ECache

eCache is an anonymous, encrypted digital currency backed by gold, intended as an electronic version of banknotes. To preserve the anonymity and prevent it from being squelched by the government (as happened to eGold), it is conducted entirely via secure and anonymous protocols such as Tor, with no public-facing website. This makes it difficult for anybody outside of crypto-libertarian circles to find out about it in the first place. The name is confusingly similar to ecash, but it is entirely unrelated.

Links

 * Wikipedia article