Caesar Cipher

Also called Shift Cipher.

Method

A Caesar Cipher will shift the alphabet $n$ times. For example,

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  
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 A

is a shift of $n=1$. Thus,

ZOOLOGY -> APPMPHZ

Complexity

Since the shift is circular with period $26$, there are only $26$ possible shifts (including the identity, the $0$ shift). Let $n=30$. Then we are shifting only $30\mathrm{mod}26\equiv 4$ times.

Example 1

Using a shift of $3$, encrypt

Meet at La Jolla Shores

This becomes

MEETATLAJOLLASHORES
PHHWDWODMROODVKRUHV