An informative video about 3 Indian Private aerospace industry
Excellent Updates on GSAT
Let me go through the whole cycle of encryption as is used with communication systems today.Question? : This OCT - will this be encrypted? - How does one encrypt Optical communications?
Excellent Write up - Very Informative - Definitely not a rant!Let me go through the whole cycle of encryption as is used with communication systems today.
Data is quantifiable by energy. That is the very basis of computers. All data can be expressed in terms of the binary( 0 & 1 ). Thus information flowing between two nodes, say satellite and a ground terminal, if properly tapped can be completely accessible. That's the problem with RF based communications. The energy from the antennas are radiated in all directions equally. Thus making it possible for multiple users to access it as long as you are in range. To ensure information stays private it needs to be encrypted. Encryption is essentially jumbling up the 0s and 1s in a very specific manner. The end result is still 0s and 1s, but everything is out of order.
Lets take an example, if I say :
then 3= ??
You can easily identify the pattern and say 3=C. This is what encryption does, its just the maths is a lot more complex with multiple exceptions built in. Thus it take a long time to solve the problem and even if solved some data remains out of reach. You will hear encryption systems described as 8 bit, 16 bit, 32 bit, 64 bit etc. What this means is that the key to solving the encryption has 8 digits of 0s and 1s, 16 digits etc etc.
The longer the key the more difficult it is break. But not impossible. With the advent of quantum computers these encryptions will be broken in no time. To counter this proble QKD are being developed. India is in a pretty advanced state with this development. Go through this thread :
Any kind of optical communication will use quantum bits for communications. This will render the entire data stream un-tapable. The GSAT-29's OCT is essentially a laser and sensor combined together. Now to tap in to the OCT you need to have your tapping equipment exactly where the laser is targeting. The target ground terminal is probably going to be some highly secure ISRO ground facility. Remote tapping is not an option. This will make the communication virtually impossible to break into.
There are problems too. Optical communications tend to be more energy consuming than their RF counter part. Bad weather, receiver mis-alignment etc can be problems too. The OCT is still very much experimental and for the foreseeable future a bulk of our data comms will continue to be RF based. However the RF comms can adopt QKDs to make it more secure.
Sorry for the long rant !
Not true at all. In fact ISRO is insists on indigenous design & manufacture even in not so high tech areas like satellite buses. ISRO does import stuff that's not available in India. Like processors.I read somewhere that 50 to 60 % of Indian sattlite components are just imported from abroad & screw drive here.....for strategic sector it's even higher. how much truth in that @Gautam ?
Component testing was supposed to end this year. COVID has played spoilsport. From sat pics the test stand at LPSC, Mahendragiri seems to have been completed. No official announcements yet. The next phase is hot test of the engine at that test stand. ISRO has called for tender to augment the SLP to house Kerosene for fueling purposes. SCE-200 is the only engine with ISRO that uses Kerosene as fuel.What's the update with SCE 200 engine