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Cryptography Challenges

RSA Challenge One: RSA Small Message Space Attack

The Problem: Given an RSA ciphertext encrypting one of several messages, recover the message.

You are a government agent trying to determine when your neighboring country, Malland, will attack. You intercepted an encrypted message c from Malland to its ally, Horridland. You know that the encrypted message uses RSA, and that the Mallanders are likely to be saying one of three things:

  • "attack tomorrow at dawn",
  • "attack just before dusk", or
  • "attack early next week".

Use this knowledge to figure out what the message is.

For this exercise, use the following values:

Name Value
Modulus:
Exponent:
Ciphertext: