Kinoco Hacker Hands-on security practice
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Cryptography Level 4 140 points

Cryptanalysis - DSA Nonce Reuse Key Recovery

Mission

signatures.json contains two DSA signatures that reused the same nonce. Recover nonce k and private key x from the signature difference, then decrypt the flag using repeated SHA256(str(x)) as an XOR key.

#cryptography#dsa#nonce-reuse#key-recovery

Clear it in 3 steps

Not started

  1. Start the environment

  2. Investigate the target

    Available after the environment starts

  3. Submit the flag