SettingsQRs are a way to encode the settings options for the SeedSigner into a QR code. This allows users to easily load the settings into their SeedSigner without having to manually enter them one-by-one.
Because SettingsQRs only store settings options, they are safe to share publicly. They do not contain any sensitive information like seeds or xpubs.
Some basic use cases:
- An instructor has a class of bitcoin beginners and has them start by scanning a SettingsQR that disables all advanced settings. The next class is an advanced group that uses the same devices, so they begin by scanning a different SettingsQR that's customized for their session's more advanced topic.
- Customer support for a company offering collaborative custody begins each support call by having the customer load the company's preferred multisig-only settings.
The data in a SettingsQR is just a series of key=value pairs, separated by whitespace (spaces or line breaks).
Each SettingsQR begins with:
settings::v1
This signals to SeedSigner that this is a SettingsQR to differentiate it from the variety of other QR codes that the SeedSigner can parse.
(there is only one version of the SettingsQR format at this time)
The key=value pairs then follow:
settings::v1
persistent=D
coords=bw,nun,spa,spd
denom=thr
network=M
...
The SettingsQR Generator uses spaces instead of line breaks, but the end result is the same.
settings::v1 persistent=D coords=bw,nun,spa,spd denom=thr network=M ...
The key names are taken from the SeedSigner SettingsDefinition, where each setting is described in a SettingsEntry. SettingsQRs should use the abbreviated_name (e.g. "coords") if it exists in the SettingsEntry, otherwise use the attr_name (e.g. "coordinators").
The value options are pulled from the SettingsEntry's selection_options list. Settings that allow for multiple selections should be comma-separated in the SettingsQR value (e.g. "bw,nun,spa,spd" for the "coords" setting).
A SettingsQR may specify a name for itself as its first key=value pair:
settings::v1
name=Keith's_basic_settings
persistent=D
coords=bw,nun,spa,spd
denom=thr
network=M
...
The name cannot include any whitespace or the = character. SeedSigner will display the name on the SettingsQR screen when the user scans the SettingsQR to help the user identify which settings they just loaded.
SeedSigner will replace underscores ("_") with spaces when displaying the name.
If a key is missing from the SettingsQR, SeedSigner will use the default value for that SettingsEntry.
The only exception to this is for hidden settings (e.g. qr_brightness); if a value is already specified in the user's current settings, SeedSigner will preserve that value.
SeedSigner will ignore any key entries that don't correspond to a SettingsEntry.
SeedSigner will raise an Exception if it encounters a value that is not in the selection_options list for that SettingsEntry.
SettingsQR configured for limited options for a beginner:
SettingsQR configured for an advanced multisig user:
