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Symmetric-key·medium·35 pts
A Longer Key Isn't Always Enough
This time the XOR key repeats instead of being a single byte. Does that actually help?
A junior developer heard single-byte XOR was weak, so they "fixed" it by using a short repeating key instead — cycling through several key bytes rather than just one.
The flag's fixed cct{ prefix is exactly as dangerous here as it was against a single byte.
Ciphertext (hex)
28262d21397629692a3168342c1a216a391a6829257206373e26310529762d2e7837062e237137057b2b6a05293c2d6936
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Background on this technique
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Reused Keystream →Two messages, encrypted under what should have been two different one-time keys.