Introduction to Blockchain Technology Programming
You can use C/C++, Python or Java for this project. You must include a detailed instruction on how to compile/execute your code in the submission.
For this project, you will implement a “modified” PoS-based voting algorithm. The original Casper FFG consists of two layers:
1. The bottom layer is the tree of transactions.
2. The top layer is the sub-tree of checkpoints extracted from the tree of transactions.
For the sake of simplicity, the following assumptions are made:
1. There are 10 validators in the system. The set of the validators are fixed. The deposits of the validators are given in the table below:
Validator ID
0
1
2
3
4
5
6
7
8
9
Deposit Amount
500
100
300
250
150
500
600
350
200
150
2. The checkpoint tree is already given.
3. The checkpoint tree is a full binary tree.
4. Each node/checkpoint in the checkpoint tree has a number associated with it. Given a node of number 𝑛, its left child is 2𝑛+1, and its right child is 2𝑛+2. The root node is labeled 0.
5. The length of the link contained in each vote is always 1. This means a validator cannot skip any checkpoint in its vote, i.e., the target of the link is either the left child or the right child of the source. (Note: in the real Casper FFG, a vote can skip some checkpoints. An example is given on page 27 of the slides, where link 𝑏! →𝑏" skips two checkpoints.)
6. For each vote, the probability of selecting the left child as the target is the same as the probability of selecting the right child.
7. If the sum of the deposits of the nodes voting for a link L exceeds 1/2 of the total deposit, L is the supermajority link. (Note: this is different from the 2/3 rule used in real Casper
FFG.)
In your program, starting from the genesis node, you will run the Proof-of-Stake (PoS)-based voting 10 rounds, which yields 10 supermajority links.
Output:
• The blockchain formed by the 10 supermajority links, which is a list of the node/checkpoint numbers; and
• The IDs of the validators who finalized each checkpoint.
