Atbash Cipher

The Atbash cipher is an encryption method in which each letter of a word is replaced with its "mirror" letter in the alphabet: A <=> Z; B <=> Y; C <=> X; etc.

Create a function that takes a string and applies the Atbash cipher to it.

Examples

atbash("apple") ➞ "zkkov"

atbash("Hello world!") ➞ "Svool dliow!"

atbash("Christmas is the 25th of December") ➞ "Xsirhgnzh rh gsv 25gs lu Wvxvnyvi"

Notes

• Capitalisation should be retained.
• Non-alphabetic characters should not be altered.