Hello,
It would nice to have a simple checksum file checker.
You drop the file, and the checksum.
This is how I do this today.
open Terminal by searching for it in Spotlight or Launchpad, or open it directly in Applications > Utilities.
Once open, type in "shasum -a " followed by either 1 or 256, depending on whether you want to verify the downloaded file against a SHA-1 or SHA-256 checksum provided by its developer.
Next, add a space, followed by the full path to the file. (Seen above.)
For instance, we're going to check the "HandBrake-1.0.7.dmg" file, which is located in the Downloads folder, hence the path will look like this: "/Users/future/Downloads/HandBrake-1.0.7.dmg".
Alternatively (and much more easily), you can simply drag and drop the file onto Terminal's window to automatically paste the full path to it.