A protocol is described which allows to send and receive messages anonymously using an arbitrary communication network, and it is proved to be unconditionally secure. This improves a result by DAVID CHAUM: The DC-net guarantees the same, but on the assumption of a reliable broadcast network. Since unconditionally secure Byzantine Agreement cannot be achieved, such a reliable broadcast network cannot be realized by algorithmic means. The solution proposed here, the DC + -net, uses the DC-net,

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... replaces the reliable broadcast network by a fail-stop one. By choosing the keys necessary for the DC-net dependently on the previously broadcast messages, the fail-stop broadcast can be achieved unconditionally secure and without increasing the complexity of the DC-net significantly, using an arbitrary communication network.