Kinoco Hacker Hands-on security practice
All challenges In progress
Cryptography Level 2 70 points

One-Time Pad Key Reuse Attack

Mission

A one-time pad is safe only when the key is used once. Reusing the key lets known plaintext recover other plaintexts. Two ciphertexts encrypted with the same key: ciphertext1_hex = 1c0a070901 known_plaintext1 = HELLO ciphertext2_hex = 060a1e160b Recover the key from known_plaintext1 and ciphertext1, then XOR-decrypt ciphertext2. Wrap the recovered string in KINOCO{...} to form the flag.

#cryptography#otp#xor#key-reuse

Clear it in 3 steps

Not started

  1. No environment needed

    This challenge can be solved with the information in the statement alone. Submit the flag you find directly.

  2. Submit the flag