After completing this experiment, you will be able to:

1. Understand the Data Encryption Standard (DES)

• Explain the principles of symmetric-key encryption.
• Describe the structure and working of the DES algorithm.
• Understand the role of block size, key size and Feistel rounds in DES.

2. Perform DES Encryption and Decryption

• Encrypt plaintext using DES.
• Decrypt ciphertext using the same secret key.
• Verify the correctness of the encryption and decryption processes.

3. Understand Triple DES (3DES)

• Explain why DES became vulnerable to brute-force attacks.
• Understand how Triple DES enhances the security of DES.
• Describe the Encrypt–Decrypt–Encrypt (EDE) operation used in 3DES.

4. Analyse Cryptographic Keys

• Distinguish between the 64-bit DES key and its effective 56-bit key length.
• Understand the use of multiple keys in Triple DES.
• Compare single DES and Triple DES from a security perspective.

5. Evaluate Practical Security

• Compare DES and Triple DES in terms of security and computational cost.
• Recognize the strengths and limitations of DES in modern cryptographic applications.
• Appreciate the historical significance of DES in the evolution of symmetric-key encryption.