Cisco Certified Network Associate (CCNA) Practice Exam

What type of cryptography uses a single key for both encryption and decryption?

1. Asymmetric Key Cryptography

2. Symmetric Key Cryptography

3. Public Key Infrastructure

4. Hash Function

The correct answer is: Symmetric Key Cryptography

The type of cryptography that uses a single key for both encryption and decryption is symmetric key cryptography. In this method, the same secret key is employed to encrypt messages and to decrypt them, which means both the sender and the recipient must securely share and maintain the confidentiality of this key. Symmetric key cryptography is efficient for handling large amounts of data and is widely used in various applications, such as securing communications, data storage, and file encryption. The simplicity of using one key helps streamline the encryption and decryption processes. In contrast, asymmetric key cryptography uses two distinct keys: a public key for encryption and a private key for decryption. Public key infrastructure relies on a system of digital certificates to manage keys in this asymmetric approach. A hash function, on the other hand, generates a fixed-size string of characters from input data but is not used for encryption or decryption in the traditional sense.