What is encryption? Differentiate between symmetric encryption and public-key encryption.

Encryption is the process of converting plaintext or readable data into ciphertext or scrambled data using cryptographic algorithms and keys. It ensures data confidentiality by making it unreadable to unauthorized users, thus protecting sensitive information from interception or unauthorized access.

Symmetric encryption uses a single shared key for both encryption and decryption. It is fast and efficient for encrypting large amounts of data but requires securely sharing the key between communicating parties.

Public-key encryption, also known as asymmetric encryption, uses a pair of keys: a public key for encryption and a private key for decryption. The public key can be freely distributed, while the private key is kept secret. Public-key encryption provides secure communication without the need to share keys in advance, enabling secure data exchange over insecure channels.

In summary, symmetric encryption uses a single shared key, while public-key encryption uses a pair of keys for encryption and decryption.