Advanced Placement (AP) Computer Science

Which of the following is a type of encryption?

1. Public key encryption

2. Data compression encryption

3. Information retrieval encryption

4. File encryption

The correct answer is: Public key encryption

Public key encryption is indeed a recognized type of encryption. It is a cryptographic system that uses pairs of keys: a public key, which can be shared with everyone, and a private key, which is kept secret. This enables secure communication over unsecured channels, allowing users to encrypt messages with the recipient's public key, which can only be decrypted by the recipient's private key. This method enhances security by ensuring that only the intended recipient can access the encrypted information. Public key encryption is fundamental in various applications, such as secure email, SSL/TLS for web security, and digital signatures, making it a crucial concept in the field of cybersecurity. The other choices either do not represent established forms of encryption or are incorrectly phrased in the context of encryption types. For instance, data compression does not involve encryption mechanisms, information retrieval is more concerned with how data is obtained rather than secured, and file encryption is indeed a real concept but does not encompass the broader principles like public key encryption does. Such distinctions help clarify the importance and relevance of public key encryption within the realm of secure communication.