What is CheckSum?
An MD5 checksum is a mathematical algorithm is usually a set of 32-character hexadecimal letters and numbers that are computed on a file with a tool. These numbers are generated using special tools that employ “cryptographic hash function producing a 128-bit (16-byte) hash value”. It is used not only to encrypt a ZIP archive or an EXE installer but all kinds of files. You can assign an MD5 sum even to a text or document file. The perfect match of MD5 checksum value ensures that the digital integrity and security of a file has not been broken by someone else and also that it is the accurate copy of the original file.
Thus, there are the two main reasons if the MD5 hash value of a file you downloaded does not match against the original sum:
The file might be modified by someone else in an unauthorized way.
The file was not downloaded properly and some of its elements might have been corrupted.
How does CheckSum work?
A file is pushed through an algorithm, which outputs a unique alphanumeric string called a checksum, also known as a "hash". Different files, even those with minute differences, produce different checksum values.
There are multiple algorithms that can be used to produce a checksum value. The algorithm can be MD5, SHA-1, SHA-256, and SHA-512, etc.
How to calculate the CheckSum of a file (Windows)
Option1:
- Open Windows Powershell from the Windows menu.
- Get-FileHash <filepath> -Algorithm MD5. Example can be:
Get-FileHash "C:\Users\bww\Downloads\Qlik Alerting Installer (2).exe" -Algorithm MD5
3. Press Enter
Option2:
- Download the latest version of WinMD5Free.
- Extract the downloaded zip and launch the WinMD5.exe file.
- Click on the Browse button, navigate to the file that you want to check and select it.
- Just as you select the file, the tool will show you its MD5 checksum.
- Copy and paste the original MD5 value provided by the developer or the download page.
- Click on Verify button.
