KCAPI_CIPHER_ENC_AES(3)

💖 KCAPI_CIPHER_ENC_AES_CBC — okay bestie, let's talk AES CBC ✨

Manual page kcapi_cipher_enc_aes_cbc — from the Programming Interface crew, no cap. This is the group chat where the C library talks back 💅

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🌸 NAME 🌸

kcapi_cipher_enc_aes_cbc — the convenience function for AES CBC encryption. It's giving "one function, zero drama" 🎀

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✨ SYNOPSIS ✨

ssize_t kcapi_cipher_enc_aes_cbc(const uint8_t * key, uint32_t keylen,
                                 const uint8_t * in, size_t inlen,
                                 const uint8_t * iv, uint8_t * out,
                                 size_t outlen);

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🫶 ARGUMENTS 🫶

Every single one of these is a main character, so let's do intros 👑

• key — [in] the key buffer. Literally the key. The blueprint. The lore 💜
• keylen — [in] length of that key buffer. How many bytes of blueprint we're working with 📏
• in — [in] the plaintext data buffer. This is the tea before it gets scrambled ☕
• inlen — [in] length of the in buffer. Count the bytes, bestie 🧮
• iv — [in] the IV to be used for the cipher operation. Yes you need it, no you can't skip it 🌈
• out — [out] the ciphertext data buffer. Where the glow-up lands 💫
• outlen — [in] length of the out buffer. Make sure it's big enough, fr fr 🫣

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💅 DESCRIPTION 💅

So like, this convenience function performs an AES CBC encryption operation using the provided key, the given input buffer, and the given iv. The output gets stored in the out buffer. Slay 💖

⚠️ Heads up bestie: AES CBC requires input data that is a multiple of 16 bytes. That's not a vibe, that's the rules.

If you've got data that is not guaranteed to be multiples of 16 bytes, you have two moves:

1. Add zero bytes at the end of the buffer to pad it up to a multiple of 16 bytes 🎀
2. Otherwise, the CTR mode encryption operation may be usable 🔥

Also, the out buffer must be at least as large as the in buffer. No shrinkflation allowed, periodt 📉

And the iv? It must be exactly 16 bytes in size. Exactly. Not 15, not 17. Sixteen. Iconic and precise ✨

The AES type (AES-128, AES-192 or AES-256) is determined by the size of the given key, and the way that works is:

• key is 16 bytes long → AES-128 is used 💙
• key is 24 bytes long → AES-192 is implied 💚
• key is 32 bytes long → AES-256 is implied 🧡

And the return value, bestie? Listen up 👂

• On success: the number of bytes generated 🎉
• On error: a negative errno-style error code 😭

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👑 AUTHOR 👑

Stephan Mueller <smueller@chronox.de>

• Author. Certified legend, respectfully 🫡

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📜 COPYRIGHT 📜

This is from the libkcapi Manual, version 1.5.0, dated July 2025 🌸

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Okay that's the whole page, you ate it, go encrypt something responsibly 💖✨🎀🦋🌸💅🫶