It’s a bit of math, split into two pieces.
You hand out one piece, that’s the public key. It’s tiny and simple.
You keep the other piece, that’s the private key. It’s long and complex.
The public key can scramble data that only the large piece can unscramble.
The private key can create a piece of data that only the public key can verify.
In practice, these keys can be kept in a database or a file, and they can be held in a hardware security key (yubi/fido). They can be stored on your phone, in Bitwarden, and just about anywhere that keeps passwords, they’re really just a few thousand bytes of data.
In many cases, You can store them in your phone’s private password storage, then when you log into a website, it will trigger a popup on your phone to authorize your login, so you don’t even have to keep them on the computer you’re using to access the secured site. Most of the implementations require you to have a biometric component. You need to face scan, fingerprint scan, or, worst case, use a password to unlock/verify the passkey on the device.
The upside here is that the keys are unique to every site. The public key is completely safe to hand out to everyone, it can’t be reverse engineered. This means that websites can’t leak your login credentials in any meaningful way. edit: Also since you’re using math to change a piece of data, it’s impervious to a replay attack and the communication even unencrypted would be reasonably safe even if someone was actively reading it.
As far as storing for loss, I’d consider regenerating them. I prefer using a password manager that stores them, that way my phone/computers all have access to the same keys.
My voice is my passport, verify me.
A passkey is a super general term. It’s usually something you can store in a file (because you can store any data in a file) though sometimes it may have a hardware element. You can probably save your passkey in a file and you certainly can copy it onto a USB drive.
You can also save passkeys into password managers which is what I personally do so (coupled with a syncing script) I can access it from any of my devices.
That makes it sound like it’s a password. If a passkey can be saved in a password manager, can it be memorized or written down? What makes a passkey different than a password? Or are they just two ways of saying the same thing? Is it a really long password that makes you dread having to type it in, or even worse, enter it in with a virtual keyboard with a remote with arrow buttons?
Imagine a password about 80000 characters long.
No, the cryptographic keys used in passkey are not just very long passwords. In face they are not so long. Typical keys generated with ed25519 are 60 characters long.
Ah, i can’t find the thing i read now so I’ll assume you’re right.
Everything in a computer is data - passwords are no different from novels and you could use War and Peace as your password as long as you hated whatever system needed to check it.
Passkey is usually used to describe a password you keep in a file usually with a public/private pairing though, with everything computer, this is only the general form and description.
I mentioned putting it in a password manager because, as mentioned, it’s just a string of text… if you want you can put the full executable bundle for Starcraft2 in your password manager - most have trivial ways to copy in whole files but, again, it’s just data.
As far as I understand it, passkey is a password replacement and a protocol built on top of FIDO.
The intention is to replace passwords by cryptographic keys (asymmetric encryption). These keys come in pairs always:
- a private key: secret and only ever known to you
- a public key: given to the service you want to authenticate to. This key can also be seen as a lock that can only be open by the matching private key.
The keys are nothing more than text and they can very well be stored in files on a USB drive, copied, transferre, deleted, etc.
But passkey also defines the process to exchange and store the keys in a secure manner. Therefore in practice you will always use a password manager and maybe also some specific hardware, to automatically hand the key exchange and secure storage of all the different keys your have for all of the different services you registered to.
An article I read recently suggested that storing passkeys with Google, Apple, and M$ didn’t have interoperability. Like you need a Mac/iPhone or PC/Android to make it work. Is this true? Can I store a passkey in a platform agnostic way?
Aside from platform agnostic password managers having support for it as a commenter below pointed out you can also save it on a physical “hardware security key” (e.g. yubikey). Technically this should be the best option as there is no way for anyone to steal your passkeys unless they physically take apart your hardware key (and there’s even keys that have additional protections that make it impossible to take apart without destroying it).
However every single platform really pushes people towards using their own solution. So only their solution is neatly integrated in their platform and also preselected when you save a passkey. But all in all those are rather small hurdles for the security a hardware key gives.
If you’re talking about what Google or Microsoft offer as a login tool, it’s basically a file hidden on your physical PC so when you attempt to login to a service that wants it, the service gets a password from you and the passkey from your actual device to authenticate you.
For example, I have passkey enabled on my windows PC that my Google account has a passkey in. Anytime I access the built in password manager in chrome, Windows now gives me a pop up for a PIN number, and then windows will authenticate on my behalf with the hidden passkey.
If I need to access my password manager from my phone or another computer, I have to use my Google password instead since my passkey isn’t on those physical devices.
I believe Microsoft stores your passkey files on your motherboards TPM module, but I could be wrong.
Basically dedicated 2FA hardware.
If you lose it, you’re fucked, end of story.
You do not need specific hardware to use passkey. For example you can use a password manager like Bitwarden and have your passkeys sync between multiple devices, including a good old regular computer.
Specific hardware car be use to secure how the passkeys are stored. For example, smartphones usually have a security chip that help s with storing encrypted data.
Your milage will vary with your corporate policies. You’re not wrong, but you’re not completely right.
I can’t just pick up any smartphone and install a passkey manager on it. It has to adhere to some specific hardware requirements (like a dedicated chip or instruction set on a CPU).
So yea, in standing by the 2fa dedicated hardware line. It’s easier than getting into the weeds on hardware device configuration.
