Quickstart Guide
www.cryptophone.de
IP
GSMK CryptoPhone 400
Send a Secure SMS
Before you can exchange secure SMS
with a contact, you need to complete a
key exchange. To initiate the key
exchange go to Contacts, highlight the
name of your contact and select
"Manage Keys" from the menu.
You can now initiate the key exchange
by pressing the Invite button.
For each key exchange, five SMS will be
sent and received, containing the public
key material. After key exchange is com-
pleted, you will be asked to verify the
new SMS key by either a phone call or
other means. The six letters of the
cryptographic fingerprint of your key
are shown in the display. Read out the
three letters that are shown under
"You say" and verify that the letters
your partner reads out are the same as
shown under "Partner says".
You now can exchange
encrypted SMS with
your partner using the
New Message icon.
The SMS key is kept in the Secure
Storage and is used to generate session
keys for your future encrypted SMS
exchanges with this partner. It can be
renewed from the "Manage Keys" menu.
Lock the Secure Storage
To lock the Secure
Storage press the Lock
icon. Then press the
Lock Storage button.
Emergency erase
In case a capture of your phone by
unfriendly elements is imminent, you
can use the emergency erase function.
It overwrites all key material and sub-
sequently the rest of the flash memory
of the phone. You can access this
function from the Lock screen.
Note that an emergency erase will take
several minutes.
Reset
To reset your CryptoPhone, remove the
battery, re-insert it and switch on the
phone again.
Cold Boot
If you want to switch to a different
Security Level (see
1
) or reset your
phone to factory state, so that a new
empty Secure Storage is created, you
need to cold boot your phone. Please
note that all data stored on the phone
will be no longer available. The data is
not securely overwritten in memory like
with an Emergency erase and can in
theory be reconstructed by forensic
methods (which does not affect the
encryption of the Secure Storage).
To cold boot your phone you need to
take out the battery and re-insert it.
Then hold Volume Up and Down
simultaneously while briefly pressing
the Power button. Then follow the
instructions on the screen.
the same as shown under "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 dropouts
or otherwise bad audio, try calling again
and try to find better network coverage.
Call quality can be sub-optimal in fast
moving vehicles.
numbers of your contact, if you want to
exchange secure SMS.
You can edit the contacts later.
Make A Secure Call
Press the Contacts button, select the
contact and either press the Dial button
or choose "Call Secure" from the Menu.
If your partner is available, you will hear
a ring tone. When he picks up, you will
hear a special tone sequence, indicating
the cryptographic key exchange is in
progress, and "Key Exchange" is shown
in the display.
After key exchange is completed, six
letters are shown. This is a cryptographic
fingerprint of the unique session key
used during your secure call. When in
call, read out the three letters that are
shown under "You say" and verify that
the letters your partner reads out are
9
10
11
12
13
8
1
...
C
M
Y
CM
MY
CY
CMY
K
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