Actually it's possible with a middleman authority.
In Italy there is the "pec" email system that works exactly like this.
dtonon / daniele
npub1000…vwqk
2024-05-30 17:30:36
in reply to nevent1q…lrlw
Author Public Key
npub10000003zmk89narqpczy4ff6rnuht2wu05na7kpnh3mak7z2tqzsv8vwqkPublished at
2024-05-30 17:30:36Event JSON
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"created_at": 1717083036,
"kind": 1,
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"content": "Actually it's possible with a middleman authority.\nIn Italy there is the \"pec\" email system that works exactly like this.",
"sig": "ed884fbeb106c97f72a27d01ccf02f58abac93963a6bb0c77b7fcb8027c034c2d824ea9c60df51821d9e35dc9eb0c14d82cb93201d0337a2c37e236322bcc5b1"
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