How to validate @croupierbot is indeed incorruptible.

The @croupierbot, a simple bot created by @pibare claims to be incorruptible. This post will show how you can check it indeed is.

Here is an example of two subsequent responses by @croupierbot. The first post anounces a lottery draw at some point in the future.

Then in a second post, some time later, the winner is announced. What is importent here is the timeline.

• In the first post, a block number that does not exist yet is named and the lottery ticket numbers are assigned to contestants.
• In the second post, a link to the block and transaction the first post exists in is provided for you to check. As to validate the text of the post has not been tempered with. Further, the winner is announced.

As everything is recorded in the blockchain and visible to everyone through steemd.com, we can validate the timeline is correct and not tempered with. @croupierbot provides convenient links to steemd.com.

So how about the actual draw. For that, we need to look at the draw block witness signature. A huge number that was unknown when the contest was announced and the tickets were assigned.

If we go to the steemd.com link, we can copy the value of the witness signature and see if the draw was correct.

We use the copied witness signature and convert it to a huge integer in python. Now back to the first post. We had four tickets. If we use the modulus operator % , we get a winner for a four ticket lottery draw. So the winner here is ticket number one.