From the course: Performing a Technical Security Audit and Assessment

File integrity checking tool demo

- [Instructor] To illustrate how file integrity checking works, I'll use the Hash Tool, which is a simple free file hashing utility from DigitalVolcano. I have the Hash Tool open and I'll select a file I'd like the tool to generate a hash for. You can see the Hash Tool has generated this long string of characters. This is the hash of the file's contents. We'll use this as our baseline hash. Now I'll go into the file and make a small change. I'll just delete this comma and save the file. Now I'll run a validation hash of the file and see what happens. We can see that these hashes are completely different, even though I only made a small change. Now I'll go back into the file and replace the comma. Then I'll rerun the hash. Here you can see that by replacing the comma, the hash is once again the same as the baseline, and I've restored the integrity of the file. While you may not use hash tools in exactly this way to conduct security assessments, this demo showed you the principle behind file integrity checking.

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