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When it comes to security keys, it's important to find ones that work with various hardware, apps, and services. One of the best security keys on the market, the Yubico YubiKey 5Ci, checks all the boxes when it comes to protecting your data, and here are the many reasons why.

The company's first hardware authentication device with an Apple Lightning adapter, the YubiKey 5Ci, is a terrific choice for iPhone owners and those with supported iPads. If you don't own one of those devices, including the iPhone 14, that's okay; the device also supports USB-C with its dual connectors. This means you can use it on unlimited devices, big and small.

The YubiKey 5Ci is designed to add an extra layer of security for authentication once you log into an account with a username and password---the key works with various authentication protocols and operating systems for business and personal use.

Quick Overview of Two-Factor Authentication

Two-factor authentication, or 2FA, has existed for many years and comes in many forms. It's a security process that requires you to provide two different authentication factors for verification purposes, usually when logging into a new device for the first time. Doing so can better protect your credentials and the resources you wish to access.

Before 2FA, a single-factor authentication (SFA), such as a password, protected most online data. Under 2FA, passwords (or passcodes) remain the primary authentication factor. For the second factor, you have a choice of options. First, there are security tokens, which a product like the YubiKey 5Ci provides. There are also biometric tools, such as fingerprints and facial scans.

Related: Here's Why You Should Use Two-Factor Authentication (2FA)

How the Yubikey 5Ci Works

If you're new to using security keys, expect to experience a modest learning curve. It's not that setting up keys for your favorite apps is challenging to do. Rather, the process for each app is slightly different than the next. This can add some confusion, especially when activating two-factor authentication in the first place. For example, turning on two-factor authentication on Twitter differs significantly from what you must do on Instagram and other social networking sites.

In most cases, you can set up your YubiKey security key on desktop and mobile. On the former, the process feels a bit easier, if only because computer displays are larger. However, developers have improved mobile setup considerably in recent years---it's about time---so the YubiKey 5Ci works with any device that supports USB-C and Apple Lightning with very few steps required.

To start on desktop or mobile, you must first turn on two-factor authentication for a given service. You can normally find the tool under the app's or account's settings page. Once two-factor authentication is activated, you'll need to select the option for security keys. Next, you'll be asked to attach your security key to your computer or mobile device. Then, for the YubiKey 5Ci to work, you must tap both raised metal modes simultaneously (more on this below). Once the app confirms the key, you're done. Yes, it's as simple as this.

If you no longer want to use the security key with a service, you can go back into its settings and remove it as a tool.

About Spare Keys

Most suggest owning two security keys, a primary and a spare. With two (or more), you're less likely to lose access to critical accounts---assuming you set up the service on both keys. Once you set up your keys, place one in a secure place, such as a file cabinet or safe. You'll be glad that you did.

The 5Ci Is All About Mobile

A person holding the Yubico Yubikey 5CI over an iPhone
Hannah Stryker / How-To Geek
  • Dimensions: 0.47 x 1.59 x 0.2in (12 x 40.3 x 5mm)
  • Weight: 3g (0.11oz)

As noted above, the YubiKey 5Ci is unique because it includes two connectors: one for Apple Lightning and another for USB-C. However, having two connectors will cost you, as the YubiKey 5Ci costs slightly more than other YubiKey 5 series keys. And yet, you'll also get a smaller device than some of the others. It's durable, with an injected molded frame and reinforced fiberglass.

Measuring 12 by 40.3 by 5mm and weighing just 3 grams, the YubiKey 5Ci features black plastic with a metal center hole to connect it to a key ring. You'll notice two raised metal nodes in the middle of the device. You'll need to tap these nodes each time to complete the verification process. No physical movement occurs when tapping, but don't worry, that's intended.

One issue with the YubiKey 5Ci when it was first released was the lack of compatible USB-C-supported devices on the market. These devices are much more than commonplace now and have become the mobile standard in Europe and other locations worldwide. One issue you may have is that the YubiKey 5Ci doesn't support NFC, unlike other YubiKey 5 series keys, including two of the best security keys on the market.

Compatibility: Works With Almost Everything

The Yubico Yubikey 5CI laying on a notebook
Hannah Stryker / How-To Geek

The YubiKey uses the Lightning connector on compatible iPhones and iPad. Likewise, USB-C will work on compatible Macs and iPads. Once you register the security key on one Apple device, it will be recognized on any other that uses the same Apple ID. Besides Apple products, the YubiKey 5Ci works with Android, ChromeOS, Windows, and Linux.

You can use your YubiKey 5Ci security key with various online apps, from familiar ones to those more obscure. Among the companies and services that work with YubiKey keys include Microsoft, Google, Amazon, Reddit, Twitter, Salesforce, Cloudflare, Coinbase, 1Password, and many more. In addition, the keys work across various categories such as finance, cyber currency, cloud, retail, etc.

The YubiKey supports multiple authentication protocols, including WebAuthn/FIDO2, FIDO U2F, one-time password (OTP), OpenPGP 3, and more on legacy and modern applications.

Should You Buy the Yubico YubiKey 5Ci?

If you're primarily going to use your 2fa security key on a Lightning-supported device, such as a compatible iPhone or iPad, the Yubico YubiKey 5Ci is almost certainly the choice for you. With USB-C and Lightning compatibility, the key provides more flexibility than other keys with only one connector, although you will pay extra. If you expect only to use the security key on USB-C compatible devices, get another YubiKey 5 version, such as the Yubico YubiKey 5C NFC. This security key offers USB-C and NFC for a little bit less (plus, the NFC portion works with the iPhone 6 and newer).

Overall, the YubiKey 5Ci is a terrific device with excellent compatibility and ease of use.

Yubico-Yubikey-5Ci-on-a-white-background-1
Yubico YubiKey 5Ci

Pros
  • Ease of use
  • Compatibility
  • Solid product
Cons
  • No NFC
  • Expensive compared to others
  • Might be better to go with another Yubico option