4 Final Report - Emits - ESA

4 Final
Report
1.8E14 FLOPS per product.
The currently available hardware capabilities can be estimated using the example of a SUN SPARC
Enterprise M 9000 Server, which provides a computing power of 1.032 TFLOPS. The M 9000 is one of
the most powerful servers available today. As a result, the M 9000 would be able to compute the
above-mentioned product within 180 seconds (1.8E14 TFLOPS / 1E12 TFLOPS).
The automatic dissemination of the products to the dedicated Service Segment for the generation of
higher level products / value adding can be facilitated by assigning Request-IDs, by which each user
request, the subsequent tasking within the Spacecraft's schedule and the finally delivered product can
be identified and automatically routed to the end-user.
4.6.2.7 Encryption Concept
From a generic point of view, the encryption of the payload data shall ensure the confidentiality of its
content. The reason why this data shall be kept confidential is basically motivated by the following two
headlines:
• Public safety
• Commercial aspects
The consideration of public safety aims at safeguarding the EO data from misuse by illegal groupings
such as criminal associations or even terrorists. This aspect has already been considered by different
legalisation authorities worldwide.
The commercial aspects cover all those issues which are related with the property rights of the image
data. In this respect, the satellite data should be safeguarded from eavesdropping or theft in order to
be able to retail the image products to commercial users.
As a result of the previous considerations, the encryption concept should be simple. A commercial
level encryption concept should be adequate.
One of the main issues will be to ensure that, in case of deployment of users’ terminals for emergency
applications, only the user terminal which submitted the observation request should be able to receive
the image(s) acquired (in addition to the core Payload Data Ground Segment, which would receive all
images in parallel for the sake of their long term archiving).
Among the possible concepts for encryption, the following alternatives can be considered:
• One key per image: this is the most secure but also the most complex alternative
• One key per time slot: in this concept, the keys would be changed at regular time intervals
e.g. each day, each week, each month
• One key per receiving station: each “user” receiving station would then be able to decrypt
only the images which have been encrypted with this station’s key. The core PDGS would
receive all images and then would also need to receive all keys.
One specific issue with respect to users’ receiving terminals will be how to distribute the keys, which
may be an issue in case of deployment of the stations where no permanent network is available. Note
that this issue extends to the distribution to the users’ stations of any other kind of auxiliary data
needed for data reception (pointing data if the satellite is not on a geostationary orbit, time slot for data
reception) and for processing (auxiliary data, orbit data).
Doc. No: GOC-ASG-RP-002 Page 4-85
Issue: 2
Date: 13.05.2009 Astrium GmbH