A Witness is a Gulden user that has locked his or her Gulden (min. 5000 Gulden) for a certain period of time (min. 1 Month) and receives interest from the system itself. A Witness is anonymous and is selected at random.
The miner needs a Witness to verify the block before it becomes valid. Witnesses can only verify blocks that play according to the rules, so a miner has to share a block immediately to avoid losing money. This prevents miners from misbehaving.
The code is accessible to everyone and can be verified by anyone. Contributions from experienced developers are welcomed. You can write code, solve bugs, discuss code or help us develop Gulden.