Reclaiming of Multi-Sig Fees

[davestaxcp]

Many users who have used Counterparty functionality like MPMA sends, Large broadcasts and large description updates... especially on Legacy addresses have wanted to 'reclaim' some of those multi-sig fees.

Recently Dan Anderson (droplister) released a alpha early version of a desktop extension for the xcp.io block explorer and offered this as a service in his wallet:
https://github.com/XCP/extension/tree/main/dist

You can also check your addresses if there is recoverable BTC possible to 'reclaim' (though Dan said this page might be temporary):
https://api.xcp.io/scan

Sectioned this discussion as a general topic instead of a CIP (not sure if this is a protocol change or just something for wallet developers)

Basically it's just a push to wallet developers and infrastructure providers to offer this as a service (was extremely popular for older users to want this functionality)

[droplister]

I have developed such a feature, but a core part of it's functionality I did not open source as I'm trying to monetize my work on this issue.

That's not to discourage people from improving on this issue and supporting the feature.

The difficulty with reclaiming these fees have been:

• Indexing bare multi sig outputs. No standard API gives you a list of these outputs, you need to scan and build such a list.
• Determining which address and address type is associated with the pubkey. Is it the right, real address or just data.
• Given you've figured out the above, is it actually recoverable. Some aren't, but it's hard to tell in many cases.
• And is it a STAMP or not because you might not want to recover it, in that special case.

And the dataset is always changing, so in practice it's a lot of indexing and verification. I chose to do a lot of it upfront in bulk, but you could definitely do it real-time, ad hoc. But because of how Counterparty users re-use addresses you may have to scan thousands of transactions via API requests and you will hit rate limits doing so.