hmac_sha384_usingrawkey(9)

💅 hmac_sha384_usingrawkey(9) — Kernel API Manual, bestie edition

okay so first things first, this is a page from the Kernel API Manual, and the star of the show is hmac_sha384_usingrawkey(9). She does exactly one thing and she does it flawlessly. Let's get into it 🎀

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✨ NAME ✨

hmac_sha384_usingrawkey — compute HMAC-SHA384 in one shot, using a raw key. one shot!! no preamble, no warm-up, we're just doing it 💅

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🦋 SYNOPSIS 🦋

void hmac_sha384_usingrawkey (const u8 *raw_key , size_t raw_key_len ,
       const u8 *data , size_t data_len , u8 out[static SHA384_DIGEST_SIZE] );

like, look at that signature. five params, zero drama. the out buffer is literally sized for you at SHA384_DIGEST_SIZE, the compiler has your back fr fr 🫶

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🌸 ARGUMENTS 🌸

• raw_key — the raw HMAC-SHA384 key. raw as in unprepared, bestie, straight off the street 🧚
• raw_key_len — the key length in bytes. and listen: all key lengths are supported. every single one. no judgment, no minimum, no "sorry that's too short" energy. iconic 👑
• data — the message data. the actual tea being hashed ☕
• data_len — the data length in bytes.
• out — (output) the resulting HMAC-SHA384 value. she's the main character of this function, no cap 💖

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💜 DESCRIPTION 💜

so here's the vibe check: this is the one-shot version. you hand her a raw key, she computes the HMAC-SHA384, done, bye ✨

but listen closely, bestie, because this is the important part 👇

If you're using the key multiple times, prefer to use hmac_sha384_preparekey followed by multiple calls to hmac_sha384 instead.

like yeah this one works, but if that key is gonna be reused, do the prepare-once-then-call-many thing. it's giving efficiency, it's giving respect for your CPU, it's giving "I read the whole manpage" 😌🔥

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🌈 CONTEXT 🌈

Any context. literally any. she's flexible like that. no asterisks, no caveats, go off wherever you are 🦋

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⭐ SEE ALSO ⭐

okay this list is long and she ate, every single one of these is here:

• Kernel file ./include/crypto/sha2.h
• struct sha224_ctx(9)
• sha224_init(9)
• sha224_update(9)
• sha224_final(9)
• sha224(9)
• struct hmac_sha224_key(9)
• struct hmac_sha224_ctx(9)
• hmac_sha224_preparekey(9)
• hmac_sha224_init(9)
• hmac_sha224_init_usingrawkey(9)
• hmac_sha224_update(9)
• hmac_sha224_final(9)
• hmac_sha224(9)
• hmac_sha224_usingrawkey(9)
• struct sha256_ctx(9)
• sha256_init(9)
• sha256_update(9)
• sha256_final(9)
• sha256(9)
• sha256_finup_2x(9)
• sha256_finup_2x_is_optimized(9)
• struct hmac_sha256_key(9)
• struct hmac_sha256_ctx(9)
• hmac_sha256_preparekey(9)
• hmac_sha256_init(9)
• hmac_sha256_init_usingrawkey(9)
• hmac_sha256_update(9)
• hmac_sha256_final(9)
• hmac_sha256(9)
• hmac_sha256_usingrawkey(9)
• struct sha384_ctx(9)
• sha384_init(9)
• sha384_update(9)
• sha384_final(9)
• sha384(9)
• struct hmac_sha384_key(9)
• struct hmac_sha384_ctx(9)
• hmac_sha384_preparekey(9)
• hmac_sha384_init(9)
• hmac_sha384_init_usingrawkey(9)
• hmac_sha384_update(9)
• hmac_sha384_final(9)
• hmac_sha384(9)
• struct sha512_ctx(9)
• sha512_init(9)
• sha512_update(9)
• sha512_final(9)
• sha512(9)
• struct hmac_sha512_key(9)
• struct hmac_sha512_ctx(9)
• hmac_sha512_preparekey(9)
• hmac_sha512_init(9)
• hmac_sha512_init_usingrawkey(9)
• hmac_sha512_update(9)
• hmac_sha512_final(9)
• hmac_sha512(9)
• hmac_sha512_usingrawkey(9)

that's the whole family reunion right there, all 57 of them, and yes I counted 😭💀

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and that's the page!! this lil gem lives over in ./include/crypto, shipped with the October 2026 version of the kernel docs. go hash something, bestie, you're gonna slay it 💖✨🎀🫶