crypto_aead_decrypt(9)

📦 version 7.3.1, in nixpkgs unstable

💅 crypto_aead_decrypt — Kernel API Manual

okay bestie, buckle up, we're doing kernel crypto today ✨ this is crypto_aead_decrypt(9), straight out of the Kernel API Manual, and honestly? she's iconic.

🌸 NAME 🌸

crypto_aead_decrypt — decrypt ciphertext. that's it. that's the whole job. she decrypts. 💖

🎀 SYNOPSIS 🎀

int crypto_aead_decrypt (struct aead_request *req );

🦋 ARGUMENTS 🦋

  • req — a reference to the aead_request handle that's holding all the info needed to actually run the cipher operation. think of it as the little purse 👜 carrying everything the crypto op needs. no purse, no decrypt, periodt.

✨ DESCRIPTION ✨

so what does she do? she decrypts ciphertext data using that aead_request handle. the whole deal with that data structure — like, how it gets filled up with data in the first place — is discussed over with the aead_request_* functions. go read those if you're lost, iykyk. 🫶

⚠️ IMPORTANT NOTE ⚠️ the caller must concatenate the ciphertext followed by the authentication data / tag. and that authentication data / tag has to have the size defined by the crypto_aead_setauthsize invocation. no cap, if you get this order or size wrong, the auth check is gonna fail and you're gonna have a bad time. 😭

🔥 RETURN 🔥

  • 0 — cipher operation was successful, slay, we ate. 👑
  • -EBADMSG — so here's the thing: an AEAD cipher operation performs authentication of the data during the decryption operation. that means this error comes back when the authentication of the ciphertext was unsuccessful — i.e. the integrity of the ciphertext or the associated data was violated. 💀 somebody tampered with something, or something got messed up.
  • < 0 — if an error occurred. any other negative value, basically. it's giving "something went wrong, check your vibes." 🙈

🌈 SEE ALSO 🌈

go read the kernel file ./include/crypto/aead.h and the Authenticated Encryption With Associated Data (AEAD) Cipher API(9), plus all these besties:

and that's the whole page, bestie 🧚✨ this one came from ./include/crypto, dated October 2026, in the Kernel API Manual — literally stamped and everything. go forth and decrypt responsibly 💜🍓

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