I am working through the implementation of A Distributed Private-Key Generator for Identity-Based Cryptography. In the paper (Figure 1, page 8) the validation of a share by a node says that once validated the node sends a confirmation or accusation signature to the bulletin board (step 2 below):
It mentions these signatures later on in the process as well but does not mention how to generate them (they are short ints in the implementation section 7.1)
Is the confirmation or accusation signature a cryptographic signature or simply and indicator that the node could verify its share?
- If it is simply an indicator then how can the bulletin board know that the node is being honest?
- If they are cryptographic signatures how are they generated? It doesn't appear that the bulletin board ever knows the public key for that node so how can they be validated?