KCAPI_CIPHER_ENCRYPT(3)

📦
version 1.5.0 · 7 versions
, in fedora 43

💖 KCAPI_CIPHER_ENCRYPT(3) 💖

okay bestie, welcome to the Programming Interface section of the libkcapi manual — this one's all about kcapi_cipher_encrypt_aio, the async one-shot encryption girlie. she's giving "send your plaintext, get your ciphertext, no drama" and honestly? iconic. let's get into it 🫶

✨ NAME ✨

kcapi_cipher_encrypt_aio — encrypt data (asynchronous one shot) 🔥

🌸 SYNOPSIS 🌸

ssize_t kcapi_cipher_encrypt_aio(struct kcapi_handle * handle,
                                 struct iovec * iniov,
                                 struct iovec * outiov, size_t iovlen,
                                 const uint8_t * iv, int access);

🎀 ARGUMENTS 🎀

  • handle — [in] your cipher handle, the main character of this whole operation 💅
  • iniov — [in] head of the scatter-gather list array holding the plaintext (the stuff you wanna hide 👀)
  • outiov — [out] head of the scatter-gather list of the destination buffers, which get filled with the ciphertext ✨
  • iovlen — [in] number of scatter-gather list entries, bestie. count them.
  • iv — [in] the IV to be used for the cipher operation 🌈
  • access — [in] kernel access type, and you have three flavors to choose from:
    • KCAPI_ACCESS_HEURISTIC — use the internal heuristic for the fastest kernel access 🏃‍♀️💨
    • KCAPI_ACCESS_VMSPLICE — use vmsplice access
    • KCAPI_ACCESS_SENDMSG — sendmsg access

🦋 DESCRIPTION 🦋

So here's the vibe: each individual scatter-gather list entry gets processed with separate invocations of the given cipher. not one big call — separate ones. noted. 💀

Your memory should be aligned at the page boundary using posix_memalign(sysconf(_SC_PAGESIZE)). and like, if it's not aligned at the page boundary, the vmsplice call may not send all data to the kernel — so yeah, that's a real one, don't skip it. 🙈

Also: the IV buffer must be exactly kcapi_cipher_ivsize bytes in size. not more, not less. periodt.

And what do you get back? the number of bytes encrypted upon success 🎉 — or a negative errno-style error code if an error occurred 😭

👑 AUTHOR 👑

Stephan Mueller <smueller@chronox.de> — Author.

this one's short and sweet, no cap.

okay that's the whole page, bestie, you ate that 🍓🧚

libkcapi Manual 1.5.0, July 2025 — mwah, take care of her 💖✨

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