Which of the following is an example of a simple encoding method?

The Caesar cipher is considered a simple encoding method due to its straightforward approach to encryption. It operates by shifting each letter in the plaintext by a fixed number of places down or up the alphabet. For example, if the shift is three, then 'A' becomes 'D', 'B' becomes 'E', and so on. This simplicity makes it easy to understand and apply, which is why it's often one of the first ciphers introduced in cryptography education.

In contrast, while the substitution cipher also involves replacing letters, it can use various complex mappings instead of a uniform shift, making it less simple than the Caesar cipher. The transposition cipher changes the arrangement of characters rather than substituting them, which adds complexity in understanding how the original message is encoded. The Vigenère cipher is even more complicated, as it uses a keyword to determine the shifting of letters, requiring a more intricate approach for both encoding and decoding.

The Caesar cipher's elegance lies in its ease of use and clarity, making it a prime example of a simple encoding method.