I stumbled upon this great explanation of telephone traffic analysis and thought I'd share it with the list: Remember also, as far as security goes, that individuals always have the ability to add their own encryption to a system. But I would argue that encryption is also of minimal protection against a knowledgable telephone company or government with message traffic flow tracking capability. This is a capability that every phone company has since they use it to generate your bill every month. Consider the following: Some undesirable activity (to the govt or phoneco) is happening. The govt/phoneco (govco) is able to identify one or more persons involved. (now known as targets.) Targets: *1* *2* *3* They track and compare the frequency of calling patterns made by the targets. Now they know the "calling circle" of the targets. They expand the tracking pattern and start looking for cross overs. Targets: *1* *2* *3* / | \ / | \ | Level 1: A B C D E A F When they start to find a commonality (by Phone # or account holder(s)) they can begin to build the list of those persons most often called within the identified target group. In the above 'A' is common to targets *1* and *2*, thereby implying that the "group" is composed of *1*, *2*, and 'A'. Those most often called are the "key communicators", regardless of any formal or informal organization or public presence. By iterating this process recursively the entire organization and any supporting sympathizers can eventually be located. Both by members of the target group and by others outside the group who may not have any knowledge of other members of the group or even of themselves being in a group. Further, since all phone numbers are tied in the planning databases to physical locations and to billing addresses, enough data can be gathered to completely locate and identify (for further evidence research and cross referencing) members and supporters. Notice that this works even in those cases where no formal organization exists. Notice that this works regardless of whether the communications in question are encrypted or not. Applying this means that a movement, or any organized or coordinated activity could be disrupted by proper targeting of those who are the true key communicators. Actions as simple and subtle as cutting off phone service, placing bad credit reports, starting a tax audit, getting the person a better paying job in a different area, etc., etc. could all be just as effective as outright arrest and harassment. If they don't work, then things would escalate. So consider this as well and don't rely just on encryption to keep yourself secure. -- Lucky Green <shamrock@netcom.com> PGP public key by finger