AES Class Reference

#include <AES.h>

Public Member Functions
	AES ()
	AES constructor. More...
byte	set_key (byte key[], int keylen)
void	clean ()
void	copy_n_bytes (byte *AESt, byte *src, byte n)
byte	encrypt (byte plain[N_BLOCK], byte cipher[N_BLOCK])
byte	cbc_encrypt (byte *plain, byte *cipher, int n_block, byte iv[N_BLOCK])
byte	cbc_encrypt (byte *plain, byte *cipher, int n_block)
byte	decrypt (byte cipher[N_BLOCK], byte plain[N_BLOCK])
byte	cbc_decrypt (byte *cipher, byte *plain, int n_block, byte iv[N_BLOCK])
byte	cbc_decrypt (byte *cipher, byte *plain, int n_block)
void	set_IV (unsigned long long int IVCl)
void	iv_inc ()
int	get_size ()
void	set_size (int sizel)
void	get_IV (byte *out)
void	calc_size_n_pad (int p_size)
void	padPlaintext (void *in, byte *out)
bool	CheckPad (byte *in, int size)
void	printArray (byte output[], bool p_pad=true)
void	printArray (byte output[], int sizel)
void	do_aes_encrypt (byte *plain, int size_p, byte *cipher, byte *key, int bits, byte ivl[N_BLOCK])
void	do_aes_encrypt (byte *plain, int size_p, byte *cipher, byte *key, int bits)
void	do_aes_decrypt (byte *cipher, int size_c, byte *plain, byte *key, int bits, byte ivl[N_BLOCK])
void	do_aes_decrypt (byte *cipher, int size_c, byte *plain, byte *key, int bits)
double	millis ()

Private Attributes
int	round
byte	key_sched [KEY_SCHEDULE_BYTES]
unsigned long long int	IVC
byte	iv [16]
int	pad
int	size
timeval	tv
byte	arr_pad [15] = { 0x01,0x02,0x03,0x04,0x05,0x06,0x07,0x08,0x09,0x0a,0x0b,0x0c,0x0d,0x0e,0x0f }

Detailed Description

Examples:

aes.cpp, and test_vectors.cpp.

Constructor & Destructor Documentation

AES::AES

(

)

AES constructor.

This function initialized an instance of AES.

Member Function Documentation

byte AES::set_key	(	byte	key[],
		int	keylen
	)

Set the cipher key for the pre-keyed version.

Parameters

key[]	pointer to the key string.
keylen	Integer that indicates the length of the key.

Note

NOTE: If the length_type used for the key length is an unsigned 8-bit character, a key length of 256 bits must be entered as a length in bytes (valid inputs are hence 128, 192, 16, 24 and 32).

Examples:

test_vectors.cpp.

void AES::clean

(

)

clean up subkeys after use.

void AES::copy_n_bytes	(	byte *	AESt,
		byte *	src,
		byte	n
	)

copying and xoring utilities.

Parameters

*AESt	byte pointer of the AEStination array.
*src	byte pointer of the source array.
n	byte, indicating the sizeof the bytes to be copied.

Note

this is an alternative for memcpy(void *s1,const void *s2, site_t n), i have not updated the function in the implementation yet, but it is considered a future plan.

Examples:

test_vectors.cpp.

byte AES::encrypt	(	byte	plain[N_BLOCK],
		byte	cipher[N_BLOCK]
	)

Encrypt a single block of 16 bytes .

Parameters

plain[N_BLOCK]	Array of the plaintext.
cipher[N_BLOCK]	Array of the ciphertext.

Note

The N_BLOCK is defined in AES_config.h as,

#define N_ROW                   4
     #define N_COL                   4
     #define N_BLOCK   (N_ROW * N_COL)

Changed to that will change the Block_size. 0 if SUCCESS or -1 if FAILURE

Examples:

test_vectors.cpp.

byte AES::cbc_encrypt	(	byte *	plain,
		byte *	cipher,
		int	n_block,
		byte	iv[N_BLOCK]
	)

CBC encrypt a number of blocks (input and return an IV).

Parameters

*plain	Pointer, points to the plaintex.
*cipher	Pointer, points to the ciphertext that will be created.
n_block	integer, indicated the number of blocks to be ciphered.
iv[N_BLOCK]	byte Array that holds the IV (initialization vector). 0 if SUCCESS or -1 if FAILURE

byte AES::cbc_encrypt	(	byte *	plain,
		byte *	cipher,
		int	n_block
	)

CBC encrypt a number of blocks (input and return an IV).

Parameters

*plain	Pointer, points to the plaintex.
*cipher	Pointer, points to the ciphertext that will be created.
n_block	integer, indicated the number of blocks to be ciphered. 0 if SUCCESS or -1 if FAILURE

byte AES::decrypt	(	byte	cipher[N_BLOCK],
		byte	plain[N_BLOCK]
	)

Decrypt a single block of 16 bytes

Parameters

cipher[N_BLOCK]	Array of the ciphertext.
plain[N_BLOCK]	Array of the plaintext.

Note

The N_BLOCK is defined in AES_config.h as,

#define N_ROW                   4
     #define N_COL                   4
     #define N_BLOCK   (N_ROW * N_COL)

Changed to that will change the Block_size. 0 if SUCCESS or -1 if FAILURE

Examples:

test_vectors.cpp.

byte AES::cbc_decrypt	(	byte *	cipher,
		byte *	plain,
		int	n_block,
		byte	iv[N_BLOCK]
	)

CBC decrypt a number of blocks (input and return an IV)

Parameters

*cipher	Pointer, points to the ciphertext that will be created.
*plain	Pointer, points to the plaintex.
n_block	integer, indicated the number of blocks to be ciphered.
iv[N_BLOCK]	byte Array that holds the IV (initialization vector). 0 if SUCCESS or -1 if FAILURE

byte AES::cbc_decrypt	(	byte *	cipher,
		byte *	plain,
		int	n_block
	)

CBC decrypt a number of blocks (input and return an IV)

Parameters

*cipher	Pointer, points to the ciphertext that will be created.
*plain	Pointer, points to the plaintex.
n_block	integer, indicated the number of blocks to be ciphered. 0 if SUCCESS or -1 if FAILURE

void AES::set_IV

(

unsigned long long int

IVCl

)

Sets IV (initialization vector) and IVC (IV counter). This function changes the ivc and iv variables needed for AES.

Parameters

IVCl	int or hex value of iv , ex. 0x0000000000000001

Note

example:

unsigned long long int my_iv = 01234567; 

void AES::iv_inc

(

)

increase the iv (initialization vector) and IVC (IV counter) by 1

This function increased the VI by one step in order to have a different IV each time

int AES::get_size

(

)

Getter method for size

This function return the size

Returns

an integer, that is the size of the of the padded plaintext, thus, the size of the ciphertext.

Examples:

aes.cpp.

void AES::set_size

(

int

sizel

)

Setter method for size

This function sets the size of the plaintext+pad

void AES::get_IV

(

byte *

out

)

Getter method for IV

This function return the IV

Parameters

out	byte pointer that gets the IV.

Returns

none, the IV is writed to the out pointer.

Examples:

aes.cpp.

void AES::calc_size_n_pad

(

int

p_size

)

Calculates the size of the plaintext and the padding.

Calculates the size of theplaintext with the padding and the size of the padding needed. Moreover it stores them in their class variables.

Parameters

p_size

the size of the byte array ex sizeof(plaintext)

void AES::padPlaintext	(	void *	in,
		byte *	out
	)

Pads the plaintext

This function pads the plaintext and returns an char array with the plaintext and the padding in order for the plaintext to be compatible with 16bit size blocks required by AES

Parameters

in	the string of the plaintext in a byte array
out	The string of the out array.

Returns

no return, The padded plaintext is stored in the out pointer.

bool AES::CheckPad	(	byte *	in,
		int	size
	)

Check the if the padding is correct.

This functions checks the padding of the plaintext.

Parameters

in	the string of the plaintext in a byte array
size	the size of the string

Returns

true if correct / false if not

void AES::printArray	(	byte	output[],
		bool	p_pad = true
	)

Prints the array given.

This function prints the given array and pad, It is mainlly used for debugging purpuses or to output the string.

Parameters

output[]	the string of the text in a byte array
p_pad	optional, used to print with out the padding characters

Examples:

aes.cpp.

void AES::printArray	(	byte	output[],
		int	sizel
	)

Prints the array given.

This function prints the given array in Hexadecimal.

Parameters

output[]	the string of the text in a byte array
sizel	the size of the array.

void AES::do_aes_encrypt	(	byte *	plain,
		int	size_p,
		byte *	cipher,
		byte *	key,
		int	bits,
		byte	ivl[N_BLOCK]
	)

User friendly implementation of AES-CBC encryption.

Parameters

*plain	pointer to the plaintext
size_p	size of the plaintext
*cipher	pointer to the ciphertext
*key	pointer to the key that will be used.
bits	bits of the encryption/decrpytion
ivl[N_BLOCK]	the initialization vector IV that will be used for encryption.

Note

The key will be stored in class variable.

Examples:

aes.cpp.

void AES::do_aes_encrypt	(	byte *	plain,
		int	size_p,
		byte *	cipher,
		byte *	key,
		int	bits
	)

User friendly implementation of AES-CBC encryption.

Parameters

*plain	pointer to the plaintext
size_p	size of the plaintext
*cipher	pointer to the ciphertext
*key	pointer to the key that will be used.
bits	bits of the encryption/decrpytion

Note

The key will be stored in class variable.

void AES::do_aes_decrypt	(	byte *	cipher,
		int	size_c,
		byte *	plain,
		byte *	key,
		int	bits,
		byte	ivl[N_BLOCK]
	)

User friendly implementation of AES-CBC decryption.

Parameters

*cipher	pointer to the ciphertext
size_c	size of the ciphertext
*plain	pointer to the plaintext
*key	pointer to the key that will be used.
bits	bits of the encryption/decrpytion
ivl[N_BLOCK]	the initialization vector IV that will be used for decryption.

Note

The key will be stored in class variable.

void AES::do_aes_decrypt	(	byte *	cipher,
		int	size_c,
		byte *	plain,
		byte *	key,
		int	bits
	)

User friendly implementation of AES-CBC decryption.

Parameters

*cipher	pointer to the ciphertext
size_c	size of the ciphertext
*plain	pointer to the plaintext
*key	pointer to the key that will be used.
bits	bits of the encryption/decrpytion

Note

The key will be stored in class variable.

double AES::millis

(

)

used in linux in order to retrieve the time in milliseconds.

Returns

returns the milliseconds in a double format.

Member Data Documentation

int AES::round

private

holds the number of rounds to be used.

byte AES::key_sched[KEY_SCHEDULE_BYTES]

private

holds the pre-computed key for the encryption/decrpytion.

unsigned long long int AES::IVC

private

holds the initialization vector counter in numerical format.

byte AES::iv[16]

private

holds the initialization vector that will be used in the cipher.

int AES::pad

private

holds the size of the padding.

int AES::size

private

hold the size of the plaintext to be ciphered

timeval AES::tv

private

holds the time value on linux

byte AES::arr_pad = { 0x01,0x02,0x03,0x04,0x05,0x06,0x07,0x08,0x09,0x0a,0x0b,0x0c,0x0d,0x0e,0x0f }

private

holds the hexadecimal padding values on linux

holds the hexadecimal padding values