SML is a secure mailing list. It is designed from the ground up to provide a secure mailing agent for groups of people who want to communicate with some confidence that only those subscribed to the list will be able to read the messages passing through it, and that no one will be able to get on the list without the consent of current list members.
SML is being designed to be scalable. Since the encryption and decryption of mail messages is an intensive task, SML is built to ensure it can not only handle a large volume of mail, but also that it won't overload the server it is running on.
SML provides several levels of security, from non-encrypted, but validated using digital signitures, to fully encrypted, to a full anonymous e-mail list. SML also provides a mechanism of "trust metrics" so that list members can decide what information sent over the list can be trusted.