Data Integrity: Keeping Data Accurate and Unchanged

Varonis (see Resource 2) talks about Data Integrity in this way -

Data integrity refers to the reliability and trustworthiness of data throughout its lifecycle. It can describe the state of your data—e.g., valid or invalid—or the process of ensuring and preserving the validity and accuracy of data.

Data integrity is about ensuring that stored data remains accurate, complete, and unchanged from its original state. While confidentiality focuses on keeping data private, integrity focuses on keeping data trustworthy and correct. Data should stay intact, but that isn't always the case. Files can become corrupted due to hardware failures, software bugs, transmission errors, or malicious tampering. The fundamental principle behind data integrity is simple: the data you store should be exactly the same data you retrieve later.

Verifying Data Hasn't Changed

Proving that a file is identical now to when it was originally created or sent is a fairly technical process. A cryptographic "hash" (like a unique digital fingerprint) or checksum can be calculated for a file. If even a single character in the file changes, the hash value will be completely different. By comparing the hash of the original file with the hash of the received file, you can verify with certainty that nothing has changed. This video demonstrates the method: https://www.youtube.com/watch?v=O0s8tKTL_MA. Hash verification is commonly used when downloading software or important files to ensure they haven't been tampered with during transmission.

Why Integrity Matters: Real-World Examples

Data integrity affects everyday work in ways that are easy to overlook until something goes wrong:

An Excel spreadsheet is only as useful as the data it contains and the formulas that calculate results. If values change unexpectedly or formulas become corrupted, your financial reports or business decisions could be based on incorrect information.
A Word document that has corrupted text or randomly altered content becomes unreliable. Imagine submitting a contract or report only to discover that critical details were changed without your knowledge.
If a text message to your boss has characters randomly altered during transmission, it could lead to embarrassing misunderstandings or serious miscommunication. While this sounds like autocorrect misbehaving, it's actually a failure of data integrity.

Fortunately, most modern software includes built-in integrity checking mechanisms that work behind the scenes. Email systems, file transfer protocols, and databases regularly perform integrity checks to verify that data hasn't been corrupted or tampered with. These systems will typically alert you if something fails these checks – you might see error messages like "file is corrupted" or "unable to open document."
Files that suddenly fail to open or display error messages
Spreadsheets with formulas that produce incorrect results
These symptoms shouldn't be ignored. While they might indicate ordinary hardware problems or software glitches, they could also be warning signs of a cyberattack in progress. Attackers sometimes deliberately corrupt or modify data as part of ransomware attacks, sabotage, or to cover their tracks. If you notice repeated integrity failures or suspicious changes to files, report them to your IT or security team immediately.
Data integrity works together with Confidentiality and Availability to form the foundation of CyberSecurity (often called the "CIA triad"). Confidential data that's been altered is no longer trustworthy. Available data that's been corrupted is useless. All three elements must work together to ensure that data is private, accurate, and accessible when needed.

Lesson 2 – Integrity