The blinded signatures protect you from this issue:
* Alice gets a coin from the mint and gives it to Bob
* Bob redeems it
* The mint now knows that the coin Bob redeemed is the same one that was given to Alice.
With blinded signatures, the mint only knows that the coin was minted and given to someone, but not to whom. Coins are fixed sizes, so your anonymity set is the number of people who have coins of the same size.
Of course there are probably tons of heuristics you could use to guess who sent coins to whom, which get harder the more users are using the mint.
rfkill
npub1c5…60cv9
2024-07-29 14:42:46
in reply to nevent1q…vjk5
Author Public Key
npub1c5nnqaw7q23tamddg58lvrcdglr8729z9x0msprpr5lw2gva7h6qr60cv9Published at
2024-07-29 14:42:46Event JSON
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"pubkey": "c5273075de02a2beedad450ff60f0d47c67f28a2299fb804611d3ee5219df5f4",
"created_at": 1722256966,
"kind": 1,
"tags": [
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"content": "The blinded signatures protect you from this issue:\n\n* Alice gets a coin from the mint and gives it to Bob\n* Bob redeems it\n* The mint now knows that the coin Bob redeemed is the same one that was given to Alice.\n\nWith blinded signatures, the mint only knows that the coin was minted and given to someone, but not to whom. Coins are fixed sizes, so your anonymity set is the number of people who have coins of the same size.\n\nOf course there are probably tons of heuristics you could use to guess who sent coins to whom, which get harder the more users are using the mint.",
"sig": "0baad672cdc5632d89a3bb2fd1f4a6c636a6f928f4d1ea734fafc4e680c89440ecd3e4d2ea88482c19ed50cf2fcbcc0ac26c7e8734e19a11b72869e3b8072178"
}