jade: support BIP388 policy signing
What the developer wrote
Authored by Sjors Provoost
jade: support BIP388 policy signing
Sign with the existing PSBT flow after registerdescriptor has stored the
policy on the device.
What changed, and why it matters
This change removes an error that previously blocked Bitcoin signing for a specific type of wallet policy (BIP388) on the Blockstream Jade hardware wallet. The device now supports these policies, so the software no longer needs to reject them. There is no obvious security bug being fixed; it appears to be a feature-enablement patch.
No immediate security action required. Review the Jade firmware's BIP388 implementation and register_descriptor/sign_tx interaction for correctness, but the commit itself does not indicate a security fix.
Security signals we found
Removal of an explicit unsupported-action error
No new cryptographic operations introduced
No input validation changes observed
No memory-safety or parsing changes observed
Evidence from the diff
In hwilib/devices/jade.py, the sign_tx method previously raised UnavailableActionError when registered_descriptors was present, because the Jade implementation did not support BIP388 policy signing. The patch removes that guard and adds a comment explaining that the descriptors are unused in sign_tx because they were already stored on the device via register_descriptor. The actual signing continues through the existing PSBT flow. This is a compatibility/feature update rather than a vulnerability remediation.
Changed components
hwilib/devices/jade.pyBlockstream Jade device integrationBIP388 descriptor policy signingInspect captured patch +1 / −2
### hwilib/devices/jade.py
@@ -383,8 +383,7 @@ def sign_tx(
"""
Sign a transaction with the Blockstream Jade.
"""
- if registered_descriptors:
- raise UnavailableActionError("The Jade does not support BIP388 policy signing")
+ # registered_descriptors are intentionally unused because the descriptors were stored by register_descriptor.
# Old firmware does not have native PSBT handling - use legacy method
if self.PSBT_SUPPORTED_FW_VERSION > self.fw_version.finalize_version():
return self.legacy_sign_tx(psbt)Why this scored 22/100
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