1. Caesar Cipher
Definition:
In a Caesar cipher, each letter in the plaintext is shifted a fixed number of places down the alphabet.
Example (Shift = 3):
-
Plaintext:
HELLO -
Ciphertext:
KHOOR -
H → K
-
E → H
-
L → O
-
L → O
-
O → R
Merits:
-
Simple to implement and understand.
-
Requires minimal computational resources.
Demerits:
-
Easily broken using frequency analysis or brute-force (only 25 possible shifts).
-
Not secure for modern communication.