crypto_akcipher_maxsize(9)

💅 crypto_akcipher_maxsize(9) 💅

okay bestie, welcome to the Kernel API Manual ✨ this is crypto_akcipher_maxsize(9) and it's honestly a tiny little legend — it tells you how big your output buffer needs to be. that's it. that's the whole vibe. 🎀

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✨ NAME ✨

crypto_akcipher_maxsize — get the len for your output buffer 🫶

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🌸 SYNOPSIS 🌸

unsigned int crypto_akcipher_maxsize (struct crypto_akcipher *tfm );

like, that's the whole signature. short king energy 👑

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🦋 ARGUMENTS 🦋

• tfm — your AKCIPHER tfm handle, and it's gotta be one you allocated with crypto_alloc_akcipher. no borrowing from your mutuals, allocate your own 💖

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🎀 DESCRIPTION 🎀

so the function returns the dest buffer size required for a given key ✨ that's the whole point. it's a size-checker, a little "hey how much room do i need" moment.

now the part you cannot skip, bestie, because it's giving ⚠️:

Function assumes that the key is already set in the transformation.

and like — if you call this without a setkey, or after a setkey that failed? you will end up in a NULL dereference. 💀 not cute. not the move. that's a crash, fr fr. so set your key first, check you didn't fail, and then come ask for the maxsize. periodt.

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💜 SEE ALSO 💜

• Kernel file ./include/crypto/akcipher.h 📁
• struct akcipher_request(9)
• struct crypto_akcipher(9)
• struct akcipher_alg(9)
• Generic Public Key Cipher API(9)
• crypto_alloc_akcipher(9)
• crypto_free_akcipher(9)
• akcipher_request_alloc(9)
• akcipher_request_free(9)
• akcipher_request_set_callback(9)
• akcipher_request_set_crypt(9)
• crypto_akcipher_encrypt(9)
• crypto_akcipher_decrypt(9)
• crypto_akcipher_sync_encrypt(9)
• crypto_akcipher_sync_decrypt(9)
• crypto_akcipher_set_pub_key(9)
• crypto_akcipher_set_priv_key(9)

like literally the whole akcipher friend group, go say hi 🌈

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and that's the whole page babes — brought to you by the fine people at ./include/crypto 🌸, dropping October 2026 (yes, future girlie 💅), and this was crypto_akcipher_maxsize(9) 🧚 stay safe, set your keys, and don't NULL-deref on main 💖✨🫶