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/*********************************************************************
* 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
///////////////////
// AES - CCM
///////////////////
// Returns True if the input parameters do not violate any constraint.
int aes_encrypt_ccm(const BYTE plaintext[], // IN - Plaintext.
WORD plaintext_len, // IN - Plaintext length.
const BYTE associated_data[], // IN - Associated Data included in authentication, but not encryption.
unsigned short associated_data_len, // IN - Associated Data length in bytes.
const BYTE nonce[], // IN - The Nonce to be used for encryption.
unsigned short nonce_len, // IN - Nonce length in bytes.
BYTE ciphertext[], // OUT - Ciphertext, a concatination of the plaintext and the MAC.
WORD *ciphertext_len, // OUT - The length of the ciphertext, always plaintext_len + mac_len.
WORD mac_len, // IN - The desired length of the MAC, must be 4, 6, 8, 10, 12, 14, or 16.
const BYTE key[], // IN - The AES key for encryption.
int keysize); // IN - The length of the key in bits. Valid values are 128, 192, 256.
// Returns True if the input parameters do not violate any constraint.
// Use mac_auth to ensure decryption/validation was preformed correctly.
// If authentication does not succeed, the plaintext is zeroed out. To overwride
// this, call with mac_auth = NULL. The proper proceedure is to decrypt with
// authentication enabled (mac_auth != NULL) and make a second call to that
// ignores authentication explicitly if the first call failes.
int aes_decrypt_ccm(const BYTE ciphertext[], // IN - Ciphertext, the concatination of encrypted plaintext and MAC.
WORD ciphertext_len, // IN - Ciphertext length in bytes.
const BYTE assoc[], // IN - The Associated Data, required for authentication.
unsigned short assoc_len, // IN - Associated Data length in bytes.
const BYTE nonce[], // IN - The Nonce to use for decryption, same one as for encryption.
unsigned short nonce_len, // IN - Nonce length in bytes.
BYTE plaintext[], // OUT - The plaintext that was decrypted. Will need to be large enough to hold ciphertext_len - mac_len.
WORD *plaintext_len, // OUT - Length in bytes of the output plaintext, always ciphertext_len - mac_len .
WORD mac_len, // IN - The length of the MAC that was calculated.
int *mac_auth, // OUT - TRUE if authentication succeeded, FALSE if it did not. NULL pointer will ignore the authentication.
const BYTE key[], // IN - The AES key for decryption.
int keysize); // IN - The length of the key in BITS. Valid values are 128, 192, 256.
///////////////////
// Test functions
///////////////////
int aes_test();
int aes_ecb_test();
int aes_cbc_test();
int aes_ctr_test();
int aes_ccm_test();
#endif // AES_H
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