How To Verify a SHA1 Checksum on OS X

Its so simple you'd be silly not to...

Download the file to somewhere close to hand such as the Desktop or Downloads folder

Open a Terminal from Applications->Utilities->Terminal.app

In the terminal enter the path to the sha1 command:

/usr/bin/openssl sha1

Enter an extra space at the end of the command - Don't press Enter yet!

now drag the downloaded file from wherever you stored it into the terminal window and OS X will kindly enter the path to the file for you - nice :)

Now press enter and the sha1 program will generate the sha1 checksum.

Compare the output from sha1 with the checksum on the download site - as long as they match you can be confident the file is authentic. If not send it to the trashcan!