정답: D
Key management is the process of generating, distributing, storing, using, and destroying cryptographic keys. One of the most significant key management problems is the number of keys created, which affects the complexity, scalability, and security of the cryptographic system. The number of keys created depends on the type of encryption used: symmetric or asymmetric.
Symmetric encryption uses the same key for encryption and decryption, while asymmetric encryption uses a pair of keys: a public key for encryption and a private key for decryption. When using symmetric encryption, the number of keys created grows exponentially with the number of users or devices involved. For example, if there are n users or devices that need to communicate securely with each other, then each user or device needs to have a unique key for each other user or device. Therefore, the total number of keys needed is n(n-1)/2, which is an exponential function of n. This means that as the number of users or devices increases, the number of keys needed increases dramatically, making it more difficult to provision, store, and protect the keys.
When using asymmetric encryption, the number of keys created grows linearly with the number of users or devices involved. For example, if there are n users or devices that need to communicate securely with each other, then each user or device needs to have only one pair of keys: a public key and a private key. Therefore, the total number of keys needed is 2n, which is a linear function of n. This means that as the number of users or devices increases, the number of keys needed increases proportionally, making it easier to provision, store, and protect the keys.
