Скачать или смотреть How to Output SHA1, SHA256, and File Signature Status Using PowerShell

Learn how to efficiently compute and output file hashes (MD5, SHA1, SHA256) and their signature status using PowerShell with this step-by-step guide.
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This video is based on the question https://stackoverflow.com/q/63534572/ asked by the user 'Hakdicap' ( https://stackoverflow.com/u/13830102/ ) and on the answer https://stackoverflow.com/a/63535087/ provided by the user 'Theo' ( https://stackoverflow.com/u/9898643/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

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Introduction

If you've been working with files in PowerShell, you might find yourself needing to compute file hashes and check their signature status. Perhaps you want to monitor integrity or validate the authenticity of different files without running extensive manual checks. In this post, we will address a common query: How can we add SHA1 and SHA256 calculations to a PowerShell command while also checking if the files are signed or unsigned?

Let’s dive into a step-by-step solution that’s efficient and insightful!

The Challenge

A user was attempting to modify a PowerShell command that originally calculated MD5 hashes to also include SHA1 and SHA256 hashes, along with the ability to check file signatures. Here is the original command they were using:

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This command effectively followed the process to calculate MD5 hashes for all files under the C:\ drive but lacked the capability to extend that functionality to SHA1, SHA256, and file signature checks.

Proposed Solution

The user needs a method to calculate all three hash types efficiently while also checking if the file is signed. Instead of reading each file multiple times (once for each hash), we can read each file as a byte array just once. Below is a structured solution to achieve our goal:

Step 1: Setup the Hasher Objects

We will need to create hasher objects for MD5, SHA1, and SHA256. These objects will facilitate the hash calculations.

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Step 2: Loop Through Files

Use Get-ChildItem to loop through the files in the desired path. In this case, I've suggested reading files from a specific folder like C:\SomePath rather than the entire C:\ drive to avoid long execution times.

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Step 3: Exporting Results

Finally, export the results to a CSV file. This step ensures that you can view the hash values and signature status in a structured format.

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Step 4: Cleanup

After the hashing process is complete, it’s good practice to dispose of the hasher objects.

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Conclusion

By following the structure above, you can efficiently compute MD5, SHA1, and SHA256 hashes, and check if the files are signed or unsigned, all while minimizing file access time. This method is optimal for processing many files with minimal delays.

Remember to adapt the path in the script to fit your exact requirements, and consider running the operation on smaller batches of files to manage performance effectively.

Start utilizing this approach today, and enhance your file handling capabilities in PowerShell!