Authentication of email servers

Abstract

An originating email server is authenticated by a destination email server using a public key provided by the originating email server, thereby making it possible to detect an email with a forged origination address with no action required by a domain owner. A personal computer is authenticated using a reputation report associated with a unique number corresponding to the personal computer, enabling, in one embodiment, spam detection, and, in another embodiment, a decision that a valid user is requesting service registration at a website.

What is claimed is: 
     
         1 . A method for enabling authentication of an originating email server associated with an email, comprising:
 in a set-up phase:
 generating, by the originating mail server, a public key and a private key, and 
 refraining from distributing any of the public and private keys outside of the originating mail server; and 
   in an operational phase:
 obtaining an email ready to be sent, 
 generating, by the originating mail server, a hash for the received email, 
 encrypting, by the originating mail server, the hash with the private key to generate a digital signature, 
 prepending, by the originating mail server, the digital signature to the email, 
 sending, by the originating mail server, the prepended email to a recipient, 
 receiving, by the originating mail server, a request for the corresponding public key from a destination mail server associated with the recipient, and 
 providing, from the originating mail server to the destination mail server, the corresponding public key generated by the originating mail server. 
   
     
     
         2 . The method of  claim 1 , wherein the originating mail server uses the private key to digitally sign each outgoing email. 
     
     
         3 . The method of  claim 1 , wherein the prepending occurs without regard to an identity of an author of the email. 
     
     
         4 . A method for authentication of an originating mail server associated with an email, comprising:
 receiving an email at a destination mail server,   extracting, by the destination mail server, identification of the originating mail server and a digital signature from the received email, the digital signature having been encrypted with a private key, the private key and a corresponding public key having been generated by the originating mail server during a set-up phase in which the private and public keys are undistributed from the originating mail server,   requesting, by the destination mail server, the corresponding public key from the extracted identified originating mail server,   receiving, by the destination mail server, the corresponding public key from the extracted originating mail server,   decrypting, by the destination mail server, the digital signature with the corresponding public key received from the extracted originating mail server to yield a decrypted hash,   generating, by the destination mail server, a generated hash for the received email,   comparing, by the destination mail server, the decrypted hash with the generated hash to detect a match, and   when a match is detected, determining by the destination mail server, that the identified originating mail server extracted from the received email is authenticated.   
     
     
         5 . The method of  claim 4 , wherein the originating mail server uses the private key to digitally sign each outgoing email. 
     
     
         6 . The method of  claim 4 , further comprising delivering the authenticated email to a recipient named in the email. 
     
     
         7 . The method of  claim 4 , wherein the email is received from an intermediate mail server different than the originating mail server.