"Prepared output should be pay-to-pubkeyhash" when attempting a raw exchange with a multisig

Question

Should it be possible to have an atomic exchange between a regular address and a multisig? I keep encountering errors saying I need a pay-to-pubkeyhash. Example steps I'm doing below:

I have a multisig address that has signatories from both of my nodes. The multisig address is `381VVXe7NaeimsqQR3p3tAvVNd388dEcYs `. This address is fine, I'm able to do normal raw transactions with it.

I issue a custom asset USD to one of my addresses:

`issue 1BUArAafjtLBhWZru1sM6ZbQJ2rbXDn3RR USD 2000 0.01`

I lock some amount of USD:

`preparelockunspentfrom  1BUArAafjtLBhWZru1sM6ZbQJ2rbXDn3RR '{"USD": 100}'`

Txid b5fb8e75814ea5602e960700f90d5b9127cb32eb68441ee6437b63a759025786

I also prepare some amount of native currency on the multisig:

`createrawsendfrom 381VVXe7NaeimsqQR3p3tAvVNd388dEcYs '{"381VVXe7NaeimsqQR3p3tAvVNd388dEcYs": {"":9900}}' '[]' lock,sign`

I sign it on the 2nd node and send the transaction. This is fine. Txid 54e228a37769850f1ada2aa15a85a7497a915600d661462f1e526b9a99fbd127

I create a raw exchange using the 100 USD reserved above for 9900 native currency:

createrawexchange" b5fb8e75814ea5602e960700f90d5b9127cb32eb68441ee6437b63a759025786 0 '{"":9900}'

I call appendrawexchange, confirming I accept 100 USD in exchange:

`appendrawexchange <raw-exchange-from-above> 54e228a37769850f1ada2aa15a85a7497a915600d661462f1e526b9a99fbd127 0 '{"USD": 100}'`

At this point I get an error:

error code: -5
error message:
Prepared output should be pay-to-pubkeyhash

The error occurs no matter on which node I try to execute the above command.

I'm unsure what this error message means. Have I missed a step? Or is this simply not allowed?

Thank you

Answer 1

I'm afraid you cannot use the high-level exchange APIs for multisig addresses, because part of creating or appending to an exchange is signing the transaction, and the full signature cannot be applied for a multisig if one of its required private keys is on another node.

Your solution here instead of using appendrawexchange is to use appendrawtransaction + signrawtransaction. There is documentation on this page for a case with a regular address that uses external private keys, rather than a multisig, but the principle is the same:

https://www.multichain.com/developers/atomic-exchange-transactions/

Search on that page for appendrawtransaction which is the stage where you see the problem.

Comments

If the multisig address prepares the transaction, how does the following step change:

 signrawtransaction [paste-hex-blob] '[]' '["V..."]' SINGLE|ANYONECANPAY

If I try to add the SINGLE|ANYONECANPAY parameter to any of the multisig signing stages, the hex output is the same as the input (decoding shows that no signature was added)

If it matters, I am not passing the private keys in the 3rd parameter; the multisig signatories have their private keys stored in the nodes:

signrawtransaction <hex-blob> '[]' '[]' SINGLE|ANYONECANPAY

If I remove the SINGLE|ANYONECANPAY parameter, the raw transaction can be signed and completed (IDK what happens if I send it)

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I'll re-post my followup as a separate question instead.