A Review of Three Checksum Verifier Tools

What is a CheckSum?

A checksum is a unique string that identifies a file. You can think of it as a file’s fingerprint.

Why do I need a Checksum Verifier?

I have been writing scripts that automatically download programs and install them on computers. It is not secure to just download the file and blindly install it. Hackers can intercept your request and return a file that looks like what you want to install. This “spoofed” file could be a virus or some other malicious program.

This is where checksums are useful. When a file is downloaded by the script, it verifies the file is genuine by comparing its checksum to an expected checksum. If the checksums (or fingerprint) match then the program is installed on the computer.

Here are a few tools that I found on finding the right checksum verifier tool for me. The tool I like the most is the MD5 & SHA Checksum Utility

PowerShell File Checksum Integrity Verifier Pros Written in Powershell sono external programs are installed You can calculate more than one file at a time Cons Setting up this script to run is not super intuitive You cannot calculatechecksums for very large files, like an ISO for windows 10 for example. Example usage

To get the checksum of files in a folder do the following

cd C:\PsFCIV_2.5 . .\PsFCIV_2.5.ps1 Start-PsFCIV -Path C:\Sandbox\VC -HashAlgorithm SHA256 -Online

Then you will get something that looks like this:

Online Text and File Checksum Verifier Pros Really easy to use Gives you checksums calculatesusing a wide range of algorithms Cons You have to upload your files to a remote server There is a file size limit of 5MB Example Usage Select a file you want to calculate the checksum Click Calculate Checksum Scroll down to seeChecksums

Desktop tool MD5 & SHA Checksum Utility Pros Really easy to use calculates checksums using a wide range of algorithms No installer, it is a stand alone exe Handles large files such as Operating System ISOs Cons

none

Example Usage Click the Browse button and select a file Wait a minute for Checksums Either click the Copy XXX button next to the checksum or select the checksum and price ctrl+c