Image from https://www.gov.uk/government/publications/email-security-standards/domainkeys-identified-mail-dkim under Open Government Licence.
As of now, emails we send from all domains that we hold are signed with DKIM, Domain Keys Identified Mail.
We have been using SPF, Sender Policy Framework for some years. This helps prevent spoofing emails and is used to in detect spam and phishing emails. However, by using DKIM in addition to SPF it ensures our customers are getting better security. Domain Keys Identified Mail is an email authentication technique that verifies an email’s domain to help ensure that emails have not been tampered with during transit. We can then filter or reject email that fails the DKIM check.
This applies to all emails sent from email accounts and websites that we provide: just another built-in feature of our service!
Read more about Domain Keys Identified Mail from the Government Digital Service;
which provided the image under Open Government Licence.