In the context of key management, which is a use of public-key encryption?

• A. To store passwords securely
• B. To create a backup of encryption keys
• C. To distribute secret keys securely
• D. To scan for malware

Answer: (C)

Public-key encryption is a crucial aspect of key management, particularly in the secure distribution of secret keys. This method leverages a pair of keys: a public key, which can be shared openly, and a private key, known only to the owner. When secret keys need to be distributed between parties, public-key encryption allows the sender to encrypt the secret key using the recipient's public key, ensuring that only the intended recipient can decrypt the message with their private key. This mechanism enhances security during transmission, preventing unauthorized access during the key exchange.

In contrast, the other options do not appropriately align with the primary function of public-key encryption. Storing passwords securely typically involves hashing rather than encryption. Creating a backup of encryption keys is usually performed using symmetric encryption or secure storage methods rather than public-key encryption. Scanning for malware is a distinct security process unrelated to key management. Thus, the distribution of secret keys securely using public-key encryption is clearly a fitting application of this technology.