Resolve Multi Signature ScriptSig

Question

How does the ScriptSig of a Multi Signature transaction resolve to "who" signed the transaction. I followed the Multi Signature example and I understand that the two second and third signature represent "who" signed the transaction but they don't seem to resolve to the public keys used to create the multi signature address. 

Here's the asm output from the mulit signature example I ran: 

Thanks.

0 3045022100a67e843b0fcd4dc97124b12074650b8dd0d8dcd136b9c889f40032a87f2b44f10220329ecd32d1ef47fdcde52d84bc98c63d45ec618c26f13a057f10a133a1cffd0f01 3045022100cf7e027a597d090ffec9f015ae06c6dc9d35e41b3906beb26610e50e7720a4b402205e7d027a52e52e095f8c864400734cf169238746fbb7ddac85b628a9d00610ca01 5221030f46d5c9d79ec59da5a4936cb89ba1f520519e94179cd7204cfa47e2bb9d7d7f2103b92167eaa572862e57e2874ad7bce38bbd8987b0c763cdd847219b1870dbb8e152ae

Answer 1

The answer to this is quite lengthy and involved, so the best thing is to read a detailed post about how multisigs work in bitcoin, since MultiChain follows exactly the same scheme:

http://www.soroushjp.com/2014/12/20/bitcoin-multisig-the-hard-way-understanding-raw-multisignature-bitcoin-transactions/

Comments

Yeah, that is lengthy and involved. Thanks for the link. Thinking that it might be easier to use appendrawdata and add an identifier after it's been signed. Are there any gotchas to using this method?

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This approach can also work, but you should add the metadata *before* anyone signs the transaction, so that each signing party can verify that they are listed in the metadata before adding their signature. For the subsequent reader, if the number of items in the metadata matches the number of signatures, and each person signing checked they are listed, you'll be able to rely on the metadata.