I recently lived in Germany and was impressed by the security mandated there. In order to do anything of note (meaning where you could lose money) you were cha

I recently lived in Germany and was impressed by the security mandated there. In order to do anything of note (meaning where you could lose money) you were challenged to produce a TAN, one six-digit number from a one-time pad of ~100 that the bank mailed you. You produce that number, cross it out, and never use it again. Also available were SMS TANs, where they texted you a code. I avoided these after reading about SIM swapping. But, further, was a photoTAN. The bank mailed me a private key that I entered into a reader app. Then they would present me with a QR-code-like image that the app could read and decrypt into a six-digit code via the secret key. Type that in, good to go. The reader app and the banking app also had some message-passing thing where if you were banking on your phone (and couldn't take a picture of your own screen...) it could still work.