SICTF 2023 Round#3 团队赛 Blockchain 方向个人题解

CheckinNewYear

先看一眼合约，并不复杂，就一签到题：

// SPDX-License-Identifier: shu shao de xiao mi di
pragma solidity ^0.8.9;
contract HappyNewYear{
    string private NewYear;
    constructor(string memory _newyear )  {
        NewYear = _newyear;
    }
    function happyNewYear(string memory _newYear) public payable {
        require(uint160(msg.sender) |
        2**16 * 3**3 * 5 * 7 * 13 * 17 * 19 * 37 * 73 * 97 * 109 * 241 * 257 * 433 * 577 * 673 * 38737 * 487824887233 == 2**2 * 17 * 67 * 733 * 316139 * 18992431891 * 72887484710091183279372959, "Not this Year");
        NewYear = _newYear;
    }
    function isSolved() public view returns (bool){
        require(keccak256(abi.encodePacked(NewYear)) == keccak256(abi.encodePacked("Happy")),"not HappyNewYear");
        return true;
    }
}

唯一的要点可能就是钱包地址需要满足一定的要求，不过这要求也不算严格，问题不大：

from web3 import Account

while True:
    account = Account.create()
    address = account.address
    address_int = int(address, 16)
    private_key = account._private_key.hex()
    if address_int | 1461501637330902918203684832716283019655932477440 == \
            1461501637330902918203684832716283019655932485668:
        break
print(f"{address=}", f"{private_key=}", sep="\n")

# address='0xf10DBbeAa1C8fE5971610fac5768E91DDe732024'
# private_key='0xf288cac72c6c753e2251b334a07ba40c054e072e4f20fdd763bf8e25f5fb9274'

拿着合约源代码生成个 ABI，然后操作合约就可以了。具体的代码在之前的区块链题解中有，咱也是复制过来改一下：

with open("contract_abi.json", "r") as abi_file:
    contract_abi = json.load(abi_file)
contract = w3.eth.contract(address=contract_address, abi=contract_abi)

def send_transaction(transaction, private_key):
    signed_transaction = w3.eth.account.sign_transaction(
        transaction, private_key)
    transaction_hash = w3.eth.send_raw_transaction(
        signed_transaction.rawTransaction)
    w3.eth.wait_for_transaction_receipt(transaction_hash)
    return transaction_hash

def happy_new_year(wallet_address: str, private_key: str):
    transaction = contract.functions.happyNewYear("Happy").build_transaction({
        "chainId": 39813,
        "maxFeePerGas": w3.to_wei(1.000000014, 'gwei'),
        "maxPriorityFeePerGas": w3.to_wei(1, 'gwei'),
        "gas": 0x200000,
        "value": w3.to_wei(0, 'ether'),
        "nonce": w3.eth.get_transaction_count(wallet_address),
    })
    return send_transaction(transaction, private_key)

Tags: #CTF #Writeup #Blockchain #SICTF

This article is authored by luoingly and licensed under CC BY-NC 4.0

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