Is it possible to have a cross-ledger identity management between hyperledger fabric and indy?
Is it possible to communicate between Hyperledger Fabric and Hyperledger Indy?
Can I read the data from Fabric and store it in Indy and vice-versa? My idea is to use Indy to authenticate identities and use Fabric to store data through chaincodes using the communicated credentials. Is Quilt the tool for it?
Hyperledger Indy is a decentralised identity system, while Hyperledger Fabric is a general purpose decentralised ledger that can be adapted for a variety of use cases. You wish to use Indy for your systems authentication purposes which itself runs on Fabric.
Consider Hyperledger Indy as an independent registry. The ledger is used for storing the DID's and claims, and can be deployed locally or you can also make use of the sovrin testnet. For testing, you can start a local pool of Indy nodes. Follow the getting started guide and check out the roles section. This will give you an idea on how to bootstrap your Indy network.
Once you are done deploying the Indy pool, the procedure from the end of Fabric is quite simple. Once your chaincode is invoked, it can make the appropriate authentication or authorisation calls to your Indy pool using the API provided by Indy-SDK. So for example when you invoke the chaincode for creating a new channel in Fabric, insert calls to the Indy pool to verify the identity of the participants.
Alternatively, Indy states the use of agents which will facilitate all the process handling for a user on the Indy pool, they have provided a reference implementation for the same. The agents just act as intermediateries, so regardless of what technology your system is deployed on, you can make calls to the agent for authentication or authorisation purposes.
Currently, there is not much progress has been made in facilitating inter ledger interaction between Hyperledger Indy and Fabric.
If you want to have API level integration from Indy and Fabric, you can consume Hyperledger Aries API for Issuing, Verifying, and revoking credentials from Fabric node SDK but mind it, this is API level integration of one SDK with another, not the ledger to ledger.
I know that there is work to make fabric-based Verified.ME compatible with Indy. Although I don't see much related activity on their github repo.
You may want to look into the newly incubating Hyperledger Ursa:
Ursa includes the Hyperledger Indy-Crypto code base that is the building block for anonymous credentials, the verifiable credentials protocol, in indy-sdk used by the Sovrin Network. Mike Lodder, the Security Maven for the Sovrin Foundation, has been doing a lot of work to ensure both Indy and others can make use of the library. We are hopeful the shared library will help other platforms better incorporate and use ZKP-based credentials and leverage Sovrin for their identity component. (From Sovrin Telegram)
There is also an implementation of IDEMix for Fabric which is the foundations of ZKP for INDY, I don't know if this helps inter-operability with Indy, but its a good lead.
While none of that is a direct answer, since the idea is to create a decentralized identity layer for the internet, all parties involved with identity will need to co-operate for that ideal to be realized.
