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Police Radio


This essay does not describe an existing computer program, just one that should exist. This essay is about a suggested student project in Java programming. This essay gives a rough overview of how it might work. I have no source, object, specifications, file layouts or anything else useful to implementing this project. Everything I have prepared to help you is right here.

This project outline is not like the artificial, tidy little problems you are spoon-fed in school, when all the facts you need are included, nothing extraneous is mentioned, the answer is fully specified, along with hints to nudge you toward a single expected canonical solution. This project is much more like the real world of messy problems where it is up to you to fully the define the end point, or a series of ever more difficult versions of this project and research the information yourself to solve them.

Everything I have to say to help you with this project is written below. I am not prepared to help you implement it; or give you any additional materials. I have too many other projects of my own.

Though I am a programmer by profession, I don’t do people’s homework for them. That just robs them of an education.

You have my full permission to implement this project in any way you please and to keep all the profits from your endeavour.

Please do not email me about this project without reading the disclaimer above.

This project is to build a prototype secure police radio system.

The main problem with current police radio is the information is sent in analog from free for everyone to listen to, including the crooks. Your job is first to learn as much as you can about police scanners and how police use them. You also want to see if you are reinventing the wheel. Then your job is to write software to simulate a secure digital system. The voice would be sent encrypted and addressed to just those who are supposed to hear it. The secondary reason for doing this is to reduce pestering officers with chatter not relevant to them, so they can more fully pay attention to what does concern them.

This is similar to what Skype does namely VOIP (Voice Over Internet Protocol), with added conferencing and encryption.

The problem is, if you send the message separately to each recipient each encrypted with their key, you would need orders of magnitude more bandwidth. So each recipient needs several private keys, one for the police force in general, one for him individually, one for his squad etc.

The scanner could only decode messages for which it has the key.

You want the ability to change the private keys frequently in case the system is ever compromised, or you want them burned into hardware in some way they could not be extracted. Some USB (Universal Serial Bus) flash drives have such a hardware secret key.

When you have your prototype working, I have to sell the idea to a conventional scanner company.

USB flash drive

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