What they are and why they’re useful
A checksum is a short list of characters that we derive from the content of a release’s .zip file.
If you have the checksum of a release file you can check that your downloaded copy is identical to ours.
Where to find them
For each release there is a link to download the release checksum file next to the link to download the release file itself.
The checksum file is an XML document containing the information needed to check the release file.
How to use them
The checksum file is used with the File Checksum Integrity Verifier (FCIV) software available from Microsoft Corporation.
Instructions for downloading and installing FCIV can be found on the Availability and description of the File Checksum Integrity Verifier utility page.
Let’s assume that you’ve installed FCIV and you’ve downloaded a release and its checksum file. Our example uses a release file named nhsbsa_dmd_1.0.0_20180101000001.zip and a checksum file named trud_nhsbsa_dmd_1.0.0_20180101000001.xml.
To check the release follow these steps:
- Copy the files to the directory where FCIV is installed.
- Open a Command Prompt. Press the Win + R keys on your keyboard, then type cmd in the Open box and press Enter.
- Change to the directory where FCIV is installed.
fciv -v -sha1 -xml trud_nhsbsa_dmd_1.0.0_20180101000001.xml
and press Enter.
If your copy of the release file is identical to ours you’ll see something like this:
// File Checksum Integrity Verifier version 2.05.
Could not create the registry key.
Starting checksums verification : 01/07/2018 at 13h26'52
All files verified successfully
End Verification : 01/07/2018 at 13h26'52