Netgear has warned customers that they have seen "suspicious activity" on user accounts associated with their Arlo security cameras. The company is very clear in saying they don't believe their systems have been breached. Rather, investigations suggest attackers may be using credentials obtained from other breaches and using those to attempt to gain unauthorised access to Arlo accounts. This is an object lesson in why you should use a unique password for every account and, preferably, use two-factor authentication on everything.

Two-factor authentication is one of the most important ways to protect your accounts. However, recently some authentication methods like SMS have come under fire for being vulnerable to hackers, which defeats the point of "something you know and something you have". We decided to look at the most common methods and rank them by how secure they really are.

Dear Lifehacker, My work wants me to enable two-factor authentication on my phone, but it seems risky. What happens if I lose my phone? Will I lose my entire account? And if I change phones, how do I move the authenticator to a new device?

Instagram reportedly started to roll out two-factor authentication yesterday, so accounts will be more secure and less prone to hacker attacks.

Using two-factor authentication via your phone helps protect your online accounts, but having to type in an authorisation code as well as a password can feel like a hassle. Google is introducing a new hardware key that lets you log into Google via Chrome and then authenticate yourself by clicking on the key -- no code required.

Two-factor authentication is one of the most important security features you can enable. We've had it on Apple IDs for a while, but it didn't work with all Apple services and apps. Today, Apple enabled the feature for iMessage and FaceTime.

I want my email and the rest of my digital life to be secure, so I like the idea of two-factor authentication. The problem is I travel a lot. When I am in Europe or the US, I don't use my Australian phone because I don't want to pay for roaming, and because I may be away for months at a time.

We love two-factor authentication, and we love services that make our text messages accessible from our computers. However, if you don't want anyone else -- a snooping spouse, child, parent, or most importantly, a laptop thief -- getting hold of your private information, you might want to alter how you use two-factor authentication.

Google has already been pretty great about supporting two-factor authentication. Now, the company is adding another option: authentication with a secure USB key.

Two-factor authentication is one of the most important things you can do to protect yourself against getting your accounts hacked, and you should enable it now if you haven't already. Authy is our favourite two-factor app on the block.

Two-factor authentication is one of the most important things you can do to protect yourself against getting your accounts hacked, and you should enable it now if you haven't already. Authy is our favourite two-factor app on the block.

Whether your files are stored on Dropbox, iCloud or Mega, they could do with a little more security. It's impossible to make them "hack proof", but there are a few steps you can take to make your data as secure as possible -- and still convenient to access. Let's walk through those steps.

iCloud hasn't exactly had the best week. You've probably heard that you should enable two-factor authentication on your Apple account (among others) to protect yourself from hackers, but be forewarned: two-factor authentication doesn't protect your iCloud backups or photos.

Apple is bringing two-factor authentication to its iCloud.com website and apps, which should make use the web-based versions of its services more secure.

Dear Lifehacker, I am quite security-conscious when it comes to online accounts and use strong passwords via LastPass and two-factor authentication wherever possible via SMS. However, I will be travelling overseas soon, and getting a new SIM card and number. How can I keep my accounts secure while travelling and not need to receive text messages?

Dear Lifehacker, I have an online savings account with an Australian bank that uses SMS codes for verification and login. However, it only allows Australian mobile numbers. I find this very restrictive: what if I travel overseas but don't want to activate global roaming? Is there any way I can work around this?

Two-factor authentication is critical for protecting your online accounts, but sadly, not every site supports it. TwoFactorAuth.org highlights all the sites that do or do not support two-factor authentication.

Hi Lifehacker, I use two-factor authentication everywhere I can. Most times I'm accessing one of my online accounts I do so on my PC, and my smartphone is the second factor. But as more and more gets done on smartphones I'm wondering how it will still be relevant to have two-factor protection. What's the point of having two-factor authentication if the second factor is the same device?

Back in April, Microsoft added two-factor authentication to Microsoft accounts. That service has now been enhanced with recovery codes to use if you lose the two-factor device, as well as improved tracking of recent login activity.