RIJNDAEL(9)

💖 NAME 💖

okay so bestie, this is RIJNDAEL(9) from the Kernel Developer's Manual, and it is literally the page for AES encryption ✨. The whole squad is:

• rijndael_makeKey
• rijndael_cipherInit
• rijndael_blockEncrypt
• rijndael_padEncrypt
• rijndael_blockDecrypt
• rijndael_padDecrypt

🌸 SYNOPSIS 🌸

Here's the exact include-and-signature moment, no cap:

#include <sys/types.h>
#include <crypto/rijndael.h>

int
rijndael_makeKey(keyInstance *key, uint8_t direction, int keyLen,
    char *keyMaterial);

int
rijndael_cipherInit(cipherInstance *cipher, uint8_t mode, char *IV);

int
rijndael_blockEncrypt(cipherInstance *cipher, keyInstance *key,
    uint8_t *input, int inputLen, uint8_t *outBuffer);

int
rijndael_padEncrypt(cipherInstance *cipher, keyInstance *key,
    uint8_t *input, int inputOctets, uint8_t *outBuffer);

int
rijndael_blockDecrypt(cipherInstance *cipher, keyInstance *key,
    uint8_t *input, int inputLen, uint8_t *outBuffer);

int
rijndael_padDecrypt(cipherInstance *cipher, keyInstance *key,
    uint8_t *input, int inputOctets, uint8_t *outBuffer);

🎀 DESCRIPTION 🎀

So rijndael_makeKey() is the function that sets up the key schedule in key. It’s giving “get your key situation ready” energy 💅.

The direction tells it what the key is for, and it may be DIR_ENCRYPT or DIR_DECRYPT.

The key length in bits lives in keyLen, and it must be 128, 192 or 256. No random numbers, bestie 😭.

The actual key comes from the buffer pointed to by keyMaterial. That material may be raw binary data, or an ASCII string containing a hexadecimal rendition of the raw binary data. Which one? It depends on a compile-time option in the rijndael_makeKey sources: BINARY_KEY_MATERIAL.

🦋 RETURN VALUES 🦋

rijndael_makeKey() returns:

• BAD_KEY_INSTANCE if a NULL key is passed.
• BAD_KEY_DIR if direction is not DIR_ENCRYPT or DIR_DECRYPT.
• BAD_KEY_MAT if the key materials are not a hexadecimal string (and binary keys are not set).
• TRUE otherwise.

👑 AUTHORS 👑

Mark R V Murray. Shoutout to the icon who wrote this one 💅.

Source/version: Debian. Date: February 6, 2002. Manual page: RIJNDAEL(9). That’s the tea — bye bestie 🫶💖