KCAPI_MD_DIGEST(3)

💖 kcapi_md_digest — calculate message digest on buffer (one-shot)

okay bestie, welcome to the libkcapi manual, page kcapi_md_digest(3) 💅 this one's the one-shot digest glow-up — no streaming, no drip-feeding bytes, just one call and boom, hash. let's get into it 🫶

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✨ SYNOPSIS ✨

ssize_t kcapi_md_digest(struct kcapi_handle * handle,
                        const uint8_t * in, size_t inlen, uint8_t * out,
                        size_t outlen);

that's the whole vibe, fr fr 🌸

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🎀 ARGUMENTS 🎀

• handle — [in] the cipher handle, your main character 🔑
• in — [in] buffer with the input data, aka the stuff you want hashed
• inlen — [in] length of the input buffer, tell her how much she's working with
• out — [out] buffer for the message digest — yes it's an out, she gets written into 💖
• outlen — [in] length of out

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🌈 DESCRIPTION 🌈

so with this one-shot function, a message digest of the given buffer gets generated. literally one call, one digest, no notes 👑

the output buffer must be allocated by the caller — that's on you, bestie, not on the library 🙈 — and it has to have at least the length of the message digest size for whichever message digest you chose. undersized buffer? we'll get to that, and it's giving ✨truncated✨.

the message digest handle must have been initialized, potentially by also setting the key using the generic message digest API functions. no init, no digest, that's the rule 💅

also the input buffer can be at most INT_MAX in size. that's the ceiling, periodt.

and here's the return tea ☕:

• return size of message digest upon success 🎉
• -EIO — data cannot be obtained 😭
• -ENOMEM — buffer is too small for the complete message digest, and the buffer is filled with the truncated message digest 💀

bestie warning fr fr: that -ENOMEM case isn't just an error, it's also an action. your out buffer gets stuffed with a truncated message digest. so you get a partial digest AND an error code. iconic behaviour, honestly. check your sizes before you call this, i am begging 🫶

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👑 AUTHOR 👑

• Stephan Mueller <smueller@chronox.de>
  • Author.

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💜 COPYRIGHT 💜

that's the page, bestie!! this was the libkcapi Manual, version 1.5.0, dated July 2025 — kcapi_md_digest(3), no cap. go hash something and slay 💅✨🦋🌸🎀