HPKE has the benefit of being standardized, and imperfect forward secrecy is the best you can do with 0-RTT (which probably fits the fediverse model better).
Just be very careful about the "use correctly" and it's "fine". I'm partial to Noise (https://noiseprotocol.org/) for these sort of use cases because it has less foot+guns and there's more flexibility, but I wouldn't freak out or scream if I saw HPKE in use.
As a side note, it is indeed safe to convert ed25519 keys to X25519 keys assuming a common sense step is taken when using the latter (https://eprint.iacr.org/2021/509).
Grey Area
npub1hn…egxx0
2026-07-17 17:15:56 UTC
in reply to nevent1q…tzvz
Author Public Key
npub1hnhlnl0md39xrq7nr6gh80zjk2zatw5flaxmdrx2wwa7hf2qcgusxegxx0Seen on
wss://relay.momostr.pinkPublished at
2026-07-17 17:15:56 UTCEvent JSON
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"content": "HPKE has the benefit of being standardized, and imperfect forward secrecy is the best you can do with 0-RTT (which probably fits the fediverse model better).\n\nJust be very careful about the \"use correctly\" and it's \"fine\". I'm partial to Noise (https://noiseprotocol.org/) for these sort of use cases because it has less foot+guns and there's more flexibility, but I wouldn't freak out or scream if I saw HPKE in use.\n\nAs a side note, it is indeed safe to convert ed25519 keys to X25519 keys assuming a common sense step is taken when using the latter (https://eprint.iacr.org/2021/509).",
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