crypto_shash_export(9)

🎀 NAME 🎀

okay bestie 💖 this is crypto_shash_export(9) from the Kernel API Manual, and it’s literally here to extract operational state for message digest. slay.

✨ SYNOPSIS ✨

int crypto_shash_export (struct shash_desc *desc , void *out );

🌸 ARGUMENTS 🌸

• desc — reference to the operational state handle whose state is exported. like, the handle you’re grabbing the state from 🫶
• out — output buffer of sufficient size that can hold the hash state. no tiny-buffer energy, okay? 😭

💖 DESCRIPTION 💖

So this function exports the hash state of the operational state handle into the caller-allocated output buffer out, which must have sufficient size — e.g. by calling crypto_shash_descsize. That’s the whole vibe: grab the state, put it in out, make sure out is big enough 💅

bestie, the size part is not a suggestion. out must have sufficient size, and crypto_shash_descsize is the example the page gives for getting it. periodt. 💀

🦋 CONTEXT 🦋

Call it in Softirq or process context. that’s it, that’s the context. ✨

⭐ RETURN ⭐

• 0 if the export creation was successful 🎉
• < 0 if an error occurred 😭

🌈 SEE ALSO 🌈

The whole squad, bestie — every single one is invited 🫶:

• Kernel file ./include/crypto/hash.h and Message Digest Algorithm Definitions(9) 📁
• struct ahash_alg(9), struct shash_alg(9), Asynchronous Message Digest API(9)
• async digest crew: crypto_alloc_ahash(9), crypto_free_ahash(9), crypto_has_ahash(9), crypto_ahash_blocksize(9), crypto_ahash_digestsize(9), crypto_ahash_statesize(9), crypto_ahash_reqtfm(9), crypto_ahash_reqsize(9), crypto_ahash_setkey(9), crypto_ahash_finup(9), crypto_ahash_final(9), crypto_ahash_digest(9), crypto_ahash_export(9), crypto_ahash_import(9), crypto_ahash_init(9), crypto_ahash_update(9) ✨
• async request besties: Asynchronous Hash Request Handle(9), ahash_request_set_tfm(9), ahash_request_alloc(9), ahash_request_free(9), ahash_request_set_callback(9), ahash_request_set_crypt(9), ahash_request_set_virt(9) 🦋
• sync digest crew: Synchronous Message Digest API(9), crypto_alloc_shash(9), crypto_free_shash(9), crypto_shash_blocksize(9), crypto_shash_digestsize(9), crypto_shash_descsize(9), crypto_shash_setkey(9), crypto_shash_digest(9), crypto_shash_tfm_digest(9), crypto_shash_import(9), crypto_shash_init(9), crypto_shash_finup(9), crypto_shash_update(9), crypto_shash_final(9) 🌟

That’s the whole page, bestie 🫶 source file ./include/crypto, dated October 2026, and the page is crypto_shash_export(9) — byeee 💅✨