Question

There are 5 participants in a Symmetric Key system and they all wish to communicate with each other in a secure fashion using Symmetric Keys without compromising security. What's the minimum number of Symmetric Keys needed for this scenario keeping in mind that each pair of participants uses a different key

Answer 1

10 keys.

Step-by-step explanation:

There are 5*4/2 = 10 pairs in a group of 5. You need that many keys.

Every member of the group will have 4 keys.

If you draw 5 dots on a piece of paper and connect each one with a line, you'll be drawing 10 lines. Each line needs a key.