decrypt-otpauth-files VS tpm2-totp

I used OTP Auth.app (https://cooperrs.de/otpauth.html) for many a while years on iOS and then on macOS too.

Now I've mostly transitioned to using the built in OTP handling in Keychain. Every so often I find one I haven't migrated across yet.

Another option is HE's NetWork Tools iOS app, which also has an OTP Authenticator in it. I believe it's a lot less integrated though (I don't think it provides a browser plugin, for example).

Forget all the cloud-based Authenticators and use OTP Auth. https://cooperrs.de/otpauth.html

I have been using OTP Auth for a while. It doesn't get updated a lot but it's working fine.

https://cooperrs.de/otpauth.html

I do that using a separate app, (OTPAuth for iOS), and pretty much for the same reason.

OTP Auth Website

Good point. See also the developer's website: https://cooperrs.de/otpauth.html

Sure, that's a possibility. I believe it is developed by a single person. But the OTP Auth app allows you to export an encrypted backup that can be decrypted using an open source tool available here: https://github.com/CooperRS/decrypt-otpauth-files. Also, the OTP Auth app lets you view the original secrets (and display QR codes) used to create the TOTP entries. So it would be relatively easy to simply scan the QR codes with whatever new app you wanted to use in the future. In my book, that makes OTP Auth the safest option because I am guaranteed an easy way to migrate to a new app if I ever need to do so. ... Also, OTP Auth lets you have folders (in addition to searching), which is really helpful if you have a lot of 2FA accounts.

This is the best iOS answer. One of my most favorite apps. https://cooperrs.de/otpauth.html

OTP Auth. https://cooperrs.de/otpauth.html For iOS and macOS

You need a TPM 2.0 compatible CPU, but something like this sounds really excellent: https://github.com/tpm2-software/tpm2-totp

This means your laptop itself would be your hardware device, the TOTP secret would be stored in the TPM and theoretically impossible to steal/copy. Of course this means you will probably want a mobile device (possibly a second laptop also) as a backup.)

>But okay, you may extend my attack by saying that you exchange the motherboard between the victim and the attacker laptop, so that you don't need to replicate the chassis.

Modern computers has tamper detection and if you open them you'll need to type the BIOS password.

However, replacing the motherboard is going to replace the TPM. This is easily detectable with something like tpm2_totp in the bootchain.

https://github.com/tpm2-software/tpm2-totp

You could also use TOTP for a kind of remote attestation (e.g., with your phone computing TOTP). In this setup, the CPU sends the timestamp to the TPM, and it returns the TOTP value. So instead of you looking at your phone to give the TOTP to a service provider to prove that you're in possession of your phone, the computer gives you a TOTP value to prove that it's in possession (inside the TPM, sealed to the boot chain hashes) of the TOTP secret, and you use your phone to verify this. A possible weakness (short of a full-blown TPM compromise) would be to send a bunch of forged timestamps to the TPM while your computer is running and store the resulting TOTP values, then tamper with Secure Boot and emit the precomputed TOTP corresponding to the current timestamp whenever you boot up your computer. But this would require running malicious code on your compute while you're logged in with the trusted boot chain.