Added BTGC marker and file name to OP_RETURN

markrussinovich · Feb 20, 2022 · 2385657 · 2385657
1 parent 47e84e4
commit 2385657
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Showing 3 changed files with 122 additions and 25 deletions.
diff --git a/main.py b/main.py
@@ -1,4 +1,27 @@
-
+#
+# BTC Graffiti
+# by Mark Russinovich
+#
+# Copyright (c) 2022 by Mark Russinovich
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+# THE SOFTWARE.
+#
 from email.mime import image
 import sys
 from utils.transaction import *
@@ -18,12 +41,11 @@
 # parse_commandline
 # read arguments
 #
-def parse_commandline():
-    parser = argparse.ArgumentParser(prog='btcgraffiti', description='A script that encodes the specified image and posts a transaction to the Bitcoin blockchain')
-    parser.add_argument('file', metavar='file', help='name of file to post or to decode into')
-    group = parser.add_mutually_exclusive_group()
-    group.add_argument('--key', "-k", help='Account key' )
-    group.add_argument('--transaction', "-tx", help='Transaction to decode' )
+def parse_commandline(descriptiontext):
+    parser = argparse.ArgumentParser(prog='btcgraffiti', 
+        description=descriptiontext)
+    parser.add_argument('fileortransaction', metavar='<file|transaction>', help='name of file to post or to decode into')
+    parser.add_argument('--key', "-k", help='Account key. Required for encoding data' )
     parser.add_argument('--net', "-n", default='main', choices=['main', 'test'], help='Either \'test\' or \'main\'' )
     args = parser.parse_args()    
     return args
@@ -34,14 +56,17 @@ def parse_commandline():
 #
 def main():
     sys.tracebacklimit=0
-    args = parse_commandline()
+    descriptiontext='Write data into Bitcoin transactions and read data from them.'
+    print( '\nBTC Graffiti - by Mark Russinovich (@markrussinovich)')
+    print( descriptiontext, '\n')
+    args = parse_commandline( descriptiontext )
 
     # either encode or decode
     if args.key != None:
-        encode_to_btc( args.key, args.net, args.file )
+        encode_to_btc( args.key, args.net, args.fileortransaction )
     else:
-        decode_from_btc( args.transaction, args.net, args.file )
-
+        decode_from_btc( args.fileortransaction, args.net )
+    print('')
 
 if __name__ == "__main__":
     main()
diff --git a/src/decode.py b/src/decode.py
@@ -1,3 +1,27 @@
+#
+# BTC Graffiti
+# by Mark Russinovich
+#
+# Copyright (c) 2022 by Mark Russinovich
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+# THE SOFTWARE.
+#
 from email.mime import image
 import sys
 from src.encode import HASH_SIZE
@@ -30,35 +54,56 @@ def decode_txout( txout: TxOut ):
         return None
     return txout.script_pubkey.cmds[2]
 
+#
+# verify_btcgmarker
+#
+def verify_btcgmarker( txouts ):
+    for i in range(len(txouts)):
+        cmds = txouts[i].script_pubkey.cmds
+        if len(cmds) == 2 and isinstance(cmds[0], int) and OP_CODE_NAMES[cmds[0]] == 'OP_RETURN':
+            return txouts[i].script_pubkey.cmds[1]
+    return None
 
 #
 # decode_file
-# decode the transaction outputs into a file
+# decode the transaction outputs into a file.
+# returns the OP_RETURN message
 #
-def decode_file( txouts, file ):
+def decode_file( txouts ):
     filebytes = []
 
-    # ignore last txout which is the miner fee
-    for i in range(len(txouts)-1):
+    # make sure this is one of ours by looking for marker in OP_RETURN
+    btcgmarker = verify_btcgmarker( txouts ) 
+    if btcgmarker == None:
+        print( 'Error: Not a BTC Graffiti transaction.')   
+        quit()
+    filename = str(btcgmarker[5:], 'utf-8')
+    print( 'Writing encoded data to', filename)
+
+    # ignore last two txouts: last one is the OP_RETURN message
+    # and second to last is remainding unspent
+    for i in range(len(txouts)-2):
         filebytes += bytes(decode_txout(txouts[i]))
     filelen = decode_int(BytesIO(bytes(filebytes[0:])), 4)
 
     if len(filebytes)-4 > filelen + HASH_SIZE or len(filebytes)-4 < filelen - HASH_SIZE:
         print('Error: Unrecognized encoding.')
         quit()
     try:
-        f = open(file, 'wb')
+        f = open(filename, 'wb')
         f.write( bytes(filebytes[4:4+filelen]))
+        f.close()
     except IOError as e:
-        print('Error writing ', file, ': ', e )
+        print('Error writing ', filename, ': ', e )
         raise
+    return filename
 
 
 #
 # decode_from_btc
 # decode a transaction to extract media content
 #
-def decode_from_btc( tx, net, file ):
+def decode_from_btc( tx, net ):
     print( 'Reading transaction...')
     if net == 'main':
         txbytestring = NetworkAPI.get_transaction_by_id( tx )
@@ -67,6 +112,6 @@ def decode_from_btc( tx, net, file ):
     txbytes = bytes.fromhex(txbytestring)
     tx = Tx.decode(BytesIO(txbytes))
 
-    print( 'Writing encoded data to file...')
-    decode_file( tx.tx_outs, file )
-    print('Transaction decoded to ', file)
+    # writ to file
+    filename = decode_file( tx.tx_outs )
+    print('Transaction decoded to', str(filename) )
diff --git a/src/encode.py b/src/encode.py
@@ -1,3 +1,27 @@
+#
+# BTC Graffiti
+# by Mark Russinovich
+#
+# Copyright (c) 2022 by Mark Russinovich
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+# THE SOFTWARE.
+#
 from email.mime import image
 import sys
 from utils.transaction import *
@@ -87,16 +111,19 @@ def encode_to_btc( key, net, file ):
         key = PrivateKeyTestnet( key ) 
     else:
         key = PrivateKey( key )
-    print('Looking up account balance for ', key.address, '...' )
+    print('Looking up account balance for', key.address, '...' )
     if( float(key.get_balance('btc')) < 0.0001 ):
-        print( 'Not enough funds in account', key.address, ' for transaction:\n')
+        print( 'Not enough funds in account', key.address, 'for transaction:\n')
 
     # fire off the transaction!
     try: 
-        txid = key.send( txouts )
+        # save marker and file name in OP_RETURN
+        filepath = os.path.split(file)
+        btcgmessage='BTGC:'+filepath[1] 
+        txid = key.send( txouts, message=btcgmessage )
     except Exception as inst:
         print( inst )
         return 
 
-    print('File encoded to transaction ', txid )
+    print('File encoded to transaction', txid )
     return