Camellia is a modern encryption algorithm that blends strong security with high performance—like the cryptographic equivalent of a sleek sports car with armor plating. Let’s unpack it:

🧠 What Is Camellia?

Camellia is a symmetric-key block cipher developed in 2000 by Mitsubishi Electric and NTT of Japan. It’s designed to be comparable to AES in terms of security and speed, and it’s approved by international standards like ISO/IEC, NESSIE (EU), and CRYPTREC (Japan).

⚙️ Key Features

• Block Size: 128 bits
• Key Sizes: 128, 192, or 256 bits
• Rounds:
  • 18 rounds for 128-bit keys
  • 24 rounds for 192- or 256-bit keys
• Structure: Feistel network with additional layers for diffusion and transformation

🔄 How It Works (Simplified)

1. Key Expansion: The secret key is transformed into multiple subkeys.
2. Rounds of Encryption:
   • Uses F-functions for mixing data with subkeys
   • Every six rounds, applies a special transformation called the FL-function
   • Includes S-boxes, affine transformations, and key whitening for added security
3. Final Output: After all rounds, the data is scrambled into ciphertext

🛡️ Why Camellia Is Respected

• Security: No known practical attacks; even the 128-bit version is considered safe against brute-force attacks
• Performance: Optimized for both software and hardware—from smart cards to high-speed networks
• Flexibility: Works well across different platforms and applications

🌐 Where It’s Used

• TLS (Transport Layer Security)
• Secure communications in government and enterprise systems
• Embedded devices and smart cards