Assignment

You are going to create your own Blockchain (just like in the video) with only one little difference. He uses an Array to store his Blockchain, you are simply going to do this making the Blockchain a List.

Differences will be;

Block object will need a pointer to next (and previous if implemented doubly which I recommend)

Your Block will NOT need an index

Your Block will NOT need a timestamp.

Blockchain Object will need a pointer to head and tail.

Blockchain will need to implement push (you should have this).

The key will be writing the isChainValid() function

You must use a 64 bit or greater Hash Function

For the output you will create a Blockchain that allows the user to input data and push that onto the end of the node. When the user does that the output should be the results of the isChainValid() function.

You will then create a Button that will invalidate the Blockchain by directly changing the content of the head. It should then output isChainValid() to show that isChainValid() works correctly.

Note: You do not need to implement the Proof of Work capability.

Please provide a screenshot of it working in jsfiddle with the html and javascript portion.