Symmetric encryption algorithms like DES and AES are widely used to secure data

Symmetric encryption algorithms like DES and AES are widely used to secure data, but they come with key management and key exchange challenges.

Explain how symmetric encryption works, focusing on the structure of DES, including the Feistel network and the role of S-boxes.
How does AES improve upon DES in terms of security and efficiency?
In your response, also discuss the challenges of key management and key exchange in symmetric encryption systems. Why is securely exchanging keys such a critical issue, and what solutions or strategies are commonly used to address this challenge?
Peer Reply Guidance:
Respond to at least two peers with substantive paragraphs.