Term 1 S3 Lesson 4: Blockchain Data
Create Raw Transaction
Motivation for Creating Transactions
To really leverage the full power of the protocol, we need to bypass the GUI and work directly with the protocol.
Motivation for the Project
- Step 1 - View all unspent confirmed UTXO in the wallet
- Step 2 - View Details about a Specific UTXO
- Step 3 - Create a Raw Transaction
- Step 4 - Decode the Raw Transaction (to doublecheck it went through correctly)
- Step 5 - Sign the Raw Transaction
- Step 6 - Submit the Raw Transaction to the Network
- Step 7 - Query the TxID of the Transaction we sent
“Transaction life cycle”: Transaction - Wallet - Signature- Mempool - Network- Consensus - Hashing - block - Blockchain
Step 1
listunspent
- txid - This shows us that there is a Transaction with this id.
- vout - The Transaction has one output (vout at index 0).
- address - The Transaction is assigned to this address.
- account - This is a deprecated. It’s set to “ “ as a default.
- scriptPubKey - The hash of the Locking Script
- amount - Transaction amount in BTC
- confirmations - At the time of viewing this Tx, it has been confirmed 7 times (6 blocks added after it was added to the blockchain).
Step 2
gettxout
gettxout "txid" n ( include_mempool )
Arguments:
- “txid” (string, required) The transaction id
- “n” (numeric, required) vout number
- “include_mempool” (boolean, optional) Whether to include the mempool. Default: true. Note that an unspent output that is spent in the mempool won’t appear.
Step 3
createrawtransaction
createrawtransaction [{"txid":"id","vout":n},...] {"address":amount,"data":"hex",...} ( locktime ) ( replaceable )
Arguments
1. "inputs" (array, required) A json array of json objects
[
{
"txid":"id", (string, required) The transaction id
"vout":n, (numeric, required) The output number
"sequence":n (numeric, optional) The sequence number
}
,...
]
2. "outputs" (object, required) a json object with outputs
{
"address": x.xxx, (numeric or string, required) The key is the bitcoin address, the numeric value (can be string) is the BTC amount
"data": "hex" (string, required) The key is "data", the value is hex encoded data
,...
}
3. locktime (numeric, optional, default=0) Raw locktime. Non-0 value also locktime-activates inputs
4. replaceable (boolean, optional, default=false) Marks this transaction as BIP125 replaceable.
Allows this transaction to be replaced by a transaction with higher fees. If provided, it is an error if explicit sequence numbers are incompatible.
// CREATE RAW TRANSACTION
TXID = Get this from listunspent command
VOUT = Get this from listunspent command
ADDRESS = Where will this amount be sent
AMOUNT = How much BTC will be sent
createrawtransaction '[{"txid":"TXID","vout": VOUT}]''{"ADDRESS":AMOUNT}'
createrawtransaction '[{"txid": "50126e2761333ce429792e57bb756c9eaf5f51039242721316ee6e88ec10d8ac", "vout": 1}]' '{"2Mz2AhntMWhKoRiwSKRtt77XgJXstQREJZb":0.00008, "2MzJNqq3pRJuacB58wVCmuwWpse1nHUeAgQ":0.00851634}'`
0200000001acd810ec886eee161372429203515faf9e6c75bb572e7929e43c3361276e12500100000000ffffffff02401f00000000000017a9144a50bb39c22ba309f0ac1b81ad373f4886519f6c87b2fe0c000000000017a9144d6184fe9c6198131fd9020d729c53f32ef79f308700000000
(raw hex string of the tx)
Step 4. Decode Raw Transaction
decoderawtransaction"hexstring"
Step 5. Sign Raw Transaction
signrawtransaction "hexstring" ( [{"txid":"id","vout":n,"scriptPubKey":"hex","redeemScript":"hex"},...] ["privatekey1",...] sighashtype )
Arguments
1. "hexstring" (string, required) The transaction hex string
2. "prevtxs" (string, optional) An json array of previous dependent transaction outputs
[ (json array of json objects, or 'null' if none provided)
{
"txid":"id", (string, required) The transaction id
"vout":n, (numeric, required) The output number
"scriptPubKey": "hex", (string, required) script key
"redeemScript": "hex", (string, required for P2SH or P2WSH) redeem script
"amount": value (numeric, required) The amount spent
}
,...
]
3. "privkeys" (string, optional) A json array of base58-encoded private keys for signing
[ (json array of strings, or 'null' if none provided)
"privatekey" (string) private key in base58-encoding
,...
]
4. "sighashtype" (string, optional, default=ALL) The signature hash type. Must be one of
"ALL"
"NONE"
"SINGLE"
"ALL|ANYONECANPAY"
"NONE|ANYONECANPAY"
"SINGLE|ANYONECANPAY"
Build Out Command
// SIGN RAW TRANSACTION
TRANSACTION HASH = Get from result of createrawtransaction command
TXID = Get from listunspent command
VOUT (optional) = Get from listunspent command
SCRIPT PUB KEY (optional) = Get from createrawtransaction command
PRIVATE KEY (optional) = Get from wallet
// Use the values you’ve collected above to fill in the signrawtransaction command
signrawtransaction 'TRANSACTION_HASH_HERE''[{"txid":"TXID_HERE","vout":VOUT_HERE,"scriptPubKey":"SCRIPT_PUB_KEY_HERE"}]''["PRIVATE_KEY"]'

signrawtransactionis deprecated and will be fully removed in v0.18. To usesignrawtransactionin v0.17, restartbitcoindwith-deprecatedrpc=signrawtransaction.
Projects should transition to usingsignrawtransactionwithkeyandsignrawtransactionwithwalletbefore upgrading to v0.18 (code -32)
Step 6. Send Raw Transaction
sendrawtransaction "hexstring" ( allowhighfees )
Arguments
1. "hexstring" (string, required) The hex string of the raw transaction)
2. allowhighfees (boolean, optional, default=false) Allow high fees
Result
"hex" (string) The transaction hash in hex
sendrawtransaction 02000000000101acd810ec886eee161372429203515faf9e6c75bb572e7929e43c3361276e12500100000017160014ece4a6d95ac9f7cd0ace4784f66e20cb15f24be9ffffffff02401f00000000000017a9144a50bb39c22ba309f0ac1b81ad373f4886519f6c87b2fe0c000000000017a9144d6184fe9c6198131fd9020d729c53f32ef79f30870247304402203cb459580529475124f0906c0c482c2fb99e0ad1e47596f5dc03789938ad5c14022067714a9589a2e09d9362df06c807fea540e3961b7e3dc42a7ff25f604b1158f4012103a852c77aabfa72c821bffda3ba83c6c91416f874ea638cc7ff8ec4c5e65e5b9a00000000
got:
2873e08edc78cbe1b9dbf2183ac625ac946d0f17e05401d6dfc01a6ddbb403d8
(txid)
Step 7. Query the TxID
gettransaction "txid" ( include_watchonly )
1. "txid" (string, required) The transaction id
2. "include_watchonly" (bool, optional, default=false) Whether to include watch-only addresses in balance calculation and details[]
Summary
- Step 1 - View all unspent confirmed UTXO in the wallet
- listunspent - Show all the unspent confirmed outputs in our wallet)
- Step 2 - View Details about a Specific UTXO
- gettxout - Get the details of this unspent output above
- Step 3 - Create a Raw Transaction
- createrawtransaction - Create a transaction
- Step 4 - Decode the Raw Transaction (to double-check it went through correctly)
- decoderawtransaction - View raw hex string that encodes the transaction details we supplied
- Step 5 - Sign the Raw Transaction
- signrawtransaction - Sign the transaction
- Step 6 - Submit the Raw Transaction to the Network
- sendrawtransction - Takes the raw hex string produced by signrawtransaction and returns a transaction hash (txid) as it submits the transaction on the network.
- Step 7 - Query the TxID of the Transaction we sent
- gettransaction - Query the TxID and view details. Similar to online block explorer
Embedding Data in Bitcoin Core
OP_RETURN
- Stores up to 40 bytes
- Recorded in Blockchain
- Does not bloat UTXO memory pool