[Mission] The UAC Substitution Cipher

🎯 The UAC Substitution Cipher (Crypto · Level 3 · +150 XP)

Kris's custom UAC cipher combines base64 encoding, MD5 key expansions, string reversals, and two proprietary secret substitution tables. Analyze an intercepted ciphertext and learn where custom ciphers fall short against frequency analysis.

Learning & Defense Goals:

• Analyze ciphertext structure and reversal passes
• Trace the substitution alphabet pattern
• Decrypt the hidden flag and review modern authenticated encryption

🎯 Launch Isolated Sandbox on Cyber Lab →

Community Discussion Rules: Discuss methodologies, discovery tactics, and architectural hardening. Please do not post raw flags directly. Share your production remediation code!