Add P2SH-Multisig support #12

bjarnemagnussen · 2017-10-13T19:25:58Z

Adds support for Pay-To-Script-Hash (P2SH) multi-signature contracts.

The multi-signature scheme is compatible with Bitcoin Core, and therefore partially-signed transactions can be co-signed between both implementations.

New classes:

MultiSig and MultiSigTestnet.

Example usage:

from bit import *

# Creating three private keys:
key1 = PrivateKeyTestnet("cNZYKrewErp2wG9LXiAU4H6dzgtyYsSm78tSU14QST9Hu57CMRaJ")
key2 = PrivateKeyTestnet("cMgHThJYoUYc19UjMWn1xabRJLh3PCKyKfiTM1ssV2ZPe7V6eaBL")
key3 = PrivateKeyTestnet("cR1C9ZB7qoVktmQDQsUP8KcTM37G1PYN3oR2B6ua27EycGDVN6fE")

# Making a list containing the public keys in hex:
key1p = key1.pub_to_hex()
key2p = key2.pub_to_hex()
key3p = key3.pub_to_hex()
plist = [key1p, key2p, key3p]

# Creating a P2SH multi-signature contract instance with key1 requiring two signatures from the total of three keys:
multi = MultiSigTestnet(key1, plist, 2)

# Showing the multi-signature address to send (testnet) bitcoins to:
multi.address
# 2MvkZtmW1w7hBPMSjQmEhHzrtcgiQGEBrtD

# Create and partially-sign a new transaction spending from the multi-signature contract:
tx = multi.create_transaction([], fee=21, leftover='mpDJqjKMyQaFjEMwYHKJBP3mM4rM2ejJdk')

# Create another instance of the multi-signature contract with key2:
multi2 = MultiSigTestnet(key2, plist, 2)

# Fully sign the spending transaction using our second instance of the multi-signature contract:
tx_signed = multi2.sign_transaction(tx)

This is only thought of as a first start to implement P2SH and therefore bugs are still expected and more rigorous testing and optimization may be necessary.

Adds support for Pay-To-Script-Hash (P2SH) multi-signature contracts. The multi-signature scheme is compatible with Bitcoin Core, and therefore partially-signed transactions can be co-signed between both implementations. New classes: MultiSig and MultiSigTestnet. Example usage: from bit import * key1 = PrivateKeyTestnet("cNZYKrewErp2wG9LXiAU4H6dzgtyYsSm78tSU14QST9Hu57CMRaJ") key2 = PrivateKeyTestnet("cMgHThJYoUYc19UjMWn1xabRJLh3PCKyKfiTM1ssV2ZPe7V6eaBL") key3 = PrivateKeyTestnet("cR1C9ZB7qoVktmQDQsUP8KcTM37G1PYN3oR2B6ua27EycGDVN6fE") key1p = key1.pub_to_hex() key2p = key2.pub_to_hex() key3p = key3.pub_to_hex() plist = [key1p, key2p, key3p] from the total of three keys: multi = MultiSigTestnet(key1, plist, 2) multi.address tx = multi.create_transaction([], fee=21, leftover='mpDJqjKMyQaFjEMwYHKJBP3mM4rM2ejJdk', unspents=unspent) multi2 = MultiSigTestnet(key2, plist, 2) tx_signed = multi2.sign_transaction(tx) spending from the multi-signature contract. This is only thought of as a first start to implement P2SH and therefore bugs are still expected and more rigorous testing and optimization may be necessary.

ofek · 2017-10-14T01:37:13Z

You have done a lot of work here, thanks! I'll look soon.

Update to latest version 0.4.1 of bit

Update multisig branch to version 0.4.1 of Bit

bjarnemagnussen

There is a bug where string is compared with bytes when constructing outputs and checking the cases of the output-types (P2PKH/P2SH)

bjarnemagnussen · 2017-12-02T18:44:57Z

bit/transaction.py

-        # Real recipient
-        if amount:
+        # P2SH
+        if amount and (b58decode_check(dest)[0] == MAIN_SCRIPT_HASH or 


I produced a bug here. b58decode_check(dest)[0] casts to a string which is then compared to MAIN_SCRIPT_HASH which is bytes. This is serious, because outputs to P2SH will not be catched and instead be interpreted as P2PKH outputs...

bjarnemagnussen · 2017-12-02T18:45:38Z

bit/transaction.py

-        if amount:
+        # P2SH
+        if amount and (b58decode_check(dest)[0] == MAIN_SCRIPT_HASH or 
+                       b58decode_check(dest)[0] == TEST_SCRIPT_HASH):


Same problem as above.

ghost · 2017-12-17T02:47:40Z

In #23 I talked about throwing an exception for mainnet addresses that do not begin with a 1. Am I correct in understanding that there are no tests in place for that currently?

ofek · 2017-12-17T23:43:06Z

@teran-mckinney Yes, not yet.

We don't yet support pay2sh. Until #12 is ready, we should throw exceptions if given an address in an unexpected format.

dspechnikov · 2018-03-20T12:32:57Z

Any chance this will be finished anytime soon? I need to be able to send transactions to P2SH addresses.

bjarnemagnussen · 2018-04-08T12:51:53Z

@dspechnikov: I hope to be able to continue working on it. But you can maybe try to test this branch a little, because it actually does allow you to send to P2SH addresses, see here:
https://github.com/bjarnemagnussen/bit/blob/c17d730c8d84ffe4602bb53ca964db123794fc0e/bit/transaction.py#L247

I just highly recommend not to use it in production, as it has not yet been tested thoroughly.

impowski · 2018-06-12T02:49:33Z

@bjarnemagnussen Any progress on this one?

bjarnemagnussen · 2018-06-13T11:03:51Z

Just to make sure: the master branch of my fork (https://github.com/bjarnemagnussen/bit) already has the ability to make P2SH-Multisig and also supports sending to Segwit addresses (including bech32) and receiving to P2SH-nested Segwit addresses. I have been fixing a few bugs I found regarding the interoperability with Bitcoin Core, so that e.g. a partially signed transaction from either Bit or Bitcoin Core can now be exchanged and fully signed.

But since only I have been testing it, I am not confident in suggesting to use it in production. However, all the functionality is implemented and I did not encount any problems. So maybe just check it out with testnet coins or small amounts and let me know if there are any problems.

I have not yet written any documentation for the Segwit features. But you can see the segwit address by calling

key = PrivateKey()
key.sw_address

Bit will then by itself take care of creating/signing transactions using segwit inputs if there are any (make sure to call key.get_unspents() before creating/signing transactions, just as before). It is similar for Multig instances.

Some parts of the code are still a little cluttered and I want to clean it up a bit. Of course, that should not influence the operation of it.

impowski · 2018-06-13T16:40:43Z

@bjarnemagnussen could you please give me little guide how to use it with multisig?

bjarnemagnussen · 2018-06-13T17:02:43Z

@impowski: Have a look at my first message in this pull request. Let me know if you need some clarification on the example.

impowski · 2018-06-13T17:51:54Z

@bjarnemagnussen when I did sign_transaction my Python freezes, maybe it's me, need to check it.

impowski · 2018-06-14T01:22:09Z

@bjarnemagnussen Yeah, it doesn't work I guess, can you check it on your machine?

bjarnemagnussen · 2018-06-14T09:41:36Z

@impowski Can you show me how you initiate your keys and call the function so that I can check it?

impowski · 2018-06-14T11:48:30Z

@bjarnemagnussen

from bit import PrivateKeyTestnet, MultiSigTestnet

private_keys_hex = ['b4741e2e87c19256c81a0662480b75f15831c7017d28b4586882c52b89f91bcf', '3c212d5724a2a6bd5004c502a4be7ba55a1cf4a0923ffd1a9bb3cb6fd7201bed']

private_keys = [
    PrivateKeyTestnet.from_hex(private_keys_hex[0]),
    PrivateKeyTestnet.from_hex(private_keys_hex[1])
]

private_keys[0].instance

public_keys = [
    private_keys[0].pub_to_hex(),
    private_keys[1].pub_to_hex()
]

multisig = MultiSigTestnet(private_keys[0], public_keys, 2)
unspents = multisig.get_unspents()

tx = multisig.create_transaction([('2Mv7MJVHeqjyLVFUg7hc1oJoWedYySeGBsh', 100, 'usd')], unspents=unspents)

multisig2 = MultiSigTestnet(private_keys[1], public_keys, 2)

tx_signed = multisig2.sign_transaction(tx)

print(tx_signed)

impowski · 2018-06-14T12:03:31Z

@bjarnemagnussen And when I take for example partially signed transaction and signing it with second key myself I can't broadcast it to the network. Because for the first input witness script is different and I have a non-segwit address in the output.

bjarnemagnussen · 2018-06-14T14:46:52Z

@impowski Thanks for your feedback! I have found the bug and fixed it with a new commit to my master branch. The problem was in the way signatures from partially signed transactions were extracted, since coincidently the redeemscript was exactly of the same length as typically a signature is. It is on my todo-list to improve it further.

Furthermore, since you are using the segwit functionality you must make sure that also the instance multisig2 has the correct unspents initiated (e.g. by calling multisig2.get_unspents() before multisig2.sign_transaction()). This is because signatures in segwit are done for a string containing the amount it spends with the inputs. The amounts are provided from the unspents in multisig2.

impowski · 2018-06-14T15:00:36Z

@bjarnemagnussen It signs transaction right now, but can't broadcast it:
You can decode it on https://live.blockcypher.com/btc-testnet/decodetx/

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

The output address is different, input address is basically SegWit address and in the output it's just basic address and the witness script is kinda messy I guess.

bjarnemagnussen · 2018-06-14T15:41:34Z

@impowski I think this is unfortunately a problem with blockcypher using testnet.

Can you try to push the transaction on testnet using blockchain.info (https://testnet.blockchain.info/pushtx) or your own node and let me know if it worked?

Edit: Regarding the output address. For now it simply uses the original implemention to determine a return address, which therefore is the legacy address of the multisig. I will later at a later point make a check so that if it spends from at least one segwit input it returns to the segwit address.

impowski · 2018-06-14T15:53:41Z

@bjarnemagnussen How do you recommend sending it? Via NetworkAPI or smth different? Aaaaaaaaaaaand it works, we will use your fork in production until PR drops.

impowski · 2018-06-14T16:00:42Z

@bjarnemagnussen And the address is still different. If I write private_key.address I get this one 2N7tpkpBJPmv2BD37eTXDUJJzhpXEoyyNU9, if I write private_key.sw_address I get this one which I need 2N2qWuN9rpfw4DvPqjJ3SD1adNnmZdeM5NU. The problem is that an output gives me the first one. Here is the transaction https://chain.so/tx/BTCTEST/2c13d962de6c63253daf477214ea3207cfdab14b8844003e096f331052198b1a

impowski · 2018-06-14T16:05:02Z

@bjarnemagnussen I don't know what to do now with my faucet funds they've gone to the beyond world I guess 😨

bjarnemagnussen · 2018-06-14T16:11:39Z

@impowski It should work to use a direct call to NetworkAPI.broadcast_tx_testnet(tx_hex) which uses a call to BitPay or alternatively SmartBit to push the testnet transaction. But I haven't tested the NetworkAPI with testnet a lot.

In the future I will make the send-function allow to finally sign and then directly broadcast a transaction. But until now this is not possible.

I am not sure I understand your last question correctly. You can still spend the new testnet coins you received to the legacy multisig (2N7tpkpBJPmv2BD37eTXDUJJzhpXEoyyNU9). The multisig instance will always check both legacy and segwit unspents. You just have to make sure your multisig instance has access to the unspents (by running multisig.get_unspents() and then create and sign your transaction just as before).

You are very welcome to open an issue on my fork if you find any problems!

impowski · 2018-06-14T16:16:36Z

@bjarnemagnussen But why it sent on legacy address when I needed it on segwit address? That a kinda problem I guess. Oh I see...
I guess that's why:

unspents, outputs = sanitize_tx_data(
            unspents or self.unspents,
            outputs,
            fee or get_fee_cached(),
            leftover or self.address,
            combine=combine,
            message=message,
            compressed=self._pk.is_compressed(),
            version='test'
        )

bjarnemagnussen · 2018-06-14T16:22:31Z

@impowski You can always manually set the return address to the segwit-address like this multisig.create_transaction([('2Mv7MJVHeqjyLVFUg7hc1oJoWedYySeGBsh', 100, 'usd')], leftover=multisig.sw_address, unspents=unspents)

Edit: But this is getting a little off-topic for the multisig-implementation, so maybe open a new issue on my fork if there should be something else.

impowski · 2018-06-14T16:25:53Z

@bjarnemagnussen Oh thanks, totally forgot about that. We will use it in production some time and I'll let you know if anything new will get in the way. Big thanks for help and for that fix 💯

Make some better checks to validate signatures extracted from partially signed transactions.

impowski · 2018-07-04T17:51:56Z

Used this PR in production, everything seems fine so far. Can't wait till it be finally merged in master and published. Amazing work @bjarnemagnussen 🎉

7hacker · 2018-08-10T23:19:15Z

🎉 Works on mainnet! Moved some coins to a multisig wallet on Coinbase from a wallet generated by this library

ghost · 2018-08-14T04:18:04Z

@ofek, what do you think about merging this?

ofek · 2018-08-14T04:27:36Z

@teran-mckinney Go ahead 🙂

ghost · 2018-08-15T18:06:53Z

Here goes nothing... might need some cleanup but seems like it's time.

7hacker · 2018-08-15T18:12:43Z

woot! 👏 Thanks for your great work here!

Updates branch to current master including MultiSig

Bjarne Magnussen added 2 commits October 12, 2017 20:58

Seperates the signing procedure from the transaction creation function

ed0af3d

bjarnemagnussen added 3 commits November 2, 2017 17:33

Merge pull request #1 from ofek/master

322750a

Update to latest version 0.4.1 of bit

Merge pull request #3 from bjarnemagnussen/master

a81726e

Update multisig branch to version 0.4.1 of Bit

Removes bug that compared string with byte

c17d730

bjarnemagnussen commented Dec 3, 2017

View reviewed changes

ghost mentioned this pull request Dec 17, 2017

Pay to scripthash #23

Closed

ghost mentioned this pull request Dec 18, 2017

Closes #23 - Raise exception when using pay2sh addresses #24

Merged

ofek pushed a commit that referenced this pull request Jan 15, 2018

Closes #23 - Raise exception when using pay2sh addresses (#24)

89dcd0a

We don't yet support pay2sh. Until #12 is ready, we should throw exceptions if given an address in an unexpected format.

Bugfix when extracting signatures from partially signed tx

ff26461

Make some better checks to validate signatures extracted from partially signed transactions.

ghost merged commit 3a79a28 into ofek:master Aug 15, 2018

vden mentioned this pull request Aug 30, 2018

Allow sending to P2SH addresses #45

Closed

ghost pushed a commit that referenced this pull request Sep 13, 2018

Merge pull request #12 from ofek/master

3157771

Updates branch to current master including MultiSig

bjarnemagnussen deleted the multisig branch January 19, 2019 05:24

This pull request was closed.

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Add P2SH-Multisig support #12

Add P2SH-Multisig support #12

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Add P2SH-Multisig support #12

Add P2SH-Multisig support #12

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bjarnemagnussen commented Oct 13, 2017

Adds support for Pay-To-Script-Hash (P2SH) multi-signature contracts.

New classes:

Example usage:

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