If you're downloading the ISO of Windows 10 anniversary edition (A.K.A. version 1607) then here is the file hash / checksum to verify that you have the right thing. I downloaded it from the Microsoft website today and you can also get a Windows 10 ISO using the media creation tool, which apparently just let's you select your version, and then downloads it for you. The following applies to the "English International" version, which is fancy-speak for British English.
jeff@linux:~/Downloads> sha256sum Win10_1607_SingleLang_EnglishInternational_x64.iso
jeff@linux:~/Downloads> md5sum Win10_1607_SingleLang_EnglishInternational_x64.iso
If you're on Linux then Microsoft allows a direct download of an ISO file, instead of nagging you to install the Media Creation Tool (a tool which I consider to be nonsense)