Sunsetting OmniLedger from C4DT Market

The C4DT supports some libraries and applications from our labs through the Market. Code in the Market is supported for two years by C4DT. After that we evaluate the situation and either commit to two more years, or remove the code from the Market. The first code in the Market was OmniLedger, added in April 2020. It is a next-generation blockchain and has been developed by DEDIS, Professor Bryan Ford’s laboratory.

As OmniLedger development by DEDIS has been stopped 2 years ago and as it is not actively used by any C4DT partner and because we reach the end of these two years, it was decided to sunset this application. If you want to know what we did with Omniledger during this time, and what the end of support means for you, read on.

What is OmniLedger?

Omniledger is a blockchain that has been developed by DEDIS, Professor Bryan Ford’s laboratory. It is based on a number of published and peer-reviewed papers regarding high performance blockchains:

  • Collective Signatures in 2016 – verify in O(1) the collective acceptance of data
  • Byzcoin in 2016 – speed up transactions in a blockchain
  • Chainiac in 2017 – optimize the links between blocks to traverse a blockchain in few steps
  • Omniledger in 2018 – scale-out transaction speed: increase the speed with more servers
  • Calypso in 2021 – hide secrets in plain sight in a blockchain

All these papers have been implemented with a library developed in Bryan Ford’s lab, onet, and collected under the name cothority, for “collective authority”.

OmniLedger Demonstrator

The demonstrator based on this code is split in two parts: the nodes and the frontends. The nodes include the following functionality from the above papers:

  • Two protocols for the consensus algorithm: byzcoinX and blsCoSi
  • An account-based smart contract system based on Ethereum, including an EVM interpreter, based on the Chainiac system
  • An implementation of Calypso, both the access-control and the secret-management part

Together with DEDIS we developed various frontends for these nodes:

  • E-voting at EPFL, used in the EPFL school board elections between 2018 and 2022
  • Decentralized login system with decentralized access management, working with  WordPress and Matrix
  • Demonstrator of the Calypso system
  • Blockchain-viewer to inspect the blocks
  • Demonstrator of how to verify smart contracts using statical analysis tools

Hands-on Workshops

The C4DT is using the OmniLedger demonstrator to discuss with partners and to explain the blockchain technology to students. 

We did the first hands-on workshop for SICPA in 2020, to demonstrate private key encryption on the blockchain. The goal was to find a solution to recover private keys of a self-sovereign identity wallet. With a group of 8 software engineers from SICPA, we showed how the system works. In the first part we looked at the theory of threshold encryption and decryption. Then we used the OmniLedger demonstrator to actually store and retrieve messages on the blockchain itself, stored in an encrypted manner.

We also used the demonstrator for the “COM-402 Information Security and Privacy” course to explain how blockchains work. Using the demonstrator, the students signed up with their email and created transactions. Then they looked at the blockchain and searched for the transactions. In the end they understood the way a transaction is sent from the client to the blockchain, and how it is stored. This demonstration has been done for three classes now, and the fact that everything fits in the browser makes it very easy to use as a hands-on exercise.

Proof-of-Concept Projects

The OmniLedger project has seen a lot of development within the following proofs-of-concept:

  • ByzGen – this was the first client to develop the Calypso part of OmniLedger. Together with ByzGen we developed the first version of Calypso that was usable via an external API. They still use it in their current product
  • MedCo – funded by the PHRT/SPHN, DEDIS developed a federated authorization scheme to access statistics on medical data
  • SunBioscience – through a grant from EIT Health, DEDIS developed an application around OmniLedger to handle consent management of patients
  • Odyssey – through an agreement with an industrial partner, DEDIS developed a proof-of-concept of a system for Auditable Sharing and Management of Sensitive Data Across Jurisdictions