aes.h

/*********************************************************************
 * Filename:   aes.h
 * Author:     Brad Conte (brad AT bradconte.com)
 * Copyright:
 * Disclaimer: This code is presented "as is" without any guarantees.
 * Details:    Defines the API for the corresponding AES implementation.
 *********************************************************************/

#ifndef AES_H
#define AES_H

/*************************** HEADER FILES ***************************/
#include <stddef.h>

/****************************** MACROS ******************************/
#define AES_BLOCK_SIZE 16  // AES operates on 16 bytes at a time

/**************************** DATA TYPES ****************************/
typedef unsigned char BYTE;  // 8-bit byte
typedef unsigned int WORD;  // 32-bit word, change to "long" for 16-bit machines

/*********************** FUNCTION DECLARATIONS **********************/
///////////////////
// AES
///////////////////
// Key setup must be done before any AES en/de-cryption functions can be used.
void
aes_key_setup(
    const BYTE key[],  // The key, must be 128, 192, or 256 bits
    WORD w[],          // Output key schedule to be used later
    int keysize);      // Bit length of the key, 128, 192, or 256

void
aes_encrypt(
    const BYTE in[],   // 16 bytes of plaintext
    BYTE out[],        // 16 bytes of ciphertext
    const WORD key[],  // From the key setup
    int keysize);      // Bit length of the key, 128, 192, or 256

void
aes_decrypt(
    const BYTE in[],   // 16 bytes of ciphertext
    BYTE out[],        // 16 bytes of plaintext
    const WORD key[],  // From the key setup
    int keysize);      // Bit length of the key, 128, 192, or 256

///////////////////
// AES - CBC
///////////////////
int
aes_encrypt_cbc(
    const BYTE in[],   // Plaintext
    size_t in_len,     // Must be a multiple of AES_BLOCK_SIZE
    BYTE out[],        // Ciphertext, same length as plaintext
    const WORD key[],  // From the key setup
    int keysize,       // Bit length of the key, 128, 192, or 256
    const BYTE iv[]);  // IV, must be AES_BLOCK_SIZE bytes long

// Only output the CBC-MAC of the input.
int
aes_encrypt_cbc_mac(
    const BYTE in[],   // plaintext
    size_t in_len,     // Must be a multiple of AES_BLOCK_SIZE
    BYTE out[],        // Output MAC
    const WORD key[],  // From the key setup
    int keysize,       // Bit length of the key, 128, 192, or 256
    const BYTE iv[]);  // IV, must be AES_BLOCK_SIZE bytes long

///////////////////
// AES - CTR
///////////////////
void
increment_iv(
    BYTE iv[],          // Must be a multiple of AES_BLOCK_SIZE
    int counter_size);  // Bytes of the IV used for counting (low end)

void
aes_encrypt_ctr(
    const BYTE in[],   // Plaintext
    size_t in_len,     // Any byte length
    BYTE out[],        // Ciphertext, same length as plaintext
    const WORD key[],  // From the key setup
    int keysize,       // Bit length of the key, 128, 192, or 256
    const BYTE iv[]);  // IV, must be AES_BLOCK_SIZE bytes long

void
aes_decrypt_ctr(
    const BYTE in[],   // Ciphertext
    size_t in_len,     // Any byte length
    BYTE out[],        // Plaintext, same length as ciphertext
    const WORD key[],  // From the key setup
    int keysize,       // Bit length of the key, 128, 192, or 256
    const BYTE iv[]);  // IV, must be AES_BLOCK_SIZE bytes long

///////////////////
// Test functions
///////////////////
int
aes_test();
int
aes_ecb_test();
int
aes_cbc_test();
int
aes_ctr_test();
int
aes_ccm_test();

#endif  // AES_H