“Key Exchange” is shown on
the display and you will hear
a special tone sequence indi-
cating that the cryptographic
key exchange is in progress.
After the key exchange is
completed, six letters are
shown. These six letters are
a cryptographic fingerprint
of the unique session key
used during your secure call.
Once the call
has been es-
tablished, read
out the three
letters that are
shown under
the label “You
say” and verify
that the letters
your partner
reads out to you
are the same
as shown under the label that
reads “Partner says”.
If they do not match, you
should not consider the line
secure.
The quality indicator icon
changes color depending on the
delay and overall quality of the
connection. If it stays orange or
red, try to change to a location
with better network coverage.
If it stays red and your call has
glitches or bad audio, change to
a location with better network
coverage, try disconnecting
and reconnecting to the secure
network (
see
section
5
), then call
again.
Please note that call quality can
be sub-optimal in fast-moving
vehicles.
