1. Caesar's Cipher: Description: Caesar's Cipher is a substitution cipher that shifts each letter in the plaintext by a fixed number of positions. The shift value, known as the key, determines the amount of displacement. It is a simple and historically significant encryption technique, named after Julius Caesar.

2. Columnar Cipher: Description: Columnar Cipher is a transposition cipher that rearranges the order of characters in the plaintext based on a keyword. The message is then read out column by column, providing a method of encryption where the keyword determines the arrangement of characters.

3. Rail Fence Cipher: Description: Rail Fence Cipher is a transposition cipher that arranges the characters of the plaintext in a zigzag pattern across a set number of rails or lines. The characters are then read off in rows, forming the encrypted message. The direction of the zigzag pattern (up or down) is a defining characteristic.

4. Vigenère Cipher: Description: Vigenère Cipher is a polyalphabetic substitution cipher that uses a keyword to shift the letters in the plaintext. The keyword is repeated to match the length of the plaintext. Unlike Caesar's Cipher, the Vigenère Cipher uses multiple cipher alphabets, making it more resistant to simple frequency analysis.