Militia Alert Systems Uses of alert systems Every militia unit will need an alert system. It can take many forms, depending on local circumstances. The oldest and simplest is to send out heralds or criers, who go from house to house and from neighborhood to neighborhood, raising a "hue and cry", sounding some alert device like a bell or horn to get people's attention, announcing the message in a loud voice, and perhaps posting the message on public bulletin boards. Today that would probably be done using the horn or siren of a motor vehicle and an electronic public address system. For compact neighborhoods, the alert system may consist of some kind of siren that can be heard throughout the area, which is understood by the residents to be a call to meet in some pre-arranged place to get further instructions, or to tune in to some local public notice system. For less compact situations, the militia will want to set up and periodically test an electronic alert system, probably using the public telephone system, but perhaps also or instead using wireless communications, such as amateur or packet radio. Setting up a telephone alert system This will discuss a telephone alert system, but it also applies to any system of communication which is one-to-one. In other words, a system in which each member must call each other member one at a time. The simplest and most obvious design for such a system is a simple phone tree, in which each member has a list of some other members to call, each of which in turn has a sublist of members to call, and so forth. The problem with such a schema, of course, is that for it to work, every member must be reachable. If a member cannot be reached, his entire branch of the tree doesn't get notified. This becomes a more significant problem the smaller the number of members each member is supposed to call. A better solution is sometimes called a ring-tree system. It works like this: (1) The top level consists of a committee of 3-5 persons, any one of whom can initiate an alert, normally after conferring with the others, time and circumstances permitting. (2) Each member is assigned to call some number of other members, say eight, organized into a ring, as shown below: Each member in that ring has the phone numbers of a similar ring below him, and also those of the rings under the two members to each side of him in his own ring level. The member first calls a. If a is not reachable, he then calls b and tells him to call the ring under a. If b is also not reachable, then when he completes the ring and reaches h, he asks h to call the ring under a. This process is repeated until he calls all the members in his subring. (3) Each of the members in a ring also has the phone numbers of the other members at their ring level, so if some of the members are unreachable, others in their ring will be asked to keep trying to reach them, especially those on either side of them. When reached, the member should be told if someone else has been calling the ring under him in his absence. (4) If it is likely that three adjacent members in a ring may be unreachable, then the member may need to have the phone numbers of all the rings under them to call directly. (5) Some members may have voicemail or answering machines. If the alert message is left in that recorded mode, then depending on how urgent the message is, it may be necessary to treat that member as unreachable, and have someone else call the ring under him, perhaps after some predetermined period of time deemed sufficient for him to retrieve his message. Store-and-forward nets Another system is made possible by various automatic store-and- forward messaging systems, such as the email system of the Internet and the packet radio network, and fax machines which have the capability of broadcast-sending received faxes to a list of phone numbers. There are even phonemail systems that can retransmit received voice messages to a list of recipients. This system works like the ring-tree system described above, but does not depend on a human being to answer the phone, thus making it more likely that messages will at least be passed on to the machines of everyone in the tree. This is the best solution, but since it involves more cost, may not be feasible for all members. If some members have this capability and some don't, then those that do should probably be placed in the higher levels in the tree. One must keep in mind, however, that such a system is subject to interdiction. Phone or power lines can be blocked or cut. Machines can be disabled, and packet communications jammed or falsified. Therefore, it is important to have backup communications channels. Packet radio can back up telephone communications, and line-of-sight infrared (IR) or microwave transceivers can back up both, in case of jamming or falsification. These are, of course, advanced technology, and may be beyond the budgets or expertise of many militia members. Therefore, it is wise to also consider simpler, older technology, such as hand, flag, or light signals. Every militia unit should have a few members who know Morse code and can use it with various transmission methods if nothing else is available. Encryption methods It will sometimes be necessary to encrypt the messages. For digital messages such as email the best solution is PGP (Pretty Good Privacy), which uses the RSA encryption algorithm. With a sufficiently long key (more than 128 bits), it is effectively unbreakable. It involves the use of two keys, one of which the user makes public, and the second of which he keeps secret. A message encrypted with either key may only be decrypted with the other one. People send to him using his public key, and only he may decrypt the message using his private key. In sending messages, he can use his private key to encrypt a signature block, which he then embeds in the message before encrypting the entire message using the recipient's public key. When the recipient decodes it using the recipient's private key, and then decodes the signature block using the sender's public key, the recipient gets authentication that the message did indeed come from the ostensible sender. Constitution Society, 6900 San Pedro #147-230, San Antonio, TX 78216, 210/224-2868.