An odd concept occured to me, in which a multiphasic system could be used to transmit power effectively only to authorized taps. In a small scale digital system, this would consist of a transmitter circuit which would be a specially controlled switched mode power supply that would transmit power pulses into a three or more bus conductors with a nuetral return conductor. These bus conductors would then be tapped by authorized devices through receiver circuits which have a key which allows them to predict and efficiently convert the pulses via switched mode decoders into the desired power to the tapped device. Any unauthorized device would have to rely on predictive algorithms to try and guess the pulses in order to leech power. The effectiveness of the cryptographic system could be mathematically determined by taking the ratio of the desired power over the actual power which can be leeched by the best possible predictive algorithms. The goal of the design would be to get that ratio to be as high a number as possible.
In a larger scale AC system, the concept would be similar except more phases would be preffered. In order to convert a three phase power system into a cryptopower system it would need to be rebuilt into a six or nine phase transmission line. This is a necessity in order to ensure that the tranmitted pulses still aggregate such that there is little to no nuetral current. So a three phase system would be converted to a nine phase cryptopower system by redistributing the A phase current to the a1, a2, and a3 phase conductors of the cryptopower system, and so on with the B and C phases in the same way such that a1 is related to the original A by the same proportion as b1 is related to B and c1 is related to C. The effectiveness of the cryptography would again be computed by determining the ratio of ideal transmission to an authorized tap to the best possible transmission to a pirate tap.
There is at least one clear use for such a system. In a situation where access to a power bus is for some reason physically unsecured (for ease of use or convenience, perhaps) this system could still limit power to unauthorized users or perhaps just provide a “preferred” power tap to authorized users with better efficiency then the unauthorized taps.
The key to this concept seems to be the switching speeds and switching losses of the PMOS or thyristor devices at the transmitting and receiving ends. For instance if the transmitting end relies upon devices that can carry a great deal of current but cannot switch frequently, then a low power unauthorized device can take power just by measuring the incoming signals and responding accordingly with its much faster transistors. Thus, it can be stated that any such crypto system can be “beat” by a device who’s power consumption is much less than the the capacity of the tranmitting source. Similarly, the systems would all be theoretically vulnerable to technological advances. If a crypto power system is constructed with current technology, it is feasible that superior switching devices can be created that would render the system completely insecure to new unauthorized devices. Finally, any reasonably priced system would likely be vulnerable to custom cutting edge present day technology relying upon experimental or otherwise prohibitively expensive materials for tge tranmitting system.
For those reasons, crypto power transmission in the previously stated form seems too much trouble for its alleged benefit, especially when compared with alternative device credentialing systems. For instance, when taps must be convenient and accessible by everyone, but the power use needs to be controlled, then the tap can deliver a challenge or series of challenges that only authorized devices can respond to correctly. Take an airport power socket for example. Each of those can be modified with series signal blocking inductors on the line and neutral, and then serial signals can be coupled on to the plug side line and neutral to transmit a challenge and receive a response from a plugged in device. If the response is incorrect, then a relay opens the outlets circuits, leaving it dead except for occassional additional challenge transmissions. Such a system could be beaten by bypassing the outlet, welding the relay contacts closed with an exceptionally large current surge, or by simple power sharing in which someone plugs in a power strip or splitter that appears to the outlet to be an authorized device. Nevertheless, one would get a comparable system without the need for rewiring or for additional switched mode power supplies.
Thus, the previously described crypto power transmission technology is best relagated to a position as a “puzzle box” technology that could be incorporated into custom systems to delay, impede, and confuse unwary tinkerers, but that wouldn’t otherwise have any widespread usefulness.