What is the principle of public key cryptography ? Discuss the applications for public key cryptography.

Principle of Public Key Cryptography:

Evolution from Symmetric Encryption:

• In traditional symmetric encryption, two parties share a secret key.
• The challenge arises in distributing and managing this secret key securely.

Key Distribution Center Issue:

• Using a Key Distribution Center introduces a single point of failure and compromises security.

Secrecy Challenge:

• Maintaining complete secrecy in communication becomes difficult.

Applications of Public Key Cryptography:

Encryption/Decryption:

• Easy Explanation: The sender uses the recipient’s public key to lock (encrypt) a message.
• Example: Imagine putting a message in a box with a lock that only the recipient’s key can open.

Digital Signature:

• Easy Explanation: The sender signs a message with their private key.
• Example: It’s like putting a unique seal on a letter to prove it’s from you, and only your private key can create that seal.

Key Exchange:

• Easy Explanation: Two parties work together to create a secret session key.
• Example: It’s like agreeing on a secret code during a conversation, and only the parties involved know how to use it.