An Extension of the Sender Domain Authentication DKIM

The sender domain authentication protocol DKIM (domain keys identified mail) attracts much attention, in which the sender domain adds a signature header generated from headers and body of the original email, and the sender domain will be authenticated by a verification of the signature. However, a verification will be failed when headers are changed before it is reached to the receiver. This article proposes to combine DKIM and PIAT, the partial integrity assurance technology, so that the original sender domain authentication will be successful even when headers are changed by a mailing-list domain without generating a signature on the modified email.