ATCommands
•‘Fudge’ is Mark Stein’s password on the remote system
•‘Vanilla’ is the password on the local modem
•‘Access granted’ confirms that the passwords are correct
•Secondary keys mismatch if the secondary KEY, IV or KE are different
Enabling Rotating Secondary Keys
❑If you enter a KE of 00 for the user, then the secondary key will remain the same for each connection.
❑If the KE is not 00 then this value is used as a seed to create a random new secondary key for the user on each connection.
❑After the initial connection is made with the KEY, IV and KE you have entered, these values will change on both modems to new values which are not accessible by any means.
❑If an event occurs that corrupts the KEY, IV or KE on either modem, then both modems will have to be manually set back toa known starting point.
☞To ensure random unknown keys, make two connections between the secure modems after they have been initialised.
Symmetrical Operation
❑Either modem can originate the call.
❑Remote modem’s password is first.
❑Local modem’s password is second.
Automatic Synchronisation
❑The keys only change after a successful connection is achieved at both ends.
❑If either modem drops out during the security handshake before the CONNECT message, the modems will automatically resynchronise on the next connection.
Password Expiry Option
You may specify the number of days you have before the password must be changed. By default this option is OFF, to enable it select the C option from the security menu. You will then be prompted for the number of days before a password expires
❑When a password is within 5 days of expiry a message will be given before the connect message.
❑After the password has expired, you will be informed and will not be allowed another connection until a new password is entered. The access record also notes if you have been informed of the expiry.
❑Either the remote or the local password or both may expire.
☞There is no real time clock inside the modem. When the modem is turned off the clock stops. Therefore the expiry timers actually time the number of days that the modem is turned on and not elapsed days.
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