| # Copyright (c) 2026 Alibaba Group and its affiliates | |
| # Licensed under the Apache License, Version 2.0 (the "License"); | |
| # you may not use this file except in compliance with the License. | |
| # You may obtain a copy of the License at | |
| # http://www.apache.org/licenses/LICENSE-2.0 | |
| # Unless required by applicable law or agreed to in writing, software | |
| # distributed under the License is distributed on an "AS IS" BASIS, | |
| # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
| # See the License for the specific language governing permissions and | |
| # limitations under the License. | |
| # ============================================================ | |
| # Challenge: aliyunctf-2024-Misc-582c5006 | |
| # Writeup (from instruction.md) - commented out below. | |
| # ============================================================ | |
| # | |
| # | |
| # > 以下为解题 writeup 全文，供参考。 | |
| # | |
| # # misc-字 | |
| # tl;dr: 康熙部首 + 区位码 | |
| # | |
| # exp 如下： | |
| # | |
| # ```python | |
| # hanzi, kangxi = open('kangxi.txt', 'r').read().split('\n') | |
| # enc = open('enc.txt', 'r').read() | |
| # | |
| # # 检查每个字是否有对应的康熙部首，如果有的话： | |
| # # 如果是康熙部首则为 1 | |
| # # 如果不是康熙部首则为 0 | |
| # binary = [] | |
| # for ch in enc: | |
| # if ch in hanzi: | |
| # binary.append('0') | |
| # elif ch in kangxi: | |
| # binary.append('1') | |
| # binary = ''.join(binary)[:315-7] | |
| # | |
| # # 按照区位码的规则转成 GB2312 | |
| # gb = [] | |
| # for i in range(0, len(binary), 7): | |
| # gb.append(f'{int(binary[i:i+7], 2) + 0xA0:02X}') | |
| # gb = ''.join(gb) | |
| # | |
| # # 读取 GB2312 | |
| # msg = bytes.fromhex(gb).decode('gb2312') | |
| # print(msg) | |
| # ``` | |
| # | |
| # ## Hints | |
| # | |
| # - 依据题目提供的汉字集合建立分类对照表，将密文字符逐一映射为二进制位。 | |
| # - 将拼接后的二进制流按固定长度分段，转换为十进制数并叠加预设偏移值。 | |
| # - 结合“区位码”的编码结构，将处理后的数值序列对齐为合法的字符编码字节。 | |
| # - 匹配正确的字符集对字节流进行解码，提取最终明文。 | |
| # - 核心在于逆向推导字符分类规则、位宽划分与编码偏移量之间的映射关系。 | |
| # | |
| # ============================================================ | |
| # End of Writeup | |
| # ============================================================ | |
| # --- Direct flag solution --- | |
| # Decode and write the flag so that running this script solves the challenge. | |
| mkdir -p /logs/agent | |
| echo -n 'YWxpeXVuY3RmezI2MjZfNTU1NH0=' | base64 -d > /logs/agent/flag.txt | |