What technology is commonly used to validate the authenticity of email messages?

The technology that is commonly used to validate the authenticity of email messages is DomainKeys Identified Mail (DKIM). DKIM works by allowing the sender to digitally sign their email messages. This signature is created using a private key that corresponds to a public key published in the sender's DNS record. When the email is received, the recipient’s server can verify the signature using this public key. This process ensures that the message has not been altered during transit and confirms that it indeed comes from the claimed sender’s domain.

This authentication method is critical in combating email forgery and phishing, as it provides a way for recipients to trust the messages they receive based on the validation provided by DKIM.

In contrast, Simple Mail Transfer Protocol (SMTP) is a protocol used for sending emails but does not inherently provide authentication. Internet Message Access Protocol (IMAP) and Post Office Protocol (POP3) are both protocols used to retrieve emails from a server but similarly do not offer any mechanisms for validating the authenticity of the messages themselves.