aes_xcbcmac_preparekey(9)

💅 aes_xcbcmac_preparekey(9) — like, the Kernel API Manual entry, bestie

okay so real talk: this is a section 9 manpage from the Kernel API Manual, and it's about prepping a key for AES-XCBC-MAC. it's short, it's sweet, it's giving "small function, big responsibilities" energy ✨ let's get into it 🫶

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🌸 NAME 🌸

aes_xcbcmac_preparekey — literally just Prepare a key for AES-XCBC-MAC 💖 that's the whole assignment, no cap.

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✨ SYNOPSIS ✨

void aes_xcbcmac_preparekey(struct aes_cmac_key *key,
                            const u8 in_key[static AES_KEYSIZE_128]);

so it returns void (nothing back, she's a doer not a returner 💅), takes a struct aes_cmac_key * and a const u8 array that's static AES_KEYSIZE_128 long. that's it. that's the vibe 🌈

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🎀 ARGUMENTS 🎀

• key — (output) the key struct you're gonna initialize. this is the one getting the glow-up ✨ she comes in empty, she leaves prepared 🧚
• in_key — the raw key, bestie. and per the AES-XCBC-MAC specification (RFC 3566), this bad boy is 128 bits, which matches the internal use of AES-128 👑 like, exactly 128 bits, don't try to be cute and pass something else fr fr

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💜 DESCRIPTION 💜

okay so here's the tea ☕: AES-XCBC-MAC and AES-CMAC are lowkey the same thing except for the key preparation step. that's the only difference. everything else? identical energy 💀

after that key-prep step happens, AES-XCBC-MAC is fully supported via the aes_cmac_* functions — the way that she just slots right into the CMAC family like she was always there 🫶

🚨 and like, a gentle heads-up from the docs themselves: New users should use AES-CMAC instead of AES-XCBC-MAC. so if you're new here, pick CMAC. it's the main character now 👑

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🦋 CONTEXT 🦋

Any context. literally any. she does not care where you call her from, she's flexible like that 💅✨

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🔥 SEE ALSO 🔥

• the Kernel file ./include/crypto/aes-cbc-macs.h 📁
• struct aes_cmac_key(9)
• aes_cmac_zeroize_key(9)
• struct aes_cmac_ctx(9)
• aes_cmac_zeroize_ctx(9)
• aes_cmac_preparekey(9)
• aes_cmac_init(9)
• aes_cmac_update(9)
• aes_cmac_final(9)
• aes_cmac(9)

go read those too, iykyk 📚💖

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⭐ sign-off ⭐

and that's the page!! screams from the ./include/crypto source, dated October 2026 🗓️✨ go prep those keys responsibly bestie, mwah 💋🎀🦋