TARGATE Question on Network security

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TARGATE Question on Network security

Postby mrprajesh » Thu Nov 21, 2013 2:30 pm

Image

I eliminated a and c as PK Csystem has 2 key [public and private] so 17*2=34. it was told d is answer [nC2] but could not understand the theory behind it, any thoughts?
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Re: TARGATE Question on Network security

Postby sameer2009 » Thu Nov 21, 2013 3:19 pm

mrprajesh wrote:Image

I eliminated a and c as PK Csystem has 2 key [public and private] so 17*2=34. it was told d is answer [nC2] but could not understand the theory behind it, any thoughts?

Public key system:
Every person has 2 keys
17 persons so total = 34 keys

Secret key system:
Here every pair of person will have a common key
eg lets say 3 persons a, b, c
[a, b] will have common key
[a, c] will have common key
[b, c] will have common key
therefore find distinct pairs from a set of 17
therefore 17C2 = 136
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Re: TARGATE Question on Network security

Postby mrprajesh » Thu Nov 21, 2013 3:28 pm

cool..!! Thanks.
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