US Patent 8966621 Out-of-band authentication of e-mail messages

Technologies are described herein for providing out-of-band authentication of an e-mail message. A recipient of an e-mail message purporting to be from an organization forwards the e-mail message or submits its content to that organization for authentication. The authenticity of the e-mail message is determined based on authentication data, such as outgoing message logs or authentication keys, maintained at the source of the e-mail message. Upon authenticating the e-mail message, the recipient is informed of the authenticity of the e-mail message.