Overstock sold its first cryptobond, the cryptography team at Blockstream unveiled its first prototype sidechain and more top stories for June 9. Overstock Sells World's First Cryptosecurity Overstock has become the first company to solicit qualified institutional buyers in a digital corporate bond which will trade using blockchain technology. CEO Patrick Byrne purchased the world's first cryptobond for US$500,000. The pioneering development is part of the company's larger cryptofinance initiative known as Medici, on which Overstock expects to sell a total of US$25 million in digital bonds. Overstock CEO Patrick Byrne said: "The cryptorevolution has arrived on Wall Street [...] …