[2025青海民族大学新生赛] re misc crypto _部分wp

re

你的flag被加密啦！

可以直接改源码

点击查看代码

def custom_encrypt(plaintext):encrypted = ""key = [3, 5, 2]key_index = 0for char in plaintext:if 'a' <= char <= 'z':shift = key[key_index]new_char = chr((ord(char) - ord('a') - shift) % 26 + ord('a'))key_index = (key_index + 1) % len(key)elif 'A' <= char <= 'Z':shift = key[key_index]new_char = chr((ord(char) - ord('A') + shift) % 26 + ord('A'))key_index = (key_index + 1) % len(key)elif '0' <= char <= '9':num = int(char)new_num = (num - 7) % 10new_char = str(new_num)else:new_char = charencrypted += new_charreturn encryptedencrypted_flag = custom_encrypt("iqcj{qafmgh89991}")
print("加密后的flag是:", encrypted_flag)

crypto

CTF

运行附件得到

加密后的 flag: GzSkR/OLfsenxQd5Hh4t2RlEwL/3JG5dW/gYu7YI1Os=
密钥（Base64 编码）: MTIzNDUAAAAAAAAAAAAAAA==
IV（Base64 编码）: MTIzNDU2AAAAAAAAAAAAAA==
加密模式: AES - CBC

可以直接找合适的在线解密
注意都是base64

https://tool.hiofd.com/aes-decrypt-online/

新年快乐

点击查看代码

aa='Gsv_Bvzi_lu_gsv_Hmzpv_rh_zfhkrxrlfh'
flag=""
for i in aa:if 'a'<= i <= 'z':new = chr(ord('z')-ord(i)+ord('a'))flag += newelif 'A'<= i <='Z':new = chr(ord('Z')-ord(i)+ord('A'))flag += newelse:new=iflag += new
print(flag)

misc

come on

wenshilou

foremost分离文件，zip里面有flag.txt，base64解码

好看的照片

foremost分离文件，zip的密码根据txt的提示对照ASCII码表解决
密码为：7Fx.
分离出来是9张照片，拼接为一张二维码，扫码

失落遗迹的神秘预言

浏览器搜索维吉尼，发现是维吉尼密码，密钥为HERO，在线解码

https://www.qqxiuzi.cn/bianma/weijiniyamima.php
然后还后栅栏密码

喔艾亭嘟歌

直接用Audacity打开，标签轨有内容，base4解密