sign a message with multisig

[FabioCarpi]

there a way to sig a message with multisig address?
if not, there a nice idea...

[cbeast]

That's what multisigs are. They are created by signing with public keys.

[amaclin]

there a way to sig a message with multisig address?
if not, there a nice idea...

Why not to sign one message with two (three, four...) keys?
Note: we do not sign a message with address! We sign it with private key

[cbeast]

there a way to sig a message with multisig address?
if not, there a nice idea...

Why not to sign one message with two (three, four...) keys?
Note: we do not sign a message with address! We sign it with private key

IIRC a public key (not public address) is used to make multisig in the same way an address is signed by creating a public key.
In other words a bitcoin public key can exist without being seen by the blockchain, while a multisig address doesn't exist until it's been seen by the blockchain.

[amaclin]

...while a multisig address doesn't exist until it's been seen by the blockchain.

And how would you fund non-existing in blockchain multisig address? 

[DannyHamilton]

there a way to sig a message with multisig address?
if not, there a nice idea...

No, you don't sign with addresses. You sign with private keys.

It is possible to use multiple private keys to provide multiple signatures on a message.  This is what a multisig address requires.

That's what multisigs are. They are created by signing with public keys.

No, you don't sign with public keys. You sign with private keys.

Multisig addresses are created by creating an output script that requires multiple signatures to be spent, and then hashing that script.  The resulting hash is used to generate a P2SH address.

IIRC a public key (not public address) is used to make multisig in the same way an address is signed by creating a public key.

What?

Version 1 addresses aren't typically signed. Version 1 addresses are a Pay-to-PubKeyHash output script with a version number and a checksum. The resulting bytes are then converted to base58.

In other words a bitcoin public key can exist without being seen by the blockchain, while a multisig address doesn't exist until it's been seen by the blockchain.

A multisig address does not need to be seen by the blockchain in order to "exist". Why do you think that?

[cbeast]

there a way to sig a message with multisig address?
if not, there a nice idea...

No, you don't sign with addresses. You sign with private keys.

It is possible to use multiple private keys to provide multiple signatures on a message.  This is what a multisig address requires.

That's what multisigs are. They are created by signing with public keys.

No, you don't sign with public keys. You sign with private keys.

Multisig addresses are created by creating an output script that requires multiple signatures to be spent, and then hashing that script.  The resulting hash is used to generate a P2SH address.

IIRC a public key (not public address) is used to make multisig in the same way an address is signed by creating a public key.

What?

Version 1 addresses aren't typically signed. Version 1 addresses are a Pay-to-PubKeyHash output script with a version number and a checksum. The resulting bytes are then converted to base58.

In other words a bitcoin public key can exist without being seen by the blockchain, while a multisig address doesn't exist until it's been seen by the blockchain.

A multisig address does not need to be seen by the blockchain in order to "exist". Why do you think that?

I see, so the output script is created by one person. I thought anonymous people could participate in creating a multisig transaction through the blockchain, but apparently you need an off chain communication method to arrange the transaction itself.

[DannyHamilton]

I see, so the output script is created by one person . . . apparently you need an off chain communication method to arrange the transaction itself.

Correct.

I thought anonymous people could participate in creating a multisig transaction through the blockchain

The blockchain is nothing more than a chain of blocks.  A block is nothing more than a header with some basic information about the block followed by list of transactions.

There is no method "in the blockchain" for creating a multisig address (or any other type of address).