|
How to use FTP_ITC (Inter-TSF trusted
channel) ?
I've been pondering over
it, and yet I'm not clear about
it.
Could someone teach me the usage in the
following situation?
-----------------------------------------------------
Situation:
We are
writing the ST for a TOE.
The TOE communicates
with other remote trusted IT products
through the
Internet.
The security
objectives for the TOE is to protect
the transmission data
from modification.
-----------------------------------------------------
Then, it is no doubt that the TOE needs
FDP_UIT.1(data exchange integrity).
Then, it needs to
specify FTP_ITC.1(Inter-TSF trusted channel) too,
since FDP_UIT.1 has the dependency on
FTP_ITC.1.
The requirements of FTP_ITC.1
are:
a) to provide logically distinct communication
channels
b) to provide assured identification of its
end points
c) to provide protection of the channel
data from modification. d) to initiate communication by either the TSF
or the remote trusted IT product
Now, in order to express the security
functional requirements in the ST,
we have the following
choices.
Choice-1:
The TOE fully
supports FTP_ITC.1.
Choice-2:
The TOE supports a part
of FTP_ITC.1.
For example, c) and d).
The IT environment for the TOE support others (i.e., a)
and b) ).
Choice-3:
TOE does not support FTP_ITC.1.
The IT environment fully supports FTP_ITC.1.
Choice-4:
Both the TOE and the IT environment for the TOE
do not support FTP_ITC.1
However, the TOE supports c), and hence the TOE satisfies
the security objectives without
FPT_ITC.1.
So, the non-satisfaction of a dependency on FTP_ITC.1
does not prevent the FDP_UIT.1 adequately addressing
the security objectives.
*****
Now, which one is the most plausible and acceptable choice
for the writing of the ST?
Followings are my thoughts.
About the choice-1.
Naturally, the TOE
executes send/receive command
to communicate with the
remote trusted IT product.
However, the network functions are
mostly provided
by the underlying
OS (the IT environment of the
TOE such as Weblogic6.1). Hence, this is not plausible.
About the choice-2. I think this is plausible.
About the choice-3
I think this is not plausible, since d) is not the task of IT
environment,
but the task of the TOE.
About the choice-4
I think, FDP_UIT.1 needs definitely FPT_ITC.1 in the
situation.
So, I think, this is not
plausible. However, some people strongly suggest this is the correct
choice.
They say, "It is impossible to provide logically distinct
communication channels in the Internet. So, it is
imposible to use
FPT_ITC.1 in the Internet communication.
******
How do you think about this?
Regards,
Yokota
|