Which type of encryption uses the same key for both encryption and decryption?

• A. Symmetric Encryption
• B. Asymmetric Encryption
• C. Font Code (Steganography)
• D. One Time Pad

Answer: (A)

The main idea here is that symmetric encryption uses a single shared secret key to both encrypt and decrypt data. Because the same key does both jobs, it must be kept secret and securely exchanged between communicating parties, which makes the process fast and efficient for large amounts of data. This contrasts with asymmetric encryption, which uses a pair of keys (one for encryption, one for decryption) to enable public-key use and easier key distribution, but at a higher computational cost.

One-time pad is a special case where a key as long as the message is used only once; while it technically uses the same key for both steps, it’s impractical for everyday use due to key management requirements. The general category that matches the description most directly is symmetric encryption.