DKIM, or DomainKeys Identified Mail, is an email authentication method designed to detect forged sender addresses in emails. It allows the sender to attach a digital signature to their emails, which is verified by the receiving server using a public key published in the DNS records of the sender's domain. This helps ensure that the email is indeed from the claimed sender and has not been altered in transit. Implementing DKIM can improve email deliverability, protect against phishing attacks, and enhance the overall security of email communications.