Symmetric Ciphers

The most important tool for communication now-a-days is encryption.

There are 2 forms of encryption methods :

1. Conventional, or Symmetric encryption.

2. Public-Key, or Asymmetric encryption.


Symmetric Encryption:

Symmetric encryption is a form of cryptosystem in which encryption and decryption are performed using the same key. It is also know as conventional encryption.

This method transforms plain text into ciphertext using a secret key and an encryption algorithm. Using the same key and decryption algorithm, the plain text is recovered from the cipher text.

This is a traditional form which use substitution or transposition techniques. Substitution techniques map plain text elements into ciphertext elements. Transposition techniques systematically transpose the position of plaintext elements.

Egs:

1. Substitution Techniques.

• Caesar Cipher
• Monoalphabetic Ciphers
• Playfair Cipher
• One -Time Pad

2. Transposition Techniques.

3. Rotor Machines.

4. Steganography.