🔐 The Caesar Cipher

The Caesar Cipher is one of the oldest and simplest encryption techniques, named after Julius Caesar who used it to communicate with his generals.

How It Works

Each letter in the plaintext is shifted a fixed number of positions down the alphabet. For example, with a shift of 3:

• A becomes D
• B becomes E
• C becomes F
• ...and so on

Example

Plaintext: HELLO

Shift: 3

The Cipher Alphabet (Shift of 3)

Plain

A

B

C

D

E

F

G

H

I

J

K

L

M

Cipher

D

E

F

G

H

I

J

K

L

M

N

O

P

Plain

N

O

P

Q

R

S

T

U

V

W

X

Y

Z

Cipher

Q

R

S

T

U

V

W

X

Y

Z

A

B

C

How to Crack It

1. Brute Force: There are only 25 possible shifts, so try them all!
2. Frequency Analysis: In English, 'E' is the most common letter. Find the most frequent letter in the ciphertext and assume it's 'E'.
3. Pattern Recognition: Single-letter words are usually 'A' or 'I'. Common three-letter words include 'THE', 'AND', 'FOR'.

Tips

• ROT13 is a special Caesar cipher with a shift of 13
• The shift can go in either direction (left or right)
• Numbers and punctuation are usually left unchanged