test

main.py

@@ -0,0 +1,92 @@
+# objective: process transactions, validate them, mine them to a block
+# input: ./mempool
+# output: output.txt
+
+# difficulty target: 0000ffff00000000000000000000000000000000000000000000000000000000
+
+# output format:
+# block header
+# serialized coinbase transaction
+# txids of the transactions mined in the block
+
+import json
+import os
+import hashlib
+
+from ecdsa import VerifyingKey, SECP256k1, BadSignatureError
+from ecdsa.util import sigdecode_der
+
+def serialize_transaction(transaction):
+    prevout = transaction['vin'][0]['prevout']
+    scriptpubkey_type = prevout['scriptpubkey_type']
+
+    if scriptpubkey_type == 'v0_p2wpkh':
+        serialized_tx = f"{prevout['value']}{prevout['scriptpubkey']}"
+    else:
+        serialized_tx = json.dumps(transaction, sort_keys=True)
+
+    return serialized_tx
+
+def double_hash256(data):
+    return hashlib.sha256(hashlib.sha256(data.encode()).digest()).digest()
+
+def load_transactions(mempool_dir):
+    transactions = []
+    for filename in os.listdir(mempool_dir):
+        if filename.endswith('.json'):
+            with open(os.path.join(mempool_dir, filename), 'r') as file:
+                try:
+                    transaction = json.load(file)
+                    if validate_transaction(transaction):
+                        transactions.append(transaction)
+                except json.JSONDecodeError:
+                    continue
+    return transactions
+
+def validate_transaction(transaction):
+  try:
+    txid = transaction['vin'][0]['txid']
+    signature_hex = transaction['vin'][0]['witness'][0]
+    public_key_hex = transaction['vin'][0]['witness'][1]
+
+    sighash_type = signature_hex[-2:]
+    signature_bytes = bytes.fromhex(signature_hex[:-2])
+
+    serialized_tx = serialize_transaction(transaction)
+    serialized_tx += sighash_type
+
+    message_hash = double_hash256(serialized_tx)
+
+    vk = VerifyingKey.from_string(bytes.fromhex(public_key_hex), curve=SECP256k1)
+    return vk.verify(signature_bytes, message_hash, sigdecode=sigdecode_der)
+  except (KeyError, ValueError, BadSignatureError):
+    return False
+
+def mine_block(transactions, difficulty_target):
+    block_data = "".join(tx['id'] for tx in transactions)
+    nonce = 0
+    while True:
+        block_header = f'{block_data}{nonce}'
+        block_hash = hashlib.sha256(block_header.encode()).hexdigest()
+        if block_hash < difficulty_target:
+            break
+        nonce += 1
+    return nonce, block_hash
+
+def write_output(block_hash, transactions):
+    with open("output.txt", "w") as f:
+        f.write(f"Block Hash: {block_hash}\n")
+        f.write("Serialized Coinbase Transaction\n")
+        for tx in transactions:
+            f.write(f"{tx['id']}\n")
+
+def main():
+    mempool_dir = "mempool"
+    transactions = load_transactions(mempool_dir)
+    difficulty_target = "0000ffff00000000000000000000000000000000000000000000000000000000"
+    _, block_hash = mine_block(transactions, difficulty_target)
+    write_output(block_hash, transactions)
+
+if __name__ == "__main__":
+    main()
+

run.sh

@@ -1 +1,3 @@
-# Update this file to run your own code
+# Update this file to run your own code
+pip install ecdsa
+python main.py