delvingbitcoin

Unspendable keys in descriptors

Unspendable keys in descriptors

Original Postby RandyMcMillan

Posted on: December 19, 2023 20:05 UTC

In the realm of cryptocurrency security and privacy, a technique is discussed that involves the use of an exclusive or (XOR) operation to enhance the complexity of analyzing extended public keys (xpubs).

By applying an additional XOR to the original xpub with another component, such as a BIP85-derived xpub, the process becomes significantly more difficult for external parties to scrutinize. This method can be implemented in a way that remains user-friendly, allowing wallet users to select an index to generate the BIP85 xpub. The implementation ensures that the operation remains recognizable by wallets, suggesting that it could maintain compatibility with existing wallet software while providing an extra layer of security through obfuscation.

This approach hinges on the premise that by introducing an element of unpredictability in the form of an XOR operation with a secondary xpub, the resultant data would require substantial effort to decode without the proper context or keys. The BIP85 standard is proposed as a source for this secondary xpub, which can be derived from a master seed based on a user-specified index. This would theoretically enable users to retain control over their keys and add a customizable layer of protection against unauthorized analysis of their public key data. It is implied that the integration of such a mechanism would not hinder the functionality of wallets, indicating that while the security aspect is bolstered, the ease of use and accessibility are preserved.