DomainKeys Identified Mail, or DKIM, is a system for confirming the legitimacy of an email message using an e-signature. When DomainKeys Identified Mail is activated for a particular domain name, a public cryptographic key is published to the global Domain Name System and a private one is kept on the email server. When a new email message is sent, a signature is issued using the private key and when the email message is received, the signature is validated by the incoming POP3/IMAP email server using the public key. Thus, the receiver can easily know if the message is legitimate or if the sender’s address has been forged. A discrepancy will occur if the content of the email message has been modified in the meantime as well, so DKIM can also be used to make sure that the sent and the received emails are identical and that nothing has been added or erased. This authentication system will strengthen your email safety, since you can confirm the genuineness of the important email messages that you get and your colleagues can do the same with the messages that you send them. Depending on the particular email service provider’s adopted policy, an email that fails to pass the test may be deleted or may reach the receiver’s inbox with a warning symbol.