blog! “Can time-travellers use TOTP codes?”
Imagine, just for a moment, you and your friends decide to travel in time. In order to make sure you can authenticate your communications with each other, you set up a shared Time-based One Time Password (TOTP). The TOTP algorithm uses a Hash-based Message Authentication Code (HMAC). The hash is calculated from a shared …
Read more: https://shkspr.mobi/blog/2024/07/can-time-travellers-use-totp-codes/
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#ComputerScience #standards #totp
@Edent fun question of how your totp device knows the time. If you've gone back before the 70s there isn't GPS to sync to. If the totp device doesn't know it's time travelling then it's clock probably still thinks its minutes after it left. Hope all of you jumped at the same time.
If you jump back to the same time you left, you now get clock drift errors as you've accumulated the time you spent in the past and your clock thinks it's in the future.
Of course if you've invented a time machine you can probably make a clock that understands that it's been time travelled.