Patent attributes
An apparatus configured to construct an email message addressed to a plurality of recipients. The apparatus is further configured to apply a cipher and a first encryption key to a first portion of the email message, which will be viewable by each of the recipients. The apparatus applies the cipher and a second encryption key to a second portion of the email message, which will be viewable by a first recipient from among the recipients. The apparatus further applies the cipher and a third encryption key to a third portion of the mail message, which will be viewable by a second recipient from among the recipients. The apparatus then transmits the email message to a server.