Our mail servers are configured to use DKIM in order to verify the identity of our emails. If you receive an email from our domain which is not signed then you should ignore it.
DomainKeys Identified Mail (DKIM) lets an organization take responsibility for a message that is in transit. The organisation is a handler of the message, either as its originator or as an intermediary. Their reputation is the basis for evaluating whether to trust the message for further handling, such as delivery. Technically DKIM provides a method for validating a domain name identity that is associated with a message through cryptographic authentication.