E.F. Johnson Company 53SL ES Series, Руководство по эксплуатации

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53SL ES Series Mobile Radio Operating Manual April 2009 8-1
S
E C T I O N
Section 8
Secure Communication (Encryption)
This radio may be equipped to provide secure communication on some or all channels.
This feature encrypts the voice so that it can be understood only by someone using a radio
equipped with a similar encryption device and encryption codes.
If equipped with the Clear/Secure option switch and the current channel is programmed to
allow switch selection, secure communication can be manually enabled and disabled by
that switch. Otherwise, channels are strapped to Clear or Secure operation (see Section
8.3). Secure communication can be programmed on a per channel or per talkgroup basis to
operate in various ways. When a secure call is received, the LED indicates red and
is
indicated in the display.
8.1 Encryption Algorithms
8.1.1 SecureNet™
SecureNet encryption digitizes the voice and then encrypts it using the DES algorithm. It
uses a 64-bit encryption key. The SecureNet protocols include the following algorithms:
• DES (Data Encryption Standard) provides a level of security, and also uses cipher
feedback. It was originally designed to be used only by the Federal government.
• DES-OFB - A form of DES encryption for digital channels that uses output feedback.
This protocol does not result in the degraded range that occurs with analog channels.
Note Using SecureNet may result in reduced range.