Challenges → Cryptography

Broadcast Blunder

Hard 600 pts 🚩 71 solves ⏱ Avg. time to solve: 7d 4h

Challenge Question

The same message was sent to three different recipients, each with their own RSA key. Every key used the same very small public exponent, and nobody thought about what that means when the plaintext is identical. Combine what the three ciphertexts give away and recover the message without ever needing a private key.
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Details

  • CategoryCryptography
  • Authortark
  • AddedNov 6, 2026
  • Avg. Time to Solve7d 4h
  • First Blood🩸 cyb3rPh03n1x

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