def read_txout(data, decompress=False):
value_compressed, offset = base.read_varint(data)
value = decompress_value(value_compressed)
script = decompress_script(data[offset:]) if decompress else read_script(
data[offset:])
return (script, value)
def read_coin(data, decompress=False):
code, offset = base.read_varint(data)
block_height = code >> 1
is_coinbase = code & 1
txout = read_txout(data[offset:], decompress)
return (block_height, txout, is_coinbase)
def classify_compressed_script(script, is_obfuscated_snapshot=False):
is_compressed = True
res = None
if script[0] == 0x00: # P2PKH
res = ScriptType.P2PKH
elif script[0] == 0x01: # P2SH
res = ScriptType.P2SH
elif script[0] in [0x02, 0x03]: # P2PK compressed
res = ScriptType.P2PK_COMP
elif script[0] in [0x04, 0x05]: # P2PK uncompressed
res = ScriptType.P2PK_NONC
else: # No compressable script, fall back to uncompressed classification
if is_obfuscated_snapshot:
if script[0] == 0x06:
res = ScriptType.CoinpruneP2PKH
elif script[0] == 0x07:
res = ScriptType.CoinpruneP2SH
elif script[0] == 0x08:
res = ScriptType.CoinpruneP2WPKH
elif script[0] == 0x09:
res = ScriptType.CoinpruneP2WSH
if res is None:
is_compressed = False
len_script, offset = base.read_varint(script)
res = classify_uncompressed_script(script[offset:(offset +
len_script)])
if res == ScriptType.OTHER:
log.error(
f'Detected OTHER script: {hexlify(script)} vs. {hexlify(script[offset:(offset + len_script)])}'
)
log.error(f'Len script: {len_script}, Offset: {offset}')
return res, is_compressed
def read_script(data):
size, _ = base.read_varint(data)
if size < SPECIAL_SCRIPTS:
size = 20 if size in [0, 1] else 32
else:
size -= SPECIAL_SCRIPTS
return data[:(size + 1)]
def get_script_payload_compressed(script, is_obfuscated_snapshot=False):
_, is_compressed = classify_compressed_script(
script, is_obfuscated_snapshot=is_obfuscated_snapshot)
if is_compressed:
return script[1:]
else:
len_script, offset = base.read_varint(script)
return get_script_payload_uncompressed(script[offset:(offset +
len_script)])
def decompress_script(
data,
is_obfuscated_snapshot=False): # see bitcoin core compressor.h:63
size, offset = base.read_varint(data)
data = data[offset:]
if size < SPECIAL_SCRIPTS:
case = size
size = 20 if size in [0, 1
] else 32 # see bitcoin core compressor.cpp:87
script_payload = data[:size]
return decompress_payload(
case,
script_payload,
is_obfuscated_snapshot=is_obfuscated_snapshot)
elif script_type == ScriptType.P2WPKH:
case = SPECIAL_SCRIPTS + 0x02
elif script_type == ScriptType.P2WSH:
case = SPECIAL_SCRIPTS + 0x03
res = bytes([case]) + payload
obfuscated = True
compressed = True
elif script_type in [ScriptType.P2PK_NONC, ScriptType.P2PK_COMP
] and is_compressed:
res = script
obfuscated = False
compressed = True
else:
res = script
res, offset = base.read_varint(script)
res = script[offset:]
res = base.write_varint(SPECIAL_SCRIPTS + 4 + len(res)) + res
obfuscated = False
compressed = is_compressed
add_case(script_type)
return res, obfuscated, compressed
def obfuscate_compressed_script_file(file_handler, script):
script_new, _, _ = obfuscate_compressed_script(script)
file_handler.write(script_new)