Corda
Corda is not a blockchain by definition because it does not use blocks for batching transactions. Still, it is a distributed ledger, and provides all benefits that a blockchain can. Traditional blockchain solutions have the concept of transactions that are bundled together in a block, and each block is linked back cryptographically to its parent block, providing an immutable record of transactions. This is not the case with Corda.
Corda has been designed entirely from scratch with a new model for providing all blockchain benefits, but without a traditional blockchain with blocks. It was developed initially for the financial industry to solve issues arising from each organization managing its own local ledgers. This means that each organization has its own "view of truth." This situation often leads to contradictions and operational risk. Moreover, data is also duplicated at each organization, which results in an increased cost of managing individual infrastructures...