These days, simple passwords aren't good enough to secure your data. Hackers are too good, and security systems flawed. Longer complicated passwords created by generators like 1Password and Safari's iCloud Keychain can help, but the best way to lock down your accounts is to add extra authentication options.

What is two-factor authentication?

Two-factor authentication is the most prevalent way to secure your accounts: It asks you to authenticate that you are who you say you are by supplying not only your password, but a unique code supplied from your phone or an external app. It ensures that those accessing your accounts have access to your physical devices as well as your virtual passwords, and makes a simple password crack or social engineering hack a lot more insufficient when it comes to accessing your personal data.

Wait, does this mean I have to sign in with extra codes every single time I log in? Sounds tedious.

Nope: Two-factor authentication is designed for initial logins from new devices — specifically, the situation where someone might get ahold of your password from a multi-million password hack and try to log in from their device, and to prevent social engineering hacks, where intruders attempt to trick you (or your loved ones) into revealing your security questions or other personal information about your accounts. Two-factor authentication largely replaces your security questions: This not only helps you avoid needing to remember your random answers, but it also removes the risk of relying on potentially easy-to-find information.

Two-factor unfortunately can't prevent someone getting ahold of your accounts by accessing your physical device, but that's why Touch ID and strong Mac passwords are important.

Why is two-factor authentication so important?

Passwords are weak, broken, and by all accounts, outdated: Having to remember a random assortment of numbers, letters, and possibly (but not always) other characters can be tough on your memory and easy for attackers to compromise, especially when technology like Touch ID exists. Apps like 1Password can help with organizing and memorizing your passwords and even help you create super-long strings, but you're still reliant on a single password to keep you safe. Two-step/two-factor authentication requires two different keys to log you into your account, significantly amping up the level of difficulty for any would-be hackers to access your personal information.

What accounts can I set up with two-factor authentication?

Over the past few years, lots of web services and banks have hopped aboard the two-factor bandwagon — more than we can properly list. The folks over at Two Factor Auth, however, have kindly put together a master list of services that support two-factor or two-step authentication, along with links to how-to documents, what methods of two-factor authentication they support, and how to contact a service you use to request that they implement two-factor authentication.

How to secure your accounts with two-factor authentication

Here at iMore, we've put together a bunch of articles on some of the most popular services that support two-factor authentication — as well as the easiest ways to set it up — to help you keep your accounts safe and away from prying eyes.

What if I lose my phone (or have it stolen)?

One of the big fears with SMS or code-based two-factor authentication is the potential loss of your primary authentication device: If you don't have your phone, you can't get SMS messages, et cetera. Thankfully, most services offer recovery keys or special passcodes that can unlock your account in case you don't have access to your cell phone at the present moment. Make sure to write these down in a safe place; I use 1Password's secure notes feature for this, and also store a hard copy in my office.

Need more help with two-factor authentication?

Running into trouble setting up two-factor authentication? Have a question about turning two-factor on for your favorite service? The iMore Forums are a great place to get advice and help from other members of our community; you can also ask a question in our new Q&A forum and we'll get back to you as soon as we can.