefix_length:1] [prefix:prefix_length/8, round up]
options bitfield = 0 or 1 (reuse scan_pubkey for spends)
It seems to me that the options bitfield above is redundant. If options = 1 you are not using the spend_pubkey:s so they can be omitted in order to shorten your address. If options = 0 you need the spend_pubkey:s since you don't want to reuse the scan_pubkey for spends. It seems to me that instead of having the options bitfield you can just look at if N = 0 or not. Or is it more like this bitfield is reserved for other options that might be introduced in the future?
/C