2

I'm trying to write a BIP11-compliant C# client that creates a 2 of 2 or 2 of 3 transaction.

I'm also trying to understand if a 3 of 3 transaction is supported as well.

This example says they are creating a PS2H address, but I'm unsure of exactly what script is being signed, and the meaning of the parameters "2" in addmultisigaddress, and what happens when addmultisigaddress is called.

I have researched the BIP, the RPC documentation, and the forums. I'm getting confused where if and when the P2SH is needed.

Improve this question
2

I think the reason you might be getting confused is that there are really two types of multisig, raw multisig and P2SH (pay-to-script-hash) multisig. P2SH multisig is basically just hashing the actual scriptPubKey desired and putting the scriptPubKey in the scriptSig. This stack exchange questions explains them in more detail: What are the limits of m and n in m-of-n multisig addresses?.

I'm also trying to understand if a 3 of 3 transaction is supported as well.

Yes, you can do m-of-3 multisig transactions with both raw multisig and P2SH multisig.

the meaning of the parameters "2" in addmultisigaddress

The number provided is the m in the m-of-n. So if you want a 1-of-2, you do:

addmultisigaddress 1 '["1xy..", "1Jm..."]'

The BIP11 (accepted) proposal you mentioned just made raw multisig a standard type of transaction that is recognized and forwarded on by standard clients. BIP16 (https://github.com/bitcoin/bips/blob/master/bip-0016.mediawiki) proposes the P2SH addresses, which allow for much shorter scriptPubKeys and support more types of multisig (e.g. 5-of-9, which you can't easily do with raw multisig because m-of-n multisigs with n > 3 are considered non-standard, as shown in the link in the first paragraph).

Improve this answer
5
  • You have m and n mixed up. BIP11 uses m-of-n, where m is the minimum number of signatures and n is the number of keys. (Or at least that's how I remember it.)
    – David A. Harding
    Dec 15 '14 at 11:09
  • @DavidA.Harding, I update the post to use the standard notation.
    – morsecoder
    Dec 15 '14 at 14:24
  • @NickODell, which part do you think needs a clarification? I linked to this, which explains the size limits.
    – morsecoder
    Jan 14 '15 at 15:57
  • 1
    @StephenM347 (e.g. 5-of-9, which you can't do with raw multisig because it would make the scriptPubKey too large). I think that everything up to and including 20-of-20 multisig is valid. For example: blockchain.info/tx-index/49797406/0
    – Nick ODell
    Jan 14 '15 at 16:06
  • @NickODell Gotcha, I'll clarify that it's an issue of standardness rather than validity.
    – morsecoder
    Jan 14 '15 at 16:16

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.