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#!/usr/bin/env python3
"""Create a Bitflash UTXO inclusion proof from local blk*.dat files.
The proof is deliberately outside consensus. It proves that one txid:vout is
included in the deterministic UTXO root produced by verify-utxo-set.py.
"""
import argparse
import hashlib
import json
import sys
from pathlib import Path
import bitflash_chain as chain
SCHEMA = "bitflash-utxo-inclusion-proof-1"
def canonical_bytes(obj):
return (json.dumps(obj, sort_keys=True, separators=(",", ":"), ensure_ascii=True) + "\n").encode("ascii")
def split_outpoint(outpoint):
parts = outpoint.split(":")
if len(parts) != 2 or len(parts[0]) != 64:
raise SystemExit("outpoint must be txid:vout")
try:
vout = int(parts[1], 10)
except ValueError:
raise SystemExit("vout must be a decimal integer")
if vout < 0:
raise SystemExit("vout must not be negative")
return parts[0].lower(), vout
def build_merkle_proof(keys, leaf_hashes, index):
current_index = index
layer = list(leaf_hashes)
proof = []
level = 0
while len(layer) > 1:
if current_index % 2 == 0:
sibling_index = current_index + 1
duplicated = sibling_index >= len(layer)
sibling = layer[current_index] if duplicated else layer[sibling_index]
side = "right"
else:
sibling_index = current_index - 1
duplicated = False
sibling = layer[sibling_index]
side = "left"
proof.append({
"level": level,
"side": side,
"hash": sibling.hex(),
"duplicated": duplicated,
})
next_layer = []
for i in range(0, len(layer), 2):
left = layer[i]
right = layer[i + 1] if i + 1 < len(layer) else left
next_layer.append(hashlib.sha256(chain.UTXO_NODE_DOMAIN + left + right).digest())
layer = next_layer
current_index //= 2
level += 1
return proof, layer[0].hex()
def build_proof(args):
txid, vout = split_outpoint(args.outpoint)
outpoint = "%s:%d" % (txid, vout)
raw_blocks = chain.read_blocks(args.datadir, args.max_blocks)
if not raw_blocks:
raise SystemExit("no Bitflash blocks found in %s" % args.datadir)
try:
blocks = chain.select_main_chain(raw_blocks)
state = chain.apply_blocks(blocks, strict_duplicates=args.strict_duplicates)
except chain.ParseError as e:
raise SystemExit(str(e))
utxos = state["utxos"]
stats = state["stats"]
if outpoint not in utxos:
raise SystemExit("outpoint is not unspent in the scanned chain: %s" % outpoint)
keys = sorted(utxos)
leaf_hashes = [chain.utxo_leaf_hash(k, utxos[k]) for k in keys]
index = keys.index(outpoint)
proof_path, root = build_merkle_proof(keys, leaf_hashes, index)
direct_root = chain.utxo_root(utxos)
if root != direct_root:
raise SystemExit("internal proof root mismatch")
tip = blocks[-1]
utxo = utxos[outpoint]
report = {
"schema": SCHEMA,
"deterministic": True,
"chain": {
"name": "Bitflash",
"ticker": "BTF",
"message_start_hex": chain.MAGIC.hex(),
"coin": chain.COIN,
},
"commitment": {
"algorithm": "sorted-outpoint-merkle-sha256",
"leaf_domain": chain.UTXO_LEAF_DOMAIN,
"node_domain": chain.UTXO_NODE_DOMAIN_TAG,
"root": root,
"leaf_count": len(keys),
},
"target": {
"outpoint": outpoint,
"txid": txid,
"vout": vout,
"leaf_index": index,
"leaf_hash": leaf_hashes[index].hex(),
"utxo": utxo,
},
"proof": proof_path,
"scanned": {
"raw_block_count": len(raw_blocks),
"side_blocks_ignored": len(raw_blocks) - len(blocks),
"main_chain_block_count": len(blocks),
"first_height": 0,
"last_height": len(blocks) - 1,
"tip_hash": tip["hash"],
"tip_time": tip["time"],
"tip_time_utc": tip["time_utc"],
},
"warnings": {
"legacy_duplicate_output_overwrites": len(stats["duplicate_outputs"]),
},
"verdict": "UTXO_INCLUSION_PROOF_CREATED",
}
return report
def print_text(proof):
data_hash = hashlib.sha256(canonical_bytes(proof)).hexdigest()
target = proof["target"]
utxo = target["utxo"]
print("Bitflash UTXO inclusion proof")
print("schema: %s" % proof["schema"])
print("canonical proof sha256: %s" % data_hash)
print()
print("Target")
print(" outpoint: %s" % target["outpoint"])
print(" value: %s BTF" % utxo["value_btf"])
print(" height: %d" % utxo["created_height"])
print(" index: %d of %d" % (target["leaf_index"], proof["commitment"]["leaf_count"]))
print()
print("Commitment")
print(" root: %s" % proof["commitment"]["root"])
print(" path: %d sibling hashes" % len(proof["proof"]))
print(" tip: %s" % proof["scanned"]["tip_hash"])
print()
print("Verdict: %s" % proof["verdict"])
def main(argv):
ap = argparse.ArgumentParser(description=__doc__)
ap.add_argument("outpoint", help="unspent output to prove, as txid:vout")
ap.add_argument("--datadir", default=chain.default_datadir(), help="Bitflash data directory")
ap.add_argument("--max-blocks", type=int, default=0,
help="number of blocks to scan; 0 means all block files")
ap.add_argument("--strict-duplicates", action="store_true",
help="fail instead of using legacy last-write-wins duplicate output handling")
ap.add_argument("--json", action="store_true", help="print canonical JSON")
ap.add_argument("--out", help="write canonical JSON proof to this path")
args = ap.parse_args(argv)
proof = build_proof(args)
data = canonical_bytes(proof)
if args.out:
Path(args.out).write_bytes(data)
if args.json:
sys.stdout.buffer.write(data)
else:
print_text(proof)
return 0
if __name__ == "__main__":
raise SystemExit(main(sys.argv[1:]))
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