Also allow me to make some suggestions from an area I do have a limited amount of expertise in (measuring electrical resistance not being one of these areas). Also will post some 'open research' questions. First, is RFID the best transmission technology? Battery powered RFID can transmit up to 100 feet away I believe. It is certainly not going to work if we use RFID that is not battery powered as transmission distance will not be far enough to get a reading. Let's think of other transmission technologies that we could use. One idea I just had is using GSM chips. I know some leet carders use skimmers that text the card data to a phone, so they only need to worry about installation of the skimmer and not pick up. Perhaps we could also use GSM chips and have the state signal sent to a predetermined phone number. This would allow for detection of interception from a tremendous distance, but would also require the package to be in an area with reception. Could even have it send the signal via cellular network to a VOIP number that is accessed anonymously or something. This also has the added advantage of the vendor and customer both being able to check for interception, as a physical presence near the package will not be required. Second, what sensors can we use? The first suggestion by Enelysion was to use photovoltaic cells that trigger when light hits them (thus when the package is opened, we would assume). A limitation of this is the potential for packages to be opened in dark rooms. Things we need to take into consideration include ease of creating the product, ease of anonymously obtaining the required components, size of the components (we want these to be as small as possible), cost of the components (the cheaper the better, although for huge bulk orders cost will be less of a consideration), etc. One potential technique someone who is working on a design for these mentioned is measuring the electrical resistance of the packaging material, you seem to think this is a bad idea and I would love to hear why so I can forward the information on. Other potential sensors include x-ray, infra-red, etc. These would offer the advantage of being able to determine if a package was scanned at all, although the primary thing we are concerned with is if the package was opened. Another potential thing that has been mentioned is the use of oxygen detectors with the chip being vac sealed with the drug shipment. As far as what is broadcast, I propose that we use a PRNG with a secret seed that is set by the sender after the package is created (wirelessly set). The chip then begins to run the PRNG and broadcasts its current state every certain amount of time, after a timer runs out. The output of the PRNG will either be a 1 or a 0, and this is determined by the seed. Someone who knows the seed will be able to determine the state of the PRNG out to an arbitary bit length. Someone who does not know the seed will have a fifty fifty chance of being able to mimic its resulting output for a given broadcast (either 1 or 0). The person the pack is sent to can measure the output of the PRNG (via the transmission system we go with) and compare it to what the output of the PRNG should be (which they can determine since the sender of the pack sends them the seed via asymmetric encryption). If it matches up for enough broadcasts, it can be determined that the seed is still present in the volatile memory. If it doesn't broadcast or the broadcast does not match up with what the seed should produce, interception (or malfunction) can safely be assumed. I propose that the person getting the pack is not required to broadcast to it, as they could very well compromise their position by doing so. The chip should instead be on a timer and set to broadcast after a set amount of time (when it is assumed to be in the box waiting for pick up). The chip can not broadcast while it is in transit or else the attacker can start to look for broadcasting packages and the chip will turn into a beacon. However, I am fairly certain that there are broadcasting mechanisms that attempt to hide the signal that is broadcast from someone who does not have knowledge about the parameters of the broadcast, I am not an expert on wireless transmission but I have friends who are I will ask them more about this. It may be feasible to have a hidden broadcast that is difficult for a third party to detect even if they are looking for it, although again I am not certain if we will be able to implement such a sophisticated system with our chips. LPI is one such system for signal transmission with low risk of detection, https://en.wikipedia.org/wiki/Low_probability_of_intercept_radar . Then we need a mechanism in place to quickly wipe the volatile memory after one of the sensors is triggered, or else customs may be able to flash freeze it and obtain the seed. Cutting power after one of the sensors is triggered may not be enough. Design goals should be to make the chip as fully features as possible while also making it as cheap and easy to produce as possible, and perhaps most important as small and discreet as possible. Please weigh in everyone who has any expertise relating to any of the areas involved with this, or anyone who has comments opinions questions or suggestions. Let's get this shit done! Using these in addition to fake ID boxes will make importing large bulk far safer, as we will always be able to determine when an interception has taken place prior to attempting pick up.