User's Manual

Internal Encoding
RFI-148 & RFI-900 High Output Power Paging Transmitters User Manual Page 45 of 134
4. In the “Single Key Entry” table, enter the chosen encryption key, in ASCII HEX format, a quarter in
each of the four columns, being mindful of their order.
5. Enter this same key into the paging receiver.
6.6.2 Encrypting
Having completed the key-sharing procedure, messages can be encrypted as follows
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:
1. Enable the encryption feature (ATS220=1).
2. Indicate preferences:
a. All messages are to be encrypted (ATS221=1)
b. Only messages to specified capcodes are encrypted (ATS221=0):
i. All capcodes that fall within a range specified by upper (ATS242[1]) and lower
(ATS242[0]) limits AND/OR
ii. Individual capcode values as listed in the “Individual Capcodes” table (ATS241).
3. Optionally verify the configuration by issuing a few test messages to the relevant capcode(s) (Refer to
6.4)
6.6.3 Security
Note the following security features:
• Entry of the customer password is necessary to reveal encryption keys.
• The customer password is provided as an input to the key generation algorithm, such that purchase of
an RFI-148 by a different customer cannot reproduce encryption keys of another.
• The “End Password Session” routine (ATS224) is provided to allow immediate concealment of any
displayed encryption key.
• After 30 seconds of inactivity of the Capcode field (ATS226) or ay key field, all encryption keys will
be concealed.
• On concealment of encryption keys, the customer password must be re-entered to reveal the key.
• The customer password cannot be viewed or changed – it is assigned just once, at the factory.
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It is not currently possible to apply different encryption configurations on a per-stream basis; messages to a specified capcode will
be encrypted or not regardless of their origin.