I am having problems understanding this implementation of Shamir's secret sharing with confidentially levels (in this case 3).
I will give the context and then my problem to make it more clear.
in some security system, to share a secret S, they use Shamir's secret sharing. the users in the system are divided to 3 levels of authorization: A, B, and C. To recover S, we need:
A) two users from A
B) one user from A in addition to three users from B and 5 users from C
Assuming that in level A there are only 2 users, and one of them decided to resign. His part of the secret, X, he shares with all of the participants, except the other user from level A, so to recover X we need 4 participants from B and one participant from C. Describe the new secret sharing cryptosystem. What does each participants hold and how to recover S?
I am having a real hard time understanding this cryptosystem variant of Shamir's secret sharing. There are a lot of variants here.
I really don't understand what each participant hold and how to recover the secret S in this complicated scenario.
Could you please elaborate on it to help me understand it better? I feel totally lost.