Securing a text file might be more convenient for some people than securing an image file, although using the text code to set up a new phone or tablet likely won't be as convenient as using a QR code. It implements multi-factor authentication services using the time-based one-time password (TOTP specified in RFC 6238) and HMAC-based one-time password (HOTP specified in RFC 4226), for authenticating users of software applications. As an alternative to (or in addition to) saving a screenshot of the QR code you can ask for the text code and save that. Google Authenticator is a software-based authenticator by Google. Most sites that give you a TOTP QR code have an option to get the code in text. If you want to implement this yourself (which I can highly recommend if you are doing this just for fun) you can use the following HMAC implementations that are already part of : HMACSHA1 (default), HMACSHA256, HMACSHA512 and HMACMD5. To add a TOTP device later view the screenshot and scan the QR code. When the site gives you the QR code, take a screenshot and save that in some secure fashion. If you don't have all your devices available at the same time, or you want to allow for the possibility of adding a new device later, you can simply save the QR code. That way I'm covered if one of the apps stops being supported). (Actually, I scan it twice on each device, using two different TOTP apps. Für das TOTP-Verfahren benötigen Sie eine Authentifizierungs-App auf Ihrem Smartphone oder Computer. The simplest case, applicable if you have access to more than one device that supports generating TOTP codes at the time you are setting up TOTP for a given site, is to simply scan the site's QR code on all the devices.Į.g., when I create an account at a site that uses TOTP I scan the QR code on both my phone and my tablet. Yeah, bridging convenience and security is a long standing nightmare of a problem to solve. That also means that you should not have your password manager on the phone, or at least only have a separate one: ideally, password managers would integrate between desktops and mobile devices to pass short-lived access to passwords for Oauth/OpenID Connect auth instead. Physical separation of the two authentication factors, thus, matters. Making it not a "second" anything: it's akin to using two passwords for log in to a single site and keeping them in the same place. You are still protected from your password hash being stolen from the target website, decrypted and then used for log-in, but if password hashes were accessed, potentially a bunch of other stuff that you'd care about is too, so that's a somewhat moot point.īut someone stealing your laptop and getting access to your password manager gets access to your 2FA too. If your password manager has control of both your password and your "2nd" factor auth, it defeats the purpose of it being a 2nd factor.
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