isabella232 / demo_18_master

Repository for creating docker images for the master blockchain workshop in Amsterdam

ByzCoin demo for Master Blockchain Layer 1

For the Master Blockchain Layer 1 Solution Workshop in Amsterdam in '18 we created a demo for participants to use our conodes to create a simple byzcoin setup.

This gives a first insight into the cothority framework and the blockchain implementation of the DEDIS lab called ByzCoin.

The presenter's laptop runs 4 + 1 conodes that build a byzcoin cothority and must be accessible by the other participants.

The following exercises are implemented:

1. Get the status of the presenter's conodes
2. Create a collective signature using the presenter's conodes
3. Start up a conode on the participants' laptop
4. Join the main byzcoin using the participants' conodes
5. Create and transfer coins
6. Inspect some of the data structures (proof + instance)

Preparing the demo

Go-environment

We suppose you have a working go-environment using go-version 1.10 or above. You can check it with this command:

go version

Then you need to download the cothority-package and get the right version. This step has to be done only once.

make fetch_cothority

IP addresses

Whenever you change IP addresses for the presenter's laptop, you will have to run the following command and then re-create the docker-images! On my Mac I created an additional WiFi in my network preferences to fit the IP address of the demo-place, so that I can test it at home or in the office.

make update-ip

Docker-images

To create the docker images, you first need to adjust the settings for your demo in the Makefile. Three variables can be adjusted:

• IP - represents the IP address of the presenter's laptop. It must be accessible by all participants' laptops
• DOCKER_PREFIX - is used when creating docker images. The first part must be accessible by your account of https://hub.docker.com that is linked in your computer using docker login
• VERSION - when trying it out, be sure to increment the version whenever your participants downloaded a docker image

Then you need to run

make

to create the binary distributions for the presenter and the participants.

Distributing the demo

The simplest way to distribute the docker images is using docker-hub. Set up the system using docker login if you already have a username/password, else go to https://hub.docker.com and create an account.

Once your docker installation is correctly set up to being able to connect to the docker-hub, type:

make docker_push

and it will send the docker-images to docker-hub.

Starting the demo

The demo has two parts: the conodes started ont he presenter's laptop, and a set of webpages for the students to access directly from the presenter's laptop.

Starting the conodes

Now you're ready to start the nodes on your computer. Be sure that all firewalls installed allow incoming connections on the ports 7770-7781. Then type the following command:

make run-admin

This starts the 5 admin-conodes. 4 of them are configured to build a byzcoin-blockchain, while 1 is idle and waiting for you to activate it.

Starting the webpage

To start the webpages, run the following command:

make run-www

This supposes that python is installed and can run a local webserver for the following three services:

• http://localhost:8000/ - for the general overview of the demo
• http://localhost:9001/p/demo - an etherpad instance to have a self-hosted environment without the need for a google doc
• http://localhost:8000/student_18_explorer/dist - a simple blockchain explorer

When presenting the demo to students, the IPs will have to be adjusted.

Testing the demo

Follow the instructions in the presentation and check that everything is running correctly. There is a local copy of the presentation in slides.pdf. The google-doc is available here:

Google presentation

Adding nodes to byzcoin

In step 4 of the demo, you will have to add the conodes of the students to the ledger. This needs to be done in the cothority started by

make run-cothority

This command runs the cothority on the presenter's laptop, but it also links to the private key created during the byzcoin-setup, which means, that the presenter has admin-rights to the byzcoin, while the students can only query byzcoin up to step 5, where they get access to their coins.

In the presenter's cothority-docker, the following command can be used to add a conode:

bc_add "
PASTE PUBLIC NODE INFO HERE
"

The opening " and closing " are important, so that the command correctly recognizes the entry. An example would be:

bc_add "
  Address = "tls://192.168.0.232:7772"
  Suite = "Ed25519"
  Public = "6b225f7555d0d23b12bcc20f92c05858d8a2796050b592007465ee5cdb5b2ce1"
  Description = "Conode_1"
"

Notice the missing [[servers]] which will be added automatically by the bc_add script.

Comments / Feedback

If you use this demo, please leave some feedback to Linus Gasser - even if it's just to say something like: "did a demo with 10 people, and it crashed only once".