With two-factor authentication we can access our sites with greater security than simply entering a username and password: in fact, at each access we will be sent a code via SMS to be used together with the credentials. If the SMS is late in arriving or is not received, we risk being out of our account! To avoid this we can replace the sending of SMS with an authentication system using a single-use code (OTP is going to One Time Password), generated securely through some apps.In this guide we will show you the best apps to generate OTPs for two-factor authentication, also explaining how to add the various accounts to control to the app. At the end of the guide we will be able to obtain our OTP codes without having to wait for the SMS, quickly and safely, using an app uniquely associated with our mobile device.
Enable two-factor authentication
Before we can use OTP codes, we will need to activate two-factor authentication on the site we want to protect with them. Among the most famous sites that accept the OTP codes generated by the apps for secure access we point out Amazon, LastPass, Microsoft, Google and Facebook, but there are hundreds of other sites that support this type of authentication. For each of these, the steps to follow are very similar to each other: we log in with the relevant account on the security page, enable two-factor authentication and choose to use an app generated code (also called App code, Token code, Authenticator app o Authentication app); at this point we will be offered a QR Code or a secret code, to be included in one of the apps that we will show you later in the article.
This code provided in the initial configuration phase it is essential to be able to use the OTP code correctly: in fact, the information contained within the QR Code or the secret code allows you to generate a different password every few seconds, even without an Internet connection. By configuring the app then we will be able to access our account every time simply by entering the code displayed at the moment (possibly before the associated timer "expires"). To complete the configuration, simply enter the OTP code generated by the app immediately, so as to communicate the correct configuration to the site.
TECHNICAL NOTE: how do the website and the app communicate and know that the code is always correct, even without an Internet connection? The explanation is quite simple: the QR Code or unique code used will "train" the app to generate gods pseudo-random specific codes, based on the algorithm created for us by the service. Since the algorithm of the site (associated only with our account) and that of the app are identical, the OTP code generated will always be identical, so the site will always know which code to "expect" at that precise moment.
This authentication method is very secure and difficult for hackers to intercept and for any attacker, given that to be able to violate it it is necessary to use the encrypted algorithm stored within the app. The apps themselves offer very simple additional security systems, such as unlocking with a fingerprint: whenever an OTP code is required, simply open the app, use the fingerprint and retrieve the specific OTP code for the site. we are accessing. In addition to the imprint, we can also set a PIN or password, so as to make access to the site even more difficult.
In case you lose your phone or app, let's make sure always activate an alternative two-factor authentication method (SMS, notification on the phone, call etc.), under penalty of being permanently out of the account (since it will look for an OTP code that we will no longer be able to generate).
If we want to deepen the discussion on two-factor authentication, we refer you to reading our dedicated guide -> Sites / apps where you can activate two-step password verification.
App to generate OTP
After seeing how to set up two-factor authentication, we'll show you the apps we can use to generate OTP codes. We remind you that these apps are suitable for all services that accept authentication via OTP: even if they will seem specific to a service, in reality allow you to manage all sites that support this type of authentication.LastPass Authenticator
One of the best apps to generate OTPs is definitely LastPass Authenticator, available free for Android and iOS.
LastPass Authenticator">With this app we will be able to quickly scan QR codes or secret codes to add compatible services, including of course LastPass.
Once all the services have been added, we will have the numeric codes available on the same page, with a timer well displayed on the side of each site on which we have associated this type of authentication. To increase the security level of these codes, we can use a PIN, fingerprint or FaceID to quickly unlock the app.
This app works even if we have no account or password saved on LastPass, a famous service for securely storing access passwords for our sites online, as seen in the dedicated article -> Store passwords and logins to websites in a safe and secure way.
Microsoft Authenticator
Another app that we can use for authentication via OTP code is Microsoft Authenticator, available free for Android and iOS.
Microsoft Authenticator<">This app allows you to immediately associate all the services that work with OTP codes, showing the code generated at the moment for a particular service in a clear and unambiguous way. Also in this case we can use fingerprints, Face ID or a simple PIN in order to protect the access to the codes for our accounts. Absolutely to try as an alternative to the solution offered by LastPass (which I recommend trying anyway).
Google Authenticator
The Google app is one of the best for generating temporary OTP codes to use when two-factor authentication is enabled.For this app I had dedicated a separate guide on how to use Google Authenticator to secure web accounts
Authy
The last app I recommend you try for OTP authentication is Authy, also available for free for Android and iOS.
Authy">With a clear and easy-to-use interface, this app allows you to quickly associate QR codes and secret codes of various services compatible with OTP authentication, with the ability to copy the OTP generated also to the smartphone clipboard, so as to use them to access the apps of the services on which we have activated the authentication.
As for the other apps, it offers the possibility to protect access to codes with PIN, fingerprint and Face ID, so as to keep intruders away.
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Best apps to generate OTP, for secure access to sites
