Expaining Bitcoin. Sign MULTISIG input

In this article, you will find details on how MULTISIG bare output works in Bitcoin network transactions. We will also describe the algorithm for signing this output option in the transaction input in detail. The following describes how to sign bare input MULTISIG with Python.

Bare MULTISIG output scenario implies the need for several keys in the transaction authorization process, depending on the number of signatures specified in the number of public keys available.

Creating a spending transaction from a given output option is required to access the unlock script for the output. The signature scenario includes a specific number of signatures, serialized as it matches each public key in the MULTISIG scenario.

Verification of a signed transaction input (an output of another transaction that has not been spent) is done by running the signature script, followed by the MULTISIG script.

How to execute the scenario 2 of 3 MULTISIG scenarios?

Execution done. If the signatures were valid on the stack at 01, the value is True and the transaction input is validated.

Bitcoin test network signs bare MULTISIG 2/3 point-by-point:

We have 0.64 tBTC in our hands, which are blocked on a bare MULTISIG input. We provide 3 public keys, each of which corresponds to an address:

We need transfer to mwJMtn5hW54pJC748EExvhRm6FRVmUZXQt.

Phase 1: Creation of an unsigned transaction with the empty script of a signature

Phase 2: We need a hash of the signature from this transaction (for this we will refer to the SIGHASH_ALL type)

Phase 3: Sign sighash with private keys

Phase 4: Inserting a signature in the transaction signing scenario with the order in which the public keys were placed in the MULTISIG scenario. Each signature must be accompanied by a byte of a sighash type

Phase 5: Start broadcasting a transaction to the network

7193e8e9894069253b52ebcdc74caf8eed5d93c00022dcf23fa096b27180fe21

Check out an example on the bitcoin Python library pybtc: