Certified Information Systems Auditor Practice Exam 2026 - Free CISA Practice Questions and Study Guide

The primary purpose of a checksum in electronic data interchange communications is to maintain data integrity. A checksum is a value derived from the contents of a data block (such as a file or a message) and is used to detect errors in data transmission. By calculating a checksum before sending data and again after receiving it, systems can determine if the data has altered in transit. If the checksums match, it indicates that the data has retained its integrity; if they do not, it suggests that errors have occurred, prompting further action such as requesting a retransmission.

While confirming data format, ensuring data retention, and verifying transaction speed are important aspects of data communications, they do not directly pertain to the role of a checksum. Data format and structure are usually addressed by protocols, while data retention pertains to storage capabilities. Transaction speed is related to the performance of the systems involved, rather than the integrity of the data itself.