What characterizes the Atbash cipher?

The Atbash cipher is characterized as a substitution cipher that uses a reversed alphabet. This means that each letter in the plaintext is replaced with its corresponding letter from the opposite end of the alphabet. For example, 'A' would become 'Z', 'B' would turn into 'Y', and so forth, continuing this pattern throughout the entire alphabet.

This unique reversal creates a straightforward method for encoding messages, where the transformation is consistent and predictable, leading to a simple but effective form of cryptography. The Atbash cipher does not involve any complex mathematical processes or symbols; it relies solely on the relationship of letters in the alphabet. The operation is entirely based on their positions: the first letter is swapped with the last, the second with the second to last, and so on. This simplicity is part of what makes it a fascinating example of early cryptographic methods.