Let’s peel back the layers on DES encryption—once a top-tier security method in computing.

🧠 What Is DES?

DES (Data Encryption Standard) is a symmetric-key algorithm that encrypts and decrypts data using the same key. It was developed in the 1970s by IBM and later adopted as a federal standard by the U.S. government.

⚙️ Key Features

• Block Size: DES works with 64-bit blocks of data.
• Key Length: It uses a 56-bit key for encryption (although it accepts 64-bit input, 8 bits are used for parity).
• Rounds: The encryption process consists of 16 rounds of permutation and substitution operations.

🔄 How It Works (Simplified Steps)

1. Initial Permutation (IP): Data is shuffled using a fixed pattern.
2. Rounds (16 total):
   • Each round uses a different round key derived from the original key.
   • Operations include expansion, substitution using S-boxes, permutation, and XORing with the key.
3. Final Permutation (IP⁻¹): The data is reshuffled again to produce the final ciphertext.

🔐 Why DES Was Important

• Introduced structured, secure methods for encrypting digital data.
• Used in ATM encryption, secure communications, and early digital infrastructure.
• Led to development of newer and more secure algorithms like Triple DES and AES.

❌ Why It’s Considered Weak Today

• Key Length: 56-bit keys are vulnerable to brute-force attacks with modern computing power.
• Outdated: By the late 1990s, DES was largely replaced due to increasing security demands.