New COLDCARD EDGE Release: Versions 5.3.3X (Mk4) and 1.2.3QX (Q)

What is EDGE?

new_edge is our newest long-lived branch that contains features that may not be ready for prime time, such as Taproot and Tapscript, BSMS and Miniscript.

Our standards for releasing new Edge versions are lower, so we can iterate faster and get these advancements out to other developers as soon as possible.

Now with latest Mk4/Q features from 5.3.3/1.2.3Q release. Contains all improvements already in master release.

Powerful New Feature: Provably unspendable ranged extended keys and unspend(...) descriptor fragment

Up to this point COLDCARD only allowed to use static bare xonly pubkeys as unspendable internal keys (number 3.,4. and 5. from here). With this new release two new recommended options were added (1. and 2. from here) that allows internal key to be properly ranged and encoded as normal extended key (or as unspend(...)). This offers better privacy to users that do not wish to reveal that internal key path is not spendable.


Properties of ranged unspendable extended keys and unspend(...):

  • unspendable keys are indistinguishable from a random key for an external observer
  • in a descriptor with the range operator, each change/address_index combination generates a different unspendable pubkey, and they are not relatable to each other (no fingerprinting)
  • the fact that a certain key is unspendable is easy to detect with full knowledge of the descriptor

More context:

Other New Features

  • New Feature: Address ownership for taproot, miniscript and tapscript wallets.
  • Enhancement: Miniscript and (BB)Qr codes. Allow import/export of miniscript via QR. Try here.

Bug Fixes

  • Bugfix: Constant AFC_BECH32M incorrectly set AFC_WRAPPED and AFC_BECH32.
  • Bugfix: Trying to set custom URL for NFC push transaction caused yikes
  • Bugfix: Fix yikes displaying BIP-85 WIF when both NFC and VDisk are OFF
  • Bugfix: Fix inability to export change addresses when both NFC and Vdisk id OFF
  • Bugfix: In BIP-39 words menu, show space character rather than Nokia-style placeholder which could be confused for an underscore.
  • Bugfix: Properly clear LCD screen after simple QR code is shown

Video Tutorials

We have a growing library of video tutorials on Youtube … and we’re still adding more!