A practical and transparent method to sort

In this short post, I introduce a method that might interest readers from this blog. I present a practical method that randomly pick people without the need for a trustworthy third party. Before describing it in more details, I want to insist on its two main features.

The method is practical because it only requires a basic computer (a smartphone largely suffices). Computers cannot generate random numbers because they are deterministic, however they can produce long sequences of numbers that do not repeat themselves for a long time. If you don’t know how the computer generated sequence work it is difficult to predict the next outcome. The numbers in this sequence will constitute our set of random numbers.

How could we generate the set without a trustworthy party? A malevolent individual can let the computer run until they obtain the desired results. If you know the initial number of the sequence and how the sequence works the result becomes entirely deterministic. We call this number the seed and this number will entirely determine our set of random numbers. We use this property to generate an impossible to forge sorted list of members. But how do we pick this seed?

Our method uses a stock market index. This has two interesting properties, firstly it is impossible to predict (otherwise tell me so we can become rich fast :) and every market agrees on it. This guarantees true randomness. Secondly, everybody will be able to reproduce our sortition if they have the seed value, the member’s list and the script we used. This guarantees transparency and accessibility.

We will employ this method in our association (l’Association Française pour la Sortition) to constantly renew our board. I already wrote the code using the CAC40 index to perform this task, it is free, open-source and you can access it you can follow this link: https://framagit.org/PersonnePirate/sort.