What makes Ripple different from Bitcoin? Strictly speaking, Ripple isn't the name of the digital currency but of the decentralized payment network and protocol created and maintained by the eponymous Ripple Labs. Users of the Ripple system are able to transact in both cryptocurrency and regular fiat currency like the dollar without passing through a central exchange. XRP is the name of the native unit of exchange used in the Ripple network to facilitate conversion between different currency types.
However the number of takedowns and the fact that Tor relays were seized could also mean that the Tor network was attacked to reveal the location of those hidden services. "Over the past few years, researchers have discovered various attacks on the Tor network. We've implemented some defenses against these attacks (PDF), but these defenses do not solve all known issues and there may even be attacks unknown to us." Another possible Tor attack vector could be the Guard Discovery attack. The guard node is the only node in the whole network that knows the actual IP address of the hidden service so if the attacker manages to compromise the guard node or somehow obtain access to it, she can launch a traffic confirmation attack to learn the identity of the hidden service. "We've been discussing various solutions to the guard discovery attack for the past many months but it's not an easy problem to fix properly. Help and feedback on the proposed designs is appreciated."
According to Lewman, the task of hiding the location of low-latency web services is a very hard problem and we still don't know how to do it correctly. It seems that there are various issues that none of the current anonymous publishing designs have really solved. "In a way, it's even surprising that hidden services have survived so far. The attention they have received is minimal compared to their social value and compared to the size and determination of their adversaries."
Interested users can check out the screenshots and download the latest release. The project also accepts donations.
PayPal says it chose to integrate the third-party functionality directly in the PayPal Payments Hub because the aforementioned trio already offers its customers protections when dealing with the virtual currency. The company envisions anything that can be obtained digitally, such as video games and music, being sold in Bitcoin.