Third-party e-mail authentication service provider using checksum and unknown pad characters with removal of quotation indents

Abstract

Electronic mail (email) is certified and authenticated by an authentication service. The authentication service is integrated with an email web site that allows users to set up email accounts. Outgoing email from the email web site is routed to the authentication service. A message identifier (ID) is generated and added to the message within markers. A random-number generator creates random pad characters that are added to the message before a checksum is generated. The checksum and the pad characters are stored in a table indexed by the message ID. The pad characters and the checksum are placed in secure storage and not available to users or others on the Internet. The email with the message ID in the markers but without the pad characters or checksum is sent to the recipients, along with instructions on how to authenticate the message. Others can authenticate a message by emailing it to the authentication service. The message ID is extracted from the markers and used to find the checksum and pad characters in the table. The pad characters are again added to the message and a new checksum generated. Authentication fails when the checksums do not match. An authentication-result message is added to the message before it is returned. Quotation indent characters are stripped from the message before authentication so that quoted messages can be authenticated even though they are altered by reply software during quotation. Headers such as addresses and dates can be copied to the message body so that they are also authenticated.