Reuters / Dado Ruvic Bitcoin's decentralized nature has been one of its biggest selling points, but imperfect storage methods have made millions of the tokens inaccessible.About 20% of the 18.5 million bitcoin in existence - worth about $140 billion - is estimated to be lost or stuck in locked-off digital wallets, The New York Times reported on Tuesday.For now, those coins are effectively trapped behind incredibly complex encryption and forgotten passwords.Solutions can still come from cryptocurrency reform, Jimmy Nguyen, president of the Bitcoin Association, told Business Insider.Emergency mechanisms that can recover bitcoin in the event of forgotten wallet passwords or estate transfers can make it a more "open and user-friendly" cryptocurrency, Nguyen said.Sign up here our daily newsletter, 10 Things Before the Opening Bell. Cryptocurrency enthusiasts praise bitcoin's decentralized nature. Yet the imperfect methods used to secure the digital tokens are pulling millions of bitcoin out of circulation with little hope of recovery. Bitcoin owners hold private keys necessary for spending or moving tokens. These keys exist as complex strings of data and are often stored in protected digital wallets. Those wallets are then typically protected with passwords or authentication measures. While their complexities allow owners to more securely store their bitcoin, losing ...read more...