In the question of the most secure wallets, GreenAddress will effortlessly top, or if not, then at least be among the top. They are not even sent to the server. This goes a long way to ensure total privacy. This means that if you use your email and mobile number as authenticators, you could still get access to your account even if you lose your email since the mobile number will still be usable as an authenticator on its own. Every visitor to Buy Bitcoin Worldwide should consult a professional financial advisor before engaging in such practices. If your main focus is on security, then you can go with GreenAddress.