some question about secret sharing

[tntstation]

would like to make some modifications to the secret sharing. Currently, it seems that secret sharing involves exchanging frames between all clients. However, I would like clients to be divided into multiple groups, and clients within each group can exchange frames with each other. Can you give me some suggestions?

[qbc2016]

Hello, we use an (n, n)-secret sharing scheme, that is, a secret value is partitioned into n pieces. The value can be recovered if and only if one holds all n pieces. For example, if a client has a secret value $s$, he partitions it into $[s_1, s_2, \ldots, s_n]$, and sends $s_i$ to client$_i$. See here. In my opinion, if you want the clients to exchange their frames within a small group, it may be convenient to maintain a list containing the neighbors among the group, and then send it in a similar way. I'm not sure if this has addressed your question.

[tntstation]

Thank you for your answer. I still have some questions about secret sharing. In this section of the code in sever.py, the AdditiveSecretSharing class sets shared_party_num to int(self._cfg.federate.sample_client_num). However, use_ss is only set to true when all clients participate, so sample_client_num will be -1. I'm confused because in secret_sharing.py, shared_party_num is required to be greater than -1. I'm not sure where I'm misunderstanding.

[qbc2016]

"However, use_ss is only set to true when all clients participate, so sample_client_num will be -1." This is not true. When use ss, we assert that cfg.federate.client_num == cfg.federate.sample_client_num , see here

[tntstation]

thank you，it is really helpful for me