This pun-based tool allows you to calculate checksums. You can either use the online service at: michaelchecksum.com or the console version.
This web service allows you to externally assert that the file served has the documented checksum, showing an nice badge as a seal of approval (which you can embed anywhere with an Internet connection).
For the extra paranoid: this does not assert 100% that when you download the same file, it will arrive on your machine with the correct checksum. (it may be altered or corrupted on the way to your machine).
Use the console application for that purpose.
A cross-platform (Linux, Mac & Windows) console application without file size restrictions can be installed from NuGet:
global:
dotnet tool install -g michaelchecksum.console
or local:
dotnet tool install --tool-path . michaelchecksum.console
For upgrading replace
install
withupdate
Calculate a SHA-1 hash using:
michaelchecksum myfile.txt # relative file
michaelchecksum c:\myfile.txt # file on a drive (Windows)
michaelchecksum /path/myfile.txt # file on a drive (Linux/Mac)
michaelchecksum https://myfile.txt # file via url
Also see the releases section for when you do not have .Net Core installed.