mshankarak
asked on
FCS in Authentication
Hello Experts,
Can FCS in the Ethernet frames be utilized in developing an authentication check for data sent across network ? If possible, then how can this be done ? If not, then why ?
Many thanks
Can FCS in the Ethernet frames be utilized in developing an authentication check for data sent across network ? If possible, then how can this be done ? If not, then why ?
Many thanks
ASKER
I appreciate your approach.
FCS is frame check sequence which is usually a CRC-32 code used for error detection. In the Ethernet frame format it is the final 4 bytes (32 bits). The error detection is carried out following the principles of CRC.
FCS is frame check sequence which is usually a CRC-32 code used for error detection. In the Ethernet frame format it is the final 4 bytes (32 bits). The error detection is carried out following the principles of CRC.
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ASKER
As CRC functions, the message is divided by a polynomial function (n+1) bits to produce a CRC/FCS of n bits which is appended to the message.
I don't think all the frames from the same client will have the same value as the message being sent across would be different every time and the message is crucial in deriving the CRC.
2 frames from two different computers MAY have the same FCS value.
I don't think all the frames from the same client will have the same value as the message being sent across would be different every time and the message is crucial in deriving the CRC.
2 frames from two different computers MAY have the same FCS value.
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ASKER
Thanks. Correct me if I am wrong, as FCS doesn't have any user or device info it cannot authenticate a message being sent over the network.
ASKER
Hey, I have just added a new comment on the LLC question. Would you mind checking that out for me ?
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So instead of just out right answering your question I will ask you questions to see if you can figure out the answer on your own. Even if this is not a class related question, this will help you to get thinking about what you are asking.
Do you really understand what FCS is? If so, explain so we know that you do.