Patent ID: 8151112

Claim:
A method of selectively collecting an electronic mail message from a source message server computer to a destination message client computer, the method comprising the steps of: providing the electronic mail message by a source message client computer, used by a sender who has an electronic mail message account administrated by the source message server computer; detaining the electronic mail message at the source message server computer; sending an intend-to-deliver containing identification parameters of the electronic mail message by the source message server computer to a destination message server computer, the intend-to-deliver being further processed by the destination message server computer administrating an electronic mail message account for a recipient using the destination message client computer; providing a first public key of public key cryptography from the destination message server computer to the source message server computer upon receipt of the intend-to-deliver; processing the intend-to-deliver by the destination message server computer; providing the processed intend-to-deliver by the destination message server computer to the destination message client computer without the intend-to-deliver being directly opened by the destination message client computer; responding to the processed intend-to-deliver with a request-for-mail-content containing identification parameters and an authentication information which is a series of data codes including instructions of providing the detained electronic mail message, the authentication information being encrypted with a secret key associated with the first public key for the recipient's electronic mail message account, the request-for-mail-content being sent from the destination message client computer to the source message server computer if the recipient accepts the detained electronic mail message; decrypting the encrypted authentication information with a second public key defined by a member of the group consisting of the first public key provided by the destination message server computer and a third public key provided by a source that the source message server computer considers to be trustworthy, the source message server computer decrypting the encrypted authentication information upon receipt of the request-for-mail-content; and responding to the request-for-mail-content based on the instructions for providing the detained electronic mail message by the source message server computer if and only if the encrypted authentication information is successfully decrypted.