Over the last seven years we have been observing a tremendous growth of crypto-currencies such as Bitcoin and IOU credit networks such as Ripple. Their decentralized and pseudonymous nature, ability to perform transactions across the globe in a matter of seconds, and potential to monetize everything regardless of jurisdiction have been pivotal to their success so far. Despite some major hiccups, their market capitalization is increasing steadily over the years. It is now believed that, in the form of the blockchain technology and the internet of value, these concepts are here to stay. In this talk, I will first present some of our recent and ongoing efforts to improve the privacy of these inherently distributed systems. I will define the concept of peer-to-peer mixing, present an efficient P2P mixing protocol, and instantiate it in Bitcoin and Ripple. In the latter half of the talk, I will present an innovation application for these payment systems. In particular, I will present a novel Bitcoin-based smart contact for non-disclosure agreement (NDA) among mutually distrusting partners that monetarily penalizes malicious disclosures of the confidential documents.