A system and method for sending encrypted messages to a distribution list. In one embodiment, the method comprises: identifying a distribution list address in a message; determining one or more member addresses associated with the distribution list address; for each member address, determining if a public key for a member identified by the member address is available on the computing device; and if so, encrypting the message to the member; sending the encrypted message to the distribution list address only if each of the one or more member addresses associated with the distribution list identifies a member for which a public key is available on the computing device.