Motorola SECURENET
 | |
|---|---|
| Frequencies | 137 MHz,174 MHz,400 MHz,420 MHz,450 MHz,520 MHz,941 MHz,851 MHz |
| Frequency Range | 137 MHz - 941 MHz |
| Mode | FM |
| Modulation | FSK,4FSK |
| ACF | — |
| Emission Designator | — |
| Bandwidth | 16 kHz |
| Location | Worldwide |
| Short Description | Motorola SECURENET ("analog" encryption) was a secure voice option for conventional and Motorola Type II trunked systems, encoding the voice using 12kbps CVSD and encrypting the bitstream. It is easily identified by the 6 kHz tone at the end of transmission. As it is not 12.5 kHz FCC narrowbanding mandate compliant, it does not see much use anymore. |
| I/Q Raw Recording | Download file |
| Audio Sample | |
Not to be confused with the Motorola Type II trunking system
Motorola SECURENET is an obsolete voice encryption algorithm supported by Motorola MX300, Saber/Spectra, STX, MTS/MCS, ASTRO Saber/Spectra, XTL/XTS, and APX radios. Standard SECURENET operation begins with analog voice sampled and digitized with CVSD at 12 kHzKiloHertz (kHz) 10^3 Hz, and the resulting bitstream is encrypted before transmission using 2-level FSKFrequency-Shift Keying at 4 kHzKiloHertz (kHz) 10^3 Hz deviation. Motorola made a 4FSK4-Level Frequency Shift Keying 2.4 kHzKiloHertz (kHz) 10^3 Hz deviation variant named FRED (Four-level Recovery Encode/Decode) for use with 800 MHzMegaHertz (MHz) 10^6 Hz NPSPAC frequencies and with simulcast systems. There is minimal data transmitted alongside the CVSD voice to prevent interruptions in the voice audio, and due to the encryption algorithms' high-entropy output, SECURENET sounds like noise when tuned with a conventional FMFrequency Modulation receiver (with exception to the 6 kHzKiloHertz (kHz) 10^3 Hz end-of-transmission tone). SECURENET decoded audio quality is poor due to the heavy lowpassing necessary with CVSD.
SECURENET can be used simplex, through a repeater (capable of passing unfiltered audio, or via reconstruction of the bitstream), or as a system voice option of a Motorola Type I or Type II trunked system. If MDC1200 pre-transmission PTTPush To TalkPress to TransmitMinistries of Postal, Telephone, and Telegraph Service (Soviet Agency)-ID/RAC is enabled on a secure channel, the radio will send the MDC in clear analog with any configured PL/DPL, drop PL/DPL after sending MDC1200, and proceed with SECURENET voice; this permits repeaters to use PL/DPL squelch and/or MDC Repeater Access Codes with secure voice.
Algorithms[edit]
SECURENET supports several algorithms:
- DES 56-bit
- DVP 138-bit
- DES-XL 56-bit
- DVP-XL 96-bit
- DVI-XL (export version of DVP-XL)
- DVI-SPFL (8 special flavors of DVI-XL)
- FASCINATOR (Motorola's implementation of Type I SAVILLE)
XL algorithms use counter addressing and periodic sync pulses to improve weak-signal reception; range is still poorer than clear analog voice and audio quality is poorer than non-XL algorithms.
Emissions Designators[edit]
16K8F1E - SECURENET NPSPAC designator
20K0F1E - SECURENET standard (2FSK) designator
Additional Audio Samples[edit]
- SECURENET with MDC600 PTTPush To TalkPress to TransmitMinistries of Postal, Telephone, and Telegraph Service (Soviet Agency) ID
- SECURENET with MDC1200 Key ID and PTTPush To TalkPress to TransmitMinistries of Postal, Telephone, and Telegraph Service (Soviet Agency) ID
- SECURENET with MDC1200 Key ID and PTTPush To TalkPress to TransmitMinistries of Postal, Telephone, and Telegraph Service (Soviet Agency) ID from Astro-series and later radios
- Recovered SECURENET audio using non-XL mode
