Which encryption scheme uses two different keys for encryption and decryption?

Which encryption scheme uses two different keys for encryption and decryption?

• A. Symmetric encryption
• B. Asymmetric encryption
• C. Hashing
• D. Symmetric Key Exchange

Answer: (B)

Two different keys for encryption and decryption describe asymmetric encryption. In this setup, a public key is used to encrypt messages and a separate private key is used to decrypt them, so the key that encrypts is not the same as the key that decrypts. This allows secure communication without sharing a secret key in advance. The other options don’t fit this idea. Symmetric encryption uses the same secret key for both locking and unlocking, requiring the key to be shared securely beforehand. Hashing isn’t encryption at all—it’s a one-way function that creates a fixed digest and isn’t reversible to recover the original data. “Symmetric Key Exchange” isn’t the standard term for a two-key system and would still imply sharing a single key rather than two distinct keys for encryption and decryption.

Two different keys for encryption and decryption describe asymmetric encryption. In this setup, a public key is used to encrypt messages and a separate private key is used to decrypt them, so the key that encrypts is not the same as the key that decrypts. This allows secure communication without sharing a secret key in advance.

The other options don’t fit this idea. Symmetric encryption uses the same secret key for both locking and unlocking, requiring the key to be shared securely beforehand. Hashing isn’t encryption at all—it’s a one-way function that creates a fixed digest and isn’t reversible to recover the original data. “Symmetric Key Exchange” isn’t the standard term for a two-key system and would still imply sharing a single key rather than two distinct keys for encryption and decryption.