Description#

Given an encrypted string that appears to use unusual Unicode characters.

Analysis#

The challenge name “65536” is a strong hint pointing to Base65536 encoding - a binary encoding scheme that uses Unicode characters from the Basic Multilingual Plane (BMP). Unlike traditional base64 which uses 64 ASCII characters, base65536 uses 65,536 different Unicode characters, making it highly compact but visually unusual.

The encrypted string:

硓硓欲橻𖤴鐴楴鑵𖥮鐴楢桳歟𠌴

Solution#

Install the base65536 library and decode:

pip install base65536

Python solution:

import base65536

crypto = "硓硓欲橻𖤴鐴楴鑵𖥮鐴楢桳歟𠌴"
flag = base65536.decode(crypto).decode()
print(flag)

Output:

SCSCC26{54y4_t4u_ny4_b4s3_64}