How to Spend From a Multisig Address

This example is a continuation of How to Create a Multisig Address.

Send 0.001 bitcoins (100000 satoshis) to the multisig address 3A6oGpJ5MzABAj9PofXKjcpTJCgYrdGBNJ using any Bitcoin wallet.

View the example transaction on blockchain.info.

Confirm Receipt of Bitcoin

Look up the balance of the multisig address.

$ bx fetch-balance 3A6oGpJ5MzABAj9PofXKjcpTJCgYrdGBNJ

balance
{
    address 3A6oGpJ5MzABAj9PofXKjcpTJCgYrdGBNJ
    confirmed 100000
    received 100000
    unspent 100000
}

Notice that balance.confirmed shows that the transaction has at least one confirmation.

Create a Transaction

Look up the preceding transaction by its hash.

$ bx fetch-tx f759759bc998ec96879e4ae8c1639e8a186e0d507401eb32e4479de64d340605

transaction
{
    hash f759759bc998ec96879e4ae8c1639e8a186e0d507401eb32e4479de64d340605
    inputs
    {
        input
        {
            address 1FLrh6Q1URcdSNKYCSnQwdpakpPPmwg7xd
            previous_output
            {
                hash 6098bb548c49dd9934650627f07f3bd62bf8f3cb4aab391edc0ea36fe82b1081
                index 0
            }
            script "[3045022100cf822811fb316a42844f8b30a5e1026ec8ab7df58e1b28a1a8cf2d6522f9390302204549cdcb6956bdfbea59698aea443281a208972fa02a6cb3f796aaa3191bff9601] [04f539b68ab0d5c0c75a78e81a86d76aafd83fa7978d55f347fb583a461af37b72babce7680b67e5760e6af74024e2526d8670d94158697b72f665a770f8fa58fe]"
            sequence 4294967295
        }
    }
    lock_time 0
    outputs
    {
        output
        {
            address 1KDCjpWXE2VbFotygTQ4T3jThz65YmfEq6
            script "dup hash160 [c7c10de3b95e020766d0c98d087a0cef2dfecbbe] equalverify checksig"
            value 3999880000
        }
        output
        {
            address 3A6oGpJ5MzABAj9PofXKjcpTJCgYrdGBNJ
            script "hash160 [5c406de4915e37a7e71c7ef9bff42fbf1404daa0] equal"
            value 100000
        }
    }
    version 1
}

The input for the new transaction will be transaction.outputs[1] (because it is the unspent output of the multisig address). This input is formatted as transaction hash:index, where the index is the zero-based position of this previous output in its transaction.

f759759bc998ec96879e4ae8c1639e8a186e0d507401eb32e4479de64d340605:1

The output for the new transaction is formatted as address:amount, where the amount is a number of satoshis. There are 100,000 satoshis available to spend, of which this transaction will spend 55% to Freenet.

1966U1pjj15tLxPXZ19U48c99EJDkdXeqb:55000

In this example the remainder will not be spent to any address. This will result in 45,000 satoshis being earned by miners as a transaction fee.

Construct the transaction from the inputs and outputs, in this case one of each.

$ bx tx-encode -i f759759bc998ec96879e4ae8c1639e8a186e0d507401eb32e4479de64d340605:1 -o 1966U1pjj15tLxPXZ19U48c99EJDkdXeqb:45000

01000000010506344de69d47e432eb0174500d6e188a9e63c1e84a9e8796ec98c99b7559f70100000000ffffffff01c8af0000000000001976a91458b7a60f11a904feef35a639b6048de8dd4d9f1c88ac00000000

Inspect the transaction visually.

$ bx tx-decode 01000000010506344de69d47e432eb0174500d6e188a9e63c1e84a9e8796ec98c99b7559f70100000000ffffffff01c8af0000000000001976a91458b7a60f11a904feef35a639b6048de8dd4d9f1c88ac00000000

transaction
{
    hash 028678bd699174ca9c305b81fe78d69c28cb2483ead9f492cd25bfac787326a4
    inputs
    {
        input
        {
            previous_output
            {
                hash f759759bc998ec96879e4ae8c1639e8a186e0d507401eb32e4479de64d340605
                index 1
            }
            script ""
            sequence 4294967295
        }
    }
    lock_time 0
    outputs
    {
        output
        {
            address 1966U1pjj15tLxPXZ19U48c99EJDkdXeqb
            script "dup hash160 [58b7a60f11a904feef35a639b6048de8dd4d9f1c] equalverify checksig"
            value 45000
        }
    }
    version 1
}

Notice that transactions.inputs[0].script is empty. This means that the input has not been endorsed.

Create the first endorsement for the first input 028678bd...:0 of the new transaction, using the first private key, the multisig script and the new transaction.

$ bx input-sign 9d695afea1c3ab99e11248e4b74e698332b11f5c5c051e6e80da61aa19ae7c89 "2 [02b66fcb1064d827094685264aaa90d0126861688932eafbd1d1a4ba149de3308b] [025cab5e31095551582630f168280a38eb3a62b0b3e230b20f8807fc5463ccca3c] [021098babedb3408e9ac2984adcf2a8e4c48e56a785065893f76d0fa0ff507f010] 3 checkmultisig" 01000000010506344de69d47e432eb0174500d6e188a9e63c1e84a9e8796ec98c99b7559f70100000000ffffffff01c8af0000000000001976a91458b7a60f11a904feef35a639b6048de8dd4d9f1c88ac00000000

30440220695a28c42daa23c13e192e36a20d03a2a79994e0fe1c3c6b612d0ae23743064602200ca19003e7c1ce0cecb0bbfba9a825fc3b83cf54e4c3261cd15f080d24a8a5b901

Create the second endorsement for the first input 028678bd...:0 of the new transaction, using the second private key, the multisig script and the new transaction.

$ bx input-sign 68ebab45a918444d7e088c49bda76d7df89b9ea6ba5ddeb1aab5945391828b83 "2 [02b66fcb1064d827094685264aaa90d0126861688932eafbd1d1a4ba149de3308b] [025cab5e31095551582630f168280a38eb3a62b0b3e230b20f8807fc5463ccca3c] [021098babedb3408e9ac2984adcf2a8e4c48e56a785065893f76d0fa0ff507f010] 3 checkmultisig" 01000000010506344de69d47e432eb0174500d6e188a9e63c1e84a9e8796ec98c99b7559f70100000000ffffffff01c8af0000000000001976a91458b7a60f11a904feef35a639b6048de8dd4d9f1c88ac00000000

3045022100aa9096ce71995c24545694f20ab0482099a98c99b799c706c333c521e51db66002206578f023fa46f4a863a6fa7f18b95eebd1a91fcdf6ce714e8795d902bd6b682b01

Encode the multisig script, for embedding in the endorsement script.

$ bx script-encode "2 [02b66fcb1064d827094685264aaa90d0126861688932eafbd1d1a4ba149de3308b] [025cab5e31095551582630f168280a38eb3a62b0b3e230b20f8807fc5463ccca3c] [021098babedb3408e9ac2984adcf2a8e4c48e56a785065893f76d0fa0ff507f010] 3 checkmultisig"

522102b66fcb1064d827094685264aaa90d0126861688932eafbd1d1a4ba149de3308b21025cab5e31095551582630f168280a38eb3a62b0b3e230b20f8807fc5463ccca3c21021098babedb3408e9ac2984adcf2a8e4c48e56a785065893f76d0fa0ff507f01053ae

Create an endorsement script using the two endorsements and the encoded multisig script, and assign it to the first input of the transaction.

The zero opcode is necessary due to an off-by-one error in the reference client.

$ bx input-set "zero [30440220695a28c42daa23c13e192e36a20d03a2a79994e0fe1c3c6b612d0ae23743064602200ca19003e7c1ce0cecb0bbfba9a825fc3b83cf54e4c3261cd15f080d24a8a5b901] [3045022100aa9096ce71995c24545694f20ab0482099a98c99b799c706c333c521e51db66002206578f023fa46f4a863a6fa7f18b95eebd1a91fcdf6ce714e8795d902bd6b682b01] [522102b66fcb1064d827094685264aaa90d0126861688932eafbd1d1a4ba149de3308b21025cab5e31095551582630f168280a38eb3a62b0b3e230b20f8807fc5463ccca3c21021098babedb3408e9ac2984adcf2a8e4c48e56a785065893f76d0fa0ff507f01053ae]" 01000000010506344de69d47e432eb0174500d6e188a9e63c1e84a9e8796ec98c99b7559f70100000000ffffffff01c8af0000000000001976a91458b7a60f11a904feef35a639b6048de8dd4d9f1c88ac00000000

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

Validate and Broadcast the Transaction

Inspect the updated transaction visually.

$ bx tx-decode 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

transaction
{
    hash 7aa068cab7f11aa25f34f32bd7b3480790af2facdf8192c59985e6282c336465
    inputs
    {
        input
        {
            address 3A6oGpJ5MzABAj9PofXKjcpTJCgYrdGBNJ
            previous_output
            {
                hash f759759bc998ec96879e4ae8c1639e8a186e0d507401eb32e4479de64d340605
                index 1
            }
            script "zero [30440220695a28c42daa23c13e192e36a20d03a2a79994e0fe1c3c6b612d0ae23743064602200ca19003e7c1ce0cecb0bbfba9a825fc3b83cf54e4c3261cd15f080d24a8a5b901] [3045022100aa9096ce71995c24545694f20ab0482099a98c99b799c706c333c521e51db66002206578f023fa46f4a863a6fa7f18b95eebd1a91fcdf6ce714e8795d902bd6b682b01] [522102b66fcb1064d827094685264aaa90d0126861688932eafbd1d1a4ba149de3308b21025cab5e31095551582630f168280a38eb3a62b0b3e230b20f8807fc5463ccca3c21021098babedb3408e9ac2984adcf2a8e4c48e56a785065893f76d0fa0ff507f01053ae]"
            sequence 4294967295
        }
    }
    lock_time 0
    outputs
    {
        output
        {
            address 1966U1pjj15tLxPXZ19U48c99EJDkdXeqb
            script "dup hash160 [58b7a60f11a904feef35a639b6048de8dd4d9f1c] equalverify checksig"
            value 45000
        }
    }
    version 1
}

Notice that the endorsement script has been applied to transaction.inputs[0].script and that transaction.hash has been updated.

Validate the first endorsement of the transaction's first input, using the first public key, multisig script, first endorsement and transaction (optional).

$ bx input-validate 02b66fcb1064d827094685264aaa90d0126861688932eafbd1d1a4ba149de3308b "2 [02b66fcb1064d827094685264aaa90d0126861688932eafbd1d1a4ba149de3308b] [025cab5e31095551582630f168280a38eb3a62b0b3e230b20f8807fc5463ccca3c] [021098babedb3408e9ac2984adcf2a8e4c48e56a785065893f76d0fa0ff507f010] 3 checkmultisig" 30440220695a28c42daa23c13e192e36a20d03a2a79994e0fe1c3c6b612d0ae23743064602200ca19003e7c1ce0cecb0bbfba9a825fc3b83cf54e4c3261cd15f080d24a8a5b901 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

The endorsement is valid.

Validate the transaction against the blockchain (optional).

$ bx validate-tx 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

The transaction is valid.

Broadcast the transaction to the blockchain.

$ bx send-tx 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

Sent transaction at 2015-May-06 23:24:55.

Confirm Spend of Bitcoin

Look up the balance of the multisig address.

$ bx fetch-balance 3A6oGpJ5MzABAj9PofXKjcpTJCgYrdGBNJ

balance
{
    address 3A6oGpJ5MzABAj9PofXKjcpTJCgYrdGBNJ
    confirmed 0
    received 100000
    unspent 0
}

View the spend transaction on blockchain.info.