Cipher encoding/decoding

Questions involving Caesar cipher, Vigenere cipher, or other encryption methods where plaintext is encoded or transmitted text is decoded.

1 questions · Easy -1.2

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OCR MEI C4 2010 January Q8
6 marks Easy -1.2
8 A passage of plaintext is encoded by using the Caesar cipher corresponding to a shift of 2 places followed by the Vigenere cipher with keyword ODE.
  1. The first letter in the plaintext passage is \(F\). Show that the first letter in the transmitted text is \(V\).
  2. The first four letters in the transmitted text are VFIU. What are the first four letters in the plaintext passage?
  3. The 800th letter in the transmitted text is \(W\). What is the 800th letter in the plaintext passage?