Quantum Cryptography Challenge

Decrypt quantum-secure ciphers by exploiting classical vulnerabilities. Master RSA, AES, XOR, and timing attacks in a professional security environment.

Difficulty
Medium-Hard
Points
500
Vulnerabilities
5+
Time
30-45 min
API Explorer CLI Interface Exploit Script Guide

Cryptography Mastery Path

Stage 0 of 6 0% Complete
1
Weak RSA Factorization
2
AES-ECB Pattern Leakage
3
CBC Padding Oracle
4
XOR Stream Cipher Reuse
5
HMAC Timing Attack
6
Final Flag Assembly
Stage 1: Weak RSA Factorization
Next: ECB Pattern Analysis
+50 Points
Challenge Ciphertext
J5anCYyDCRWB31AKrYhXd28eHbZT1v/8fpI7isDzmtUfhONCPCfJT8aWm70r0wWQDd6J+Z7qGSAsELTdqM6eRYWF879c4uTup1AaHq6eu4MTiF+TAsdOjBcT2PbRQqJdgvPxvKSkOhGnk3LXz4Ws7caoozxq/DtObC3/6wUBd7g=

Recommended Tool

yafu, msieve, RsaCtfTool

Exploit Command

python3 -c "from Crypto.PublicKey import RSA; import gmpy2; n = MODULUS; e = 65537; # Factor n"

Vulnerability Hint

1024-bit RSA is weak. Factor using yafu: yafu "factor(@)" -batchfile <(echo "MODULUS_HERE" )

Challenge Details

  • Category Real Cryptography
  • Difficulty Medium-Hard
  • CVSS Score 8.5 (High)
  • Attack Vectors 5
  • Challenge ID 4ae49ecf2e5f

Cryptographic Vulnerabilities

  • Weak RSA (1024-bit, factorable)
  • AES-ECB mode (pattern leakage)
  • CBC padding oracle (POODLE)
  • XOR key reuse (stream cipher)
  • Timing attack (strcmp vs hash_equals)
  • IV reuse in CBC mode

API Reference

GET
/crypto1/?api&action=get_challenge
GET
/crypto1/?api&action=decrypt&cipher=[base64]
GET
/crypto1/?api&action=verify&token=[token]
GET
/crypto1/?api&action=attack&type=[type]

Learning Objectives

RSA Cryptanalysis
Block Cipher Modes
Timing Attacks
Secure Implementation

Cyber Fortress CTF • Quantum Cryptography Challenge • COMP50003 Cyber Security

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Use only in controlled, authorized environments. Never test systems without explicit permission.