Abstract: A method is provided for secure transmission of a message via a network where a recipient of the message need not be a party to the network or maintain an active address in the network. Instead, new accounts are created dynamically by the system of the invention in response to a message addressed to an unknown user by sender who is a party to the network. In the operation of the method of the invention, messages from a network-party sender addressed to such an unknown user are deposited into a unique account created for the addressed recipient. That addressed recipient is notified via a non-network communication path that a message is stored and available to it at a network address, and is provided instructions for accessing that network address to retrieve its message.