sha256_update(9)

👑 sha256_update — like, the Kernel API Manual, section 9, bestie ✨

okay so you're in the kernel, you've got a SHA-256 thing going on, and you need to feed it more message data. that's literally this function. welcome 🫶

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🌸 NAME 🌸

sha256_update — update a SHA-256 context with message data. that's it, that's the whole job, and it ate 💅

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✨ SYNOPSIS ✨

void sha256_update (struct sha256_ctx *ctx , const u8 *data , size_t len
);

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🎀 ARGUMENTS 🎀

• ctx — the context you're updating. no cap, it must have been initialized first — don't come at this function with a raw uninitialized context, that's not the vibe 😭
• data — the message data itself. the actual bytes. the main character 🦋
• len — how long data is, in bytes. size matters and we respect it 💜

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💖 DESCRIPTION 💖

This can be called any number of times. literally as many as you want. zero, one, forty-seven, go off 👑

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🌈 CONTEXT 🌈

Any context. all of them. every single one. no restrictions, we're flexible like that 💅✨

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🧚 SEE ALSO 🧚

so there's a whole friend group here and honestly the way this page lists every single one of them? iconic. here's the roster, no one gets left out 🫶

Kernel file ./include/crypto/sha2.h, plus:

• 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_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), hmac_sha384_usingrawkey(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)

iykyk 💫

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and that's the whole page, bestie — brought to you by ./include/crypto, dated October 2026, filed under sha256_update(9). stan a stable ABI, mwah 💋🎀