Calypso & DARCs
As soon as different data owners who don’t trust each other want to share data, a blockchain can bring the necessary trust between the different partners. However, first generation blockchains couldn’t handle sensitive data, as every node has the full view of all data. The OmniLedger / Calypso blockchain from Prof. Bryan Ford’s lab at EPFL enables data owners to share their data in an encrypted way and to maintain control over who has access to which data. Using a blockchain means that there is no single point of failure which would allow to access the documents in a fraudulent manner.
Another challenge when sharing data is who has access to which data. In practice this means who manages the access rights to your data. At all times you will be able to trace who accessed the data. As the access to your data is based on blockchain technology, the audit trail is immutable, so that misbehaving users can be held accountable.
The challenge with decryption is that one compromised keypair can lead to the decryption of all stored data. This is why Calypso uses multiple decentralized keypairs to secure the data. An attacker must get access to all keypairs before he can fraudulently decrypt the data. At C4DT we run a public installation of the OmniLedger blockchain and use it for access control to our website and chat system.