From their side
A black card with no story.
There is no name, no logo of a bank, no serial number that means anything, no hint of what it belongs to. It reads as a hotel key or a membership card, which is the point.
If they are curious and technical, they can read the data stored on it. What they get is a block of encrypted bytes, not entries, not labels, not a list of what you own.
To turn that into your secrets they would need your password, and there is no attempt counter to grind, no hint, no reset link, and nobody at MI8OS who can help them. There is also nothing on the card that tells them who you are, so nothing to target.
What to do
If you lose one of three.
-
I
Stay calm, then act
A lost card is not an open vault. It is an encrypted object in the hands of someone who probably throws it away.
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II
Change the password
Choose a new one on your phone and rewrite the cards you still hold. The lost card keeps the old password, so retire what it protects.
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III
Rotate what matters
For anything critical, change the underlying secret itself: the master password, the account, the code. Then write the fresh vault.
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IV
Replace the copy
Back to three cards, three places. The set is meant to be rewritten.
A card should be
boring to find.Blank on purpose: no branding to advertise value, no identity to link it to you, nothing readable without the password you never wrote down beside it.