How about one-time electronic stamps. I generate a large-ish number of long-ish random numbers. I store these into a data base on my system. I send one e-stamp to all of the people I want to communicate with and vice versa. Each person uses the e-stamp in the header or some other area of their message to me easily accessible to my mail bot. My bot reads the e-stamp and then checks the data base to see if the stamp is valid. If not, then /dev/null. If so, then: a) send the message to me; b) delete the used e-stamp from the data base; c) send a confirmation of received message with a new e-stamp in it. Thoughts? (I see one problem with this but it should be able to be worked out once the basic method is agreed to). --tallpaul