gettxoutproof
NOTE: By default this function only works sometimes. This is when there is an unspent output in the utxo for this transaction. To make it always work, you need to maintain a transaction index, using the -txindex command line option or specify the block in which the transaction is included manually (by blockhash).
Argument #1-txids
Type: json array, Required
Description: The txids to filter
[
"txid", (string) A transaction hash
...
]
Argument #2-blockhash
Type: string, Optional
Description: If specified, looks for txid in the block with this hash
Result
Type: string (hex)
Description: A string that is a serialized, hex-encoded data for the proof.