(ISC)2 Certified in Cybersecurity Practice Exam

What is the main function of hash functions in data integrity?

1. To store data in an encrypted format

2. To provide time-stamped records

3. To ensure data has not been altered

4. To facilitate backup processes

The correct answer is: To ensure data has not been altered

Hash functions play a critical role in ensuring data integrity by creating a unique digital fingerprint or hash value for a given set of data. This hash value is a fixed-size string that is generated through a mathematical algorithm, and even the smallest change in the original data will result in a completely different hash value. This property allows for quick verification of data integrity. When data is transmitted or stored, its hash value can be calculated and compared to a previously generated hash value. If the two hash values match, this confirms that the data has not been altered or tampered with. If there’s any discrepancy between the hash values, it indicates that the data may have been modified in some way, alerting stakeholders to potential integrity issues. Through this mechanism, hash functions are pivotal for various applications, such as validating file downloads, ensuring the integrity of messages during transmission, and maintaining secure digital signatures. Their primary purpose aligns perfectly with the need to ensure that data remains unchanged from its original state during its lifecycle. The other options, while important in their own right, do not directly relate to the fundamental role of hash functions in maintaining data integrity. Storing data in an encrypted format is related to confidentiality, providing time-stamped records deals with tracking events over time, and