nvme_auth_a...ed_challenge(9)

🌸 NAME 🌸

nvme_auth_augmented_challenge — compute the augmented DH-HMAC-CHAP challenge. Okay so this page is from the Kernel API Manual, page id nvme_auth_a...ed_challenge(9), and we're about to make the augmented challenge make sense, bestie 💖

✨ SYNOPSIS ✨

int nvme_auth_augmented_challenge (u8 hmac_id , const u8 *skey , size_t
       skey_len , const u8 *challenge , u8 *aug , size_t hlen );

🎀 ARGUMENTS 🎀

• hmac_id — hash algorithm identifier, periodt. This is the ID that says which hash algorithm we're working with.
• skey — session key. Main character energy, honestly.
• skey_len — length of skey.
• challenge — challenge value. The challenge in question 💅
• aug — output buffer for the augmented challenge. This is where the glow-up goes.
• hlen — hash output length (length of challenge and aug).

🦋 DESCRIPTION 🦋

NVMe base specification 8.3.5.5.4: the augmented challenge is computed applying the HMAC function using the hash function H selected by the HashID parameter ... with the hash of the ephemeral DH key ... as HMAC key to the challenge C (i.e., Ca = HMAC(H(g^xy mod p), C)). Literally the math is the moment 🔥

As the session key skey is already H(g^xy mod p) per section 8.3.5.5.9, use it directly as the HMAC key without additional hashing. Slay — no extra hashing arc needed 💖

💅 RETURN 💅

0 on success, negative errno on failure. That's the whole vibe check: zero means we ate, negative errno means something went wrong 😭

🌈 SEE ALSO 🌈

• Kernel file: ./drivers/nvme/common/auth.c
• nvme_auth_gen_session_key(9)
• nvme_auth_generate_psk(9)
• nvme_auth_generate_digest(9)
• nvme_auth_derive_tls_psk(9)

Go read these next, bestie — they're all in the same friend group 🫶

okay bye bestie 🫶 this page lives at ./drivers/nvme/common, dated October 2026, and it's nvme_auth_a...ed_challenge(9) in the Kernel API Manual — mwah 💋