This question is actually continuation of my previous one.
to implement solution there, I have to generate random data for padding (I will use PSS).
- There are N parties. Up to M are malicious adversaries (were trusted, but got taken over silently). I will be happy with solution for any N and M = 1.
- Parties should send to each other some random data d[i] and each party based on all d[1..N] should generate some final random value R.
From one side, value should be one and the same for all parties, i.e. calculation should be a fixed predictable process and all parties should get one and the same value R. From another side, malicious adversary party should not be able to affect randomness of R[i], i.e. even malicious adversary should not be able to generate d[m] to get specific R.
Looks like I can achieve this by simply hashing all d[i] values in predictable order. For instance sort d[i] and calculate hash of "well-known-secure-prefix" + d[1..N] + "well-known-secure-suffix".
Am I missing anything?