(ISC)2 Certified in Cybersecurity Practice Exam

What does ciphertext refer to in information security?

1. A clear and readable message

2. A type of computer virus

3. An encrypted message

4. A method for data backup

The correct answer is: An encrypted message

Ciphertext refers to data that has been transformed through an encryption process, making it unreadable to anyone who does not possess the appropriate decryption key or method. This transformation ensures the confidentiality and security of the information contained within the original plaintext message. The primary purpose of ciphertext is to protect sensitive information from unauthorized access, ensuring that even if an adversary intercepts the data, they cannot make sense of it without the proper credentials to decrypt it back to its original form. In contrast, a clear and readable message corresponds to plaintext, which is the opposite of ciphertext. The mention of a type of computer virus does not relate to the concept of ciphertext, as it pertains to malicious software designed to harm or exploit devices or networks. Similarly, a method for data backup is not relevant since it involves the preservation of data rather than its transformation through encryption. Understanding the distinction between plaintext and ciphertext is crucial for anyone studying information security, as it lays the groundwork for grasping broader concepts such as cryptographic processes and secure communication protocols.