Iroha was contributed by Soramitsu, Hitachi, NTT Data, and Colu in September 2016. Iroha is aiming to build a library of reusable components that users can choose to run on their own Hyperledger-based distributed ledgers.
Iroha's primary goal is to complement other Hyperledger projects by providing reusable components written in C++ with an emphasis on mobile development. This project has also proposed a novel consensus algorithm called Sumeragi, which is a chain-based Byzantine fault tolerant consensus algorithm.
Various libraries have been proposed and are being worked on by Iroha, including but not limited to a digital signature library (ed25519), a SHA-3 hashing library, ...