Craig Wright, the Australian computer scientist who claimed to be Satoshi Nakamoto -- the creator of bitcoin -- has backtracked on a pledge to provide more proof of his earlier claims . Wright says that he lacks the courage to face allegations. On May 1, Wright claimed that he was the creator of bitcoin , offering digital signature, signed using a private key that was thought to be held by Nakamoto. We later learned that the "proof" Wright offered was simply copied from an older transaction . At the time, Wright assured that he will be moving early bitcoins as "extraordinary evidence". On Thursday, Wright wrote in a blog post that he is "sorry," and that he cannot do this. He writes: