Clients, Protocol Update, and Maintenance
Ripple, Ethereum, Open Blockchain, and Bitcoin are currently open source, which allows any entity to build and release its own software client to interface with either systems. The official clients for Ripple, Ethereum, and Bitcoin are however maintained and regularly updated by the Ethereum foundation, the Bitcoin foundation, and Ripple Labs, respectively. Open Blockchain has been mainly an effort initiated by IBM, but now evolves with the help of the Hyperledger community.
Bitcoin and Ethereum clients can also run on resource-constrained devices such as mobile phones—owing to their support for simple payment verification. As far as we are aware, there exists no secure lightweight version of Ripple and Open Blockchain.
Note that all changes to the official Bitcoin client are publicly discussed in online forums, well justified, and voted among Bitcoin developers . This process is however less transparent in Ripple and Ethereum.
Ripple, Ethereum, Open Blockchain, and Bitcoin leverage completely decentralized protocols. Similar to Bitcoin, we argue that the current deployment of Ethereum and Ripple is also centralized.
Similar to Bitcoin, only a handful of entities can control the security of all Ethereum transactions. More specifically, a quick look at the distribution of computing power in Ethereum shows that currently the top three (centrally managed) mining pools control more than 55% of the computing power in the network. On the other hand, Open Blockchain aims for an enterprise deployment and credits control to the operator(s) of the validators.
Finally, in the case of Ripple, most validating servers are run by Ripple Labs at the time of writing. Although there are a few other servers that are run by external entities, the default list of validating servers for all clients points to the ones maintained by Ripple Labs. This also suggests that Ripple Labs can control the security of all transactions that occur in the Ripple system. Moreover, Ripple Labs and its founders retain a considerable fraction of XRPs; this represents the largest holdback of any cryptocurrency  and suggests that Ripple Labs can currently effectively control Ripple's economy. We contrast this to Bitcoin, where the current system deployment is not entirely decentralized, yet the entities that control the security of transactions, the protocol maintenance and update, and the creation of new coins are distinct . In Ripple, the same entity, Ripple Labs, controls the fate of the entire system.
In , it was shown that—although it has been introduced almost 2 years ago—Ripple is still far from being used as a trade platform. Ripple advertises a large number of active accounts . However, there is no strong evidence that users are active in Ripple; most accounts contain a small number of XRPs—which users could have received from one of the many giveaways organized by Ripple Labs . Moreover, although the number of transactions in Ripple seems to be considerably increasing over time, the number of actual payments in the system is only marginally increasing over time and is dominated by direct XRP payments. Finally, although there are a number of currency exchanges performed via Ripple— some of which deal with huge amounts—it is hard to tell whether those transactions have been actually concluded since the Ripple system has no way to enforce IOU transactions.