Abstract: A system and method for providing security in data communication systems where multiple users are coupled to a common receiving system. The data is encrypted or otherwise encoded by a sender using a key. The encrypted data is then scrambled or otherwise encoded, and transmitted by the sender. The transmitted data is received at a receiver where it is descrambled or otherwise decoded. An authorized user decrypts or otherwise decodes the descrambled data using a key to retrieve clear data. The key itself is encrypted by the sender using an asymmetric encryption algorithm, and is then transmitted by the sender. The authorized user decrypts the encrypted key using the asymmetric encryption algorithm, and uses the key to decrypt the encrypted data.

Abstract: A system and method for ensuring user privacy in a messaging system where a message is sent from a sender to a recipient via a service provider. Information pertaining to the identification of a sender and recipient of a message is encrypted so that a third party cannot determine who is sending the message to whom. Specifically, delivery information of the message is reformatted to indicate that the service provider is the recipient. The identification of the actual recipient is encrypted and sent along with the message to the service provider. Upon receipt, the service provider decrypts the actual recipient information to determine the identification of the actual recipient. The service provider reformats the delivery information to indicate that the actual recipient is the recipient of the message and that the service provider is the sender of the message. The identification of the actual sender is encrypted and sent along with the message to the actual recipient.