hmac_sha1_usingrawkey(9)

💅 hmac_sha1_usingrawkey — the kernel API manual, bestie edition ✨

okay so this is hmac_sha1_usingrawkey from the Kernel API Manual, and she is literally the one-shot queen 👑 — you hand her a raw key, a message, and she hands you back an HMAC-SHA1 and dips. no cap.

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🌸 NAME 🌸

hmac_sha1_usingrawkey — compute HMAC-SHA1 in one shot, using a raw key 🎀

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✨ SYNOPSIS ✨

void hmac_sha1_usingrawkey (const u8 *raw_key , size_t raw_key_len ,
       const u8 *data , size_t data_len , u8 out[static SHA1_DIGEST_SIZE] );

like. that's the whole vibe. five args, one call, done 🫶

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🦋 ARGUMENTS 🦋

• raw_key — the raw HMAC-SHA1 key, bestie. that's the secret sauce 💜
• raw_key_len — the key length in bytes. and listen — all key lengths are supported ✨ no gatekeeping, we love to see it.
• data — the message data 🍓
• data_len — the data length in bytes, fr fr
• out — (output) the resulting HMAC-SHA1 value 💖 this is where the magic lands, main character energy only

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🌈 DESCRIPTION 🌈

so here's the tea ☕ — if you're using the key multiple times, pleaseeee prefer hmac_sha1_preparekey followed by multiple calls to hmac_sha1 instead. it's giving efficiency, it's giving respect for your CPU's time 💅

like don't be out here re-doing the key work every single call, that's not the move 😭

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🧚 CONTEXT 🧚

Any context. literally any. she doesn't care where you are, she'll slay anyway ⭐

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🔥 SEE ALSO 🔥

Kernel file ./include/crypto/sha1.h — plus the whole friend group, all of them, in order:

• struct sha1_ctx(9)
• sha1_init(9)
• sha1_update(9)
• sha1_final(9)
• sha1(9)
• struct hmac_sha1_key(9)
• struct hmac_sha1_ctx(9)
• hmac_sha1_preparekey(9)
• hmac_sha1_init(9)
• hmac_sha1_init_usingrawkey(9)
• hmac_sha1_update(9)
• hmac_sha1_final(9)
• hmac_sha1(9)

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🎀 and that's the wrap 🎀

this iconic little page lives over in ./include/crypto, version dated October 2026 — bestie, she's from the future and she still ate 💀💖 bye, go hash something responsibly! 🦋