Caesar Shift
This is a very simple cipher where the alphabet is shifted left or right by a number of characters (offset)
e.g.
Original: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Offset 5: F G H I J K L M N O P Q R S T U V W X Y Z A B C D E
Phrase:
Nice day for a walk
Cipher:
Snhj ifd ktw f bfqp
Javascript implementation: