Great concept but do your research before buying This review relates specifically to the Yubikey 5Ci and the iPhone 14pro using IOS 17.1 in the UK. The 5Ci key doesn’t not have the NFC facility (contactless connection) therefore it has to be inserted into the lightening port. However it will not connect unless the case is removed before insertion. I appreciate cases vary but mine is a standard apple purchased case. (Rim thickness 1 or 2 mm!) Quite frankly in my view the inability to use NFC or the lightening port without removing the case renders the key impractical. This is not made clear when purchasing the key. Even if this is acceptable to you it seems that most financial / bank apps in the UK do not support the concept of the key yet. If you are inclined to buy the key it’s worth checking before hand that the services you wish to use support the Yubikey I purchased them (you need two) through Amazon and was given a refund. Yubikey were helpful up to a point but their support links are complex and cover a multitude of keys and devices. The concept is good perhaps things will improve.

Yubico's prompt refund I have a higher import duty issue with UPS carrier for an Yubico order and requested them to cancel after 5/6 days. They cancelled and refunded promptly.

Using Yubikey introduces the risk of the rightful owner of account is prevented access. It is a problem that Yubikeys cannot be duplicated for backup. They are so secure that even the owner of an account can be locked out, lol. That's not good. In case of lost key or hardware malfunction there is no way to access your account. Unfortunatly two different keys often cannot be registered for the same access. Using Yubikey introduces the risk of the rightful owner of account is prevented access.

Solid security keys I've owned a variety of YubiKeys since 2014, and I've always been very happy with them, I've only had to replace them either because I lost them or because I wanted some newer features, like USB-C or NFC. They seem to be the gold standard for security keys for a reason.

U2F Keys from Yubico I think having this type of security (U2F Key) and replacing other methods is just excellent. Combined with a password manager like Dashlane for example is just top notch and definitely safe from attacks. It's an open authentication standard that enables internet users to securely access any number of online services with one single security key instantly and with no drivers or client software needed. They come in many sizes fit to the users needs, obviously make sure to have a few spare.