8545 solve

DownUnderCTF 2023/blockchain/Eight Five Four Five/solve.py

@@ -0,0 +1,78 @@
+from web3 import *
+from solcx import * # py-solc-x
+from web3.middleware import geth_poa_middleware
+
+install_solc()
+# Initialize Vars
+node_url = "https://blockchain-eightfivefourfive-3e45438902cf45cf-eth.2023.ductf.dev:8545"
+contract_address = "0xf22cB0Ca047e88AC996c17683Cee290518093574"
+
+# Initialize the address calling the functions/signing transactions
+player_address = "0x6BECafE7B0520Ad68E37c9A66Fd748b1204c1087"
+private_key = "0xd660674d680ec9f24931ae685ebb065ebe89248f02caa91d02cb5db10ddefbdc"  # To sign the transaction
+
+src = compile_source("""
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.19;
+
+contract EightFiveFourFive {
+    string private use_this;
+    bool public you_solved_it = false;
+
+    constructor(string memory some_string) {
+        use_this = some_string;
+    }
+
+    function readTheStringHere() external view returns (string memory) {
+        return use_this;
+    }
+
+    function solve_the_challenge(string memory answer) external {
+        you_solved_it = keccak256(bytes(answer)) == keccak256(bytes(use_this));
+    }
+
+    function isSolved() external view returns (bool) {
+        return you_solved_it;
+    }
+}
+""",output_values=['abi', 'bin'])
+
+
+def get_nonce():
+    return web3.eth.get_transaction_count(player_address)
+
+contract_id, contract_interface = src.popitem()
+abi = contract_interface['abi']
+# Create the node connection
+web3 = Web3(Web3.HTTPProvider(node_url))
+web3.middleware_onion.inject(geth_poa_middleware, layer=0)
+# Verify if the connection is successful
+if web3.is_connected():
+    print("-" * 50)
+    print("Connection Successful", web3.eth.chain_id)
+    print("-" * 50)
+else:
+    print("Connection Failed")
+
+# Initialize address nonce
+nonce = web3.eth.get_transaction_count(player_address)
+
+code = web3.eth.get_code(contract_address)
+
+# Create smart contract instance
+contract = web3.eth.contract(address=contract_address, abi=abi)
+
+# initialize the chain id, we need it to build the transaction for replay protection
+Chain_id = web3.eth.chain_id
+
+answer = contract.functions.readTheStringHere().call()
+print("answer = ", answer)
+
+trx = contract.functions.solve_the_challenge(str(answer)).build_transaction({'from':player_address, 'nonce':get_nonce(), 'gasPrice':1})
+print(trx)
+strans = web3.eth.account.sign_transaction(trx, private_key)
+web3.eth.send_raw_transaction(strans.rawTransaction)
+
+print("isSolved = ", contract.functions.isSolved().call())
+
+pass