When you download a file from the internet, it may become corrupt during the download or for any other reason. But you can verify the integrity of a file using its file hashes. You can calculate the hashes of files and then compare them with the hashes provided by the download website and if they match then you know the files are identical and no tampering of any kind has occurred.
A file hash is a unique value calculated from the contents of a file using a special algorithm. There are many different file hashing algorithms available such as CRC32, MD5, SHA1, SHA256, SHA384, SHA512. The hashes calculated using different algorithms are different. Microsoft Windows operating system does not offer any native in-built tools to calculate the hashes of files. If you want a third-party file hashing tool then you can use free HashTools.
HashTools is a free program that calculates the hashes of given files. It is available both in form of an installer as well as in portable format. It supports various types of hashes such as CRC32, MD5, SHA1, SHA256, SHA384 and SHA512. Out of these CRC32 and MD5 hashes are considered weak.
In order to calculate the hashes, you have to first add the files to the HashTools. You can also add a folder and it will add all the files inside that folder to HashTools interface. After that you can click on the type of hashing algorithm and it will quickly calculate the file hashes for all the files. If the files is really large (more than 1 GB) then it might take some time but it all depends on how powerful your system hardware is.
All the hashes can be copied to the clipboard or saved in form of SFV file format. From the options for HashTools, you can toggle the setting for system integration which adds HashTools in the context menu of Windows Explorer.
You can download HashTools from https://www.binaryfortress.com/HashTools/Download/.