I have a scenario in which one of n participants is to be assigned a positive value and all other participants a negative value.
The outcome of the draw is to be known only by the respective participant. Additionally, each participant has to have the possibility to disclose and proof their bitness (selected/not selected) at will.
One of the participants should be able to perform the drawing unbeknownst the outcome. That participant is not a trusted third party nor is one available. There can be put some trust into the participant to not peek into the memory of a program that performs the drawing, e.g. not actively trying to break the secrecy of the outcome.
Is there any established protocol or scheme that can accomplish this or can be made to accomplish this? If there isn't, what could be a cryptographically sound way to accomplish this?
