I just tried to use unowallet. It seem that the private key is somehow encoded into the url. Isn't it some known type of representation? Wouldn't it be possible to create an url for my private key?
Or maybe its just the seed of the bitcoin address generator.
My only observation is that it is not a base58 because there are 'l' and 'O's, it may not be base64 because it does have bad number of characters (but maybe '=' are ommited).
Private key: 5JWXyvz2DcEKQFm7pa6j8Gp1M5A8cgNhx4F2ZjM2R14MHy3D2NQ