WikiStart » History » Version 34
Anonymous, 04/22/2017 04:04 PM
Change WireShark file name.
| 1 | 23 | = Welcome to OP25 = |
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| 2 | 18 | OP25 is a project to bring together folks that are interested in implementing APCO P25 using a software-defined radio. Our goal is to build a software-defined analyzer for APCO P25 signals that is available under the GNU Public License (GPL). |
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| 4 | 18 | APCO Project 25 is the digital communications standard used by many police and emergency services throughout the world. Most notably the US, Canada and Australia deploy systems based on P25. Compared to existing analogue systems P25 offers improved spectrum use, coverage and flexibility. Provision is made to ensure the confidentiality of traffic, to allow the use of trunking and the provision of data in addition to voice services. |
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| 6 | 25 | Hardware scanners such as the Uniden BCD996T offer APCO P25 functionality but software-defined radio (SDR) offers significantly improved flexibility. For example, software radio approaches can receive many channels at once, handle both voice and data (including the trunking control channel), decrypt encrypted traffic when the key is known and log traffic to disk for later analysis. With the right software an SDR is a powerful analysis tool for debugging and monitoring of P25 networks. |
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| 8 | 18 | == Project Tasks == |
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| 9 | From here we have a number of tasks that immediately suggest themselves. In increasing order of difficulty these are: |
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| 10 | 3 | * Understand P25, the physical layer and the messages being passed over the air. |
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| 11 | 31 | * Implement a decoder which takes P25 signals and produces a message stream. |
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| 12 | 3 | * Extend the !WireShark sniffer to allow sniffing of P25 messages. |
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| 13 | 27 | * Analyzing the various security issues and demonstrating the insecurity of P25 systems. |
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| 14 | 29 | * Implement an IMBE decoder to recover voice traffic. |
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| 15 | 18 | * Provide a practical logging service for P25 monitors. |
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| 16 | 1 | * Locate and track the locations of P25 mobile stations. |
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| 18 | 21 | As all Wiki pages, this page is editable so these ideas are not fixed in stone. Developers can simply click on the "Edit this page" link at the bottom of the page (although it is worth familiarizing oneself with Wiki formatting beforehand). |
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| 19 | 1 | ||
| 20 | == Starting Points == |
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| 21 | * [HardwarePage Hardware] -- The recommended hardware for this project. |
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| 22 | * [SoftwarePage Software] -- An overview of the project software. |
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| 23 | 33 | * [BuildInstructionsPage Build instructions] -- How to get and build OP25. |
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| 24 | 31 | * [DecoderPage Decoder] -- A GNURadio program that turns a P25 signal into an audio and message stream. |
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| 25 | 34 | * [WireSharkPage Patching WireShark] -- Patches to !WireShark that allow for the sniffing of P25 traffic. |
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| 26 | 16 | * [http://www.sedition.org.au/p25-specs Specifications] -- The APCO P25 specifications. |
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| 27 | * [QandAs FAQs] -- Frequently asked questions and answers. |
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| 29 | == Email lists == |
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| 30 | 24 | * [http://tech.groups.yahoo.com/group/op25-dev/ op25-dev] -- elist for developers to discuss and manage the project. |
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| 31 | * [http://groups.yahoo.com/group/project25/ Project25] -- elist discussion forum for APCO Project 25 and related technologies. |
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| 33 | 18 | == Related Projects == |
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| 34 | 26 | Op25 depends on a number of free software projects: |
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| 35 | * [http://www.gnuradio.org GNU Radio] A framework for digital signal processing and software radio. |
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| 36 | * [http://radiorausch.googlepages.com/GnuradioFourLevelFSK.html Radio Rausch FSK4 demodulator] A 4-level FSK demodulator. |
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| 38 | 18 | OP25 is only one of a number of projects in this area and you should check out [http://openp25.org/ OpenP25] and |
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| 39 | [http://wiki.radioreference.com/index.php/UniTrunker Unitrunker] for related work. |
