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Home CyberConverge 2026 Two Locks, One Message
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Two Locks, One Message

Two Locks, One Message

  • Author: Sagnik

This is a cryptography-based CTF using two layers of encryption: a Caesar cipher and XOR.

From clue.txt, we determine the Caesar shift is 3 and the XOR key is 42 (0x2A).

A simple google search gives you the second lock key. :D

Since the message was encrypted twice, we reverse the operations during decryption.

The encrypted data is:

1
6c687c514c1e425c1e5f754b1a5f75184b57

First, undo the XOR layer using key 2A:

1
FBV{f4hv4u_a0u_2a}

Then undo the Caesar shift by shifting the letters back by 3:

1
CYS{c4es4r_x0r_2x}

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CYS{c4es4r_x0r_2x}
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