C4DT is working on bringing software from the labs to the real world. As part of this effort, we’re working on implementing use-cases for OmniLedger. OmniLedger is a novel blockchain that offers several new features. For example it works as a decentralised login service. This means that there is no central service deciding on who has access or not. At C4DT we’re using this login service to give access to restricted resources to our partners. Currently we have the following resources protected with this login service:

  • C4DT partner login containing the archive of newsletters
  • Matrix chat service to interact with engineers and during workshops
  • Demonstrators: OmniLedger and Stainless, and soon Drynx

How to Use

Instead of a username and a password, you will receive an account and a private key. This private key will be stored in the browser of your device. Every time you want to log in to a protected resource, the browser will use this private key to prove you hold your account. It is also possible to add other devices to your account, like a smartphone, or another desktop computer.

Requesting an Account

To request an account, you need to contact info@c4dt.org. Ask for a new account and give your affiliation: the name of the partner, or the EPFL lab you’re working in. If you are eligible to receive an account, we will send you an activation link:

https://demo.c4dt.org/omniledger//register?ephemeral=c4d767e0fae6ac31efa1c31698442211980b20e912128112341ba99d85c2c4d7

Activating an Account

Clicking on this link will open the account in your browser. First you will have to confirm that you want to activate this account. Then the browser will create a private key to secure your account and write the corresponding public key to the blockchain. After that your account is ready.

Using your Account

Now you can do one of the following:

Losing your Account

It happens to the best: the browser crashes and removes the account. Your phone gets stolen with the account in it. Or a malfunction in the demonstrator destroys your account. Fear not! We built in a recovery algorithm, where we can restore your account and give you a new private key. It is based on DARCs, so more complicated recovery systems are also possible.

More Advanced Usage

There are two things that might be interesting to you: first, how to add more devices, secondly, peek into the blockchain as it is updated.

Add and Remove Devices

If you want to use your account on a second device, you need to create this yourself. Go to devices and click on Add Device. Then you need to add the name of the new device. Now the system creates a new private key, and stores the corresponding public key on the blockchain. Once this is done, you will be shown a QRCode and a link. You can either scan the QRCode with your phone, or copy the link and send it through email to your other desktop computer.

The link and the QRCode are only valid for one activation. If you want to add more devices, you need to click on Add Device a second time.

If you lose a device, you can click on Delete located to the right.

Be careful not to remove the recovery account, else we cannot help you recovering your account.

Peek Into the Blockchain

At the bottom of your account, you will find a very simple blockchain explorer. You can peek through the entries that are stored on the blockchain. As a starting point, you will find four blocks. Clicking on one of the blocks will show you the content of this block. Each block contains transactions that define a request to change the blockchain. In addition to this, you find also the links to previous and next blocks. For more details, you can have a look here: https://github.com/dedis/cothority/tree/master/byzcoin