aes_ccm_auth_update(9)

💖 NAME 💖

Okay so bestie, this is aes_ccm_auth_update(9) from the Kernel API Manual, and it is literally the function for incrementally processing AES-CCM associated data. Slay. ✨

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✨ SYNOPSIS ✨

void aes_ccm_auth_update (struct aes_ccm_ctx *ctx , const u8 *ad ,
       size_t len );

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🎀 ARGUMENTS 🎀

• ctx — an AES-CCM context. Your main-character struct. 💅
• ad — the associated data. Yes, the actual associated-data bits. 🎀
• len — length of the associated data in bytes. A number, bestie. 🌸

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💅 DESCRIPTION 💅

Okay, listen up, because this is the part where you do not get to vibe-check your way past the rules:

IMPORTANT: Callers MUST NOT assume that any decrypted or associated data is authentic until the authentication tag has been verified.

Periodt. Do not trust the data until the tag says yes. 💀

Also: the total length of the associated data (over all calls to this function) MUST match the ad_len that was passed to aes_ccm_init. Not “roughly match.” Not “match if you feel like it.” MUST. Match. 🫶

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🌈 CONTEXT 🌈

Any context. That’s it. That’s the context rule. Literally any. 👑

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🦋 SEE ALSO 🦋

Kernel file ./include/crypto/aes-ccm.h — yes, that exact path, bestie — plus the whole friend group:

• struct aes_ccm_key(9)
• struct aes_ccm_ctx(9)
• aes_ccm_preparekey(9)
• aes_ccm_encrypt(9)
• aes_ccm_decrypt(9)
• aes_ccm_init(9)
• aes_ccm_encrypt_update(9)
• aes_ccm_decrypt_update(9)
• aes_ccm_encrypt_final(9)
• aes_ccm_decrypt_final(9)

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Okay that’s the whole page, bestie. This one lives under ./include/crypto and the date/version vibe is October 2026. Now go verify that authentication tag before you trust literally anything. Mwah 💋🫶