A Level Computer Science OCR Practice Exam

How does asymmetric encryption differ from symmetric encryption?

1. It uses the same key for both processes

2. It doesn't use keys at all

3. It involves different keys for encryption and decryption

4. It is used exclusively for data compression

The correct answer is: It involves different keys for encryption and decryption

Asymmetric encryption is characterized by the use of different keys for the encryption and decryption processes, which is the fundamental aspect that distinguishes it from symmetric encryption. In asymmetric encryption, a pair of keys is utilized: a public key, which is used to encrypt data, and a private key, which is used to decrypt it. This approach enhances security, as the public key can be freely distributed while the private key remains confidential with the owner. In contrast to this, symmetric encryption relies on a single shared key for both the encryption and decryption processes, meaning that the same key must be used securely between both parties. The other concepts reflected in the options highlight variations from the principles of asymmetric encryption: using the same key underscores the nature of symmetric encryption, the idea of not using keys at all misrepresents both encryption methods, and the exclusive association with data compression does not indicate the function of asymmetric encryption in secure communication. Therefore, the aspect of involving different keys is the correct distinguishing feature for asymmetric encryption.