JPMorgan’s distributed ledger project "Juno" was unveiled at the latest meeting of the Linux Foundation’s Hyperledger Project steering committee on March 3. The Project is exploring developing an open source blockchain.
At the meeting, JPMorgan Executive Director David Voell revealed that the bank has been working on Juno since September. The prototype was presented by Will Martino , one of the developers of the project.
Martino said the team had considered methods besides proof of work and proof of stake, and began Juno from a fork of the Haskell implementation of Tangaroa , a Byzantine Fault Tolerant implementation of the consensus algorithm Raft .
He mentioned that as Juno doesn’t require anonymous participation, this has been explicitly disabled. Use of Tangaroa also removes the need for mining.
Using the Raft protocol as a basis allows a cluster of servers to order messages and distribute them to the network. Within the network, election of a "Leader" ensures that consensus can be reached among the "Followers." Martino explained that as Juno requires only consensus on inputs and not outputs, slow nodes are less likely to slow down the whole system.
When messages transmitted within the network have been ordered and replicated, they are interpreted by a replicated state machine. Juno allows the Leader to feed an input into the state machine when an entry has been replicated by the majority of nodes.
Juno is making use of a language named Hopper in its replicated state machine in order to run smart contracts. The language is still in development. When complete, it is expected to be sequentially consistent, fully deterministic, completely serializable, and will include a measure of execution cost.
For the immutable ledger itself, the JPMorgan team has not gone for Bitcoin-style Merkle trees. Instead, they use a Tangaroa-style incrementally hashed log of entries. This essentially creates a […]
