File Integrity Verification with Hashing using CertUtil

Initial SHA256 hash generation using CertUtil.

To demonstrate integrity checking using cryptographic hashes, I used CertUtil, a built-in Windows utility, to generate and verify SHA256 hashes on local files. This technique is vital in areas like forensics, secure backups, and malware detection, where detecting unauthorized changes is critical.

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Test Setup

testfile successfully created and placed.

I created a sample file named testfile.txt, inserted simple text, and then used CertUtil to generate its hash. Afterwards, I modified the file to simulate tampering, then restored it to demonstrate hash matching.

After creating the sample file, i made a copy, so that it can be tampered with:

Copy of testfile.txt.

Then i tested the hashes:

Identical SHA256 hash generation proven.

Afterwards, i tampered with the copied file, and tested the hashes again:

Initial SHA256 hash is now different.

I also tested SHA1 and SHA512.

Different hash algorithm visible.

This project ties directly into the Security+ Domain regarding Cryptographic Concepts.

Now, i have successfully demonstrated how:

Hashes detect changes in files.

Cryptographic integrity checks are critical for verifying file authenticity.

SHA256 is a secure hashing algorithm supported by Windows natively via certutil.

Skills demonstrated:

SHA256 hashing

Detecting file integrity violations

Using native Windows tools for secure file validation

Incident response preparation (malware detection, file baselining)

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