aes.h File Reference

Headers for the implementation of the AES cipher-algorithm. More...

Detailed Description

Headers for the implementation of the AES cipher-algorithm.

The default key size is 128 bits. To use a different key size add USEMODULE += crypto_aes_192 and/or USEMODULE += crypto_aes_256 to your Makefile.

If only one key size is needed and that key size is not 128 bits, the 128 bit key size can be disabled with DISABLE_MODULE += crypto_aes_128 as an optimization.

Author

Freie Universitaet Berlin, Computer Systems & Telematics

Nicolai Schmittberger nicol.nosp@m.ai.s.nosp@m.chmit.nosp@m.tber.nosp@m.ger@f.nosp@m.u-be.nosp@m.rlin..nosp@m.de

Fabrice Bellard

Zakaria Kasmi zkasm.nosp@m.i@in.nosp@m.f.fu-.nosp@m.berl.nosp@m.in.de

Definition in file aes.h.

#include <stdint.h>
#include "crypto/ciphers.h"

Include dependency graph for aes.h:

Go to the source code of this file.

Data Structures
struct	aes_context_t
	the cipher_context_t-struct adapted for AES More...

Functions
int	aes_init (cipher_context_t *context, const uint8_t *key, uint8_t keySize)
	initializes the AES Cipher-algorithm with the passed parameters
int	aes_encrypt (const cipher_context_t *context, const uint8_t *plain_block, uint8_t *cipher_block)
	encrypts one plainBlock-block and saves the result in cipherblock.
int	aes_decrypt (const cipher_context_t *context, const uint8_t *cipher_block, uint8_t *plain_block)
	decrypts one cipher-block and saves the plain-block in plainBlock.
#define	GETU32(pt)
#define	PUTU32(ct, st)
#define	AES_MAXNR   14
#define	AES_BLOCK_SIZE   16
typedef uint32_t	u32
typedef uint16_t	u16
typedef uint8_t	u8

AES key sizes
#define	AES_KEY_SIZE_128   16
#define	AES_KEY_SIZE_192   24
#define	AES_KEY_SIZE_256   32

Macro Definition Documentation

AES_BLOCK_SIZE

#define AES_BLOCK_SIZE   16

Definition at line 52 of file aes.h.

AES_KEY_SIZE_128

#define AES_KEY_SIZE_128   16

Definition at line 58 of file aes.h.

AES_KEY_SIZE_192

#define AES_KEY_SIZE_192   24

Definition at line 59 of file aes.h.

AES_KEY_SIZE_256

#define AES_KEY_SIZE_256   32

Definition at line 60 of file aes.h.

AES_MAXNR

#define AES_MAXNR   14

Definition at line 51 of file aes.h.

GETU32

#define GETU32

(

pt

)

Value:

                     (((u32)(pt)[0] << 24) ^ ((u32)(pt)[1] << 16) ^ \
                     ((u32)(pt)[2] <<  8) ^ ((u32)(pt)[3]))

Definition at line 44 of file aes.h.

PUTU32

#define PUTU32	(		ct,
			st
	)

Value:

                          { (ct)[0] = (u8)((st) >> 24); \
                          (ct)[1] = (u8)((st) >> 16); \
                          (ct)[2] = (u8)((st) >>  8); \
                          (ct)[3] = (u8)(st); }

Definition at line 46 of file aes.h.

Typedef Documentation

u16

typedef uint16_t u16

Definition at line 41 of file aes.h.

u32

typedef uint32_t u32

Definition at line 40 of file aes.h.

u8

typedef uint8_t u8

Definition at line 42 of file aes.h.

Function Documentation

aes_decrypt()

int aes_decrypt	(	const cipher_context_t *	context,
		const uint8_t *	cipher_block,
		uint8_t *	plain_block
	)

decrypts one cipher-block and saves the plain-block in plainBlock.

decrypts one blocksize long block of ciphertext pointed to by cipherBlock to one blocksize long block of plaintext and stores the plaintext in the memory-area pointed to by plainBlock

Parameters

context	the cipher_context_t-struct to use for this decryption
cipher_block	a pointer to the ciphertext-block (of size blocksize) to be decrypted
plain_block	a pointer to the place where the decrypted plaintext will be stored

Returns

1 on success

A negative value if the cipher key cannot be expanded with the AES key schedule

aes_encrypt()

int aes_encrypt	(	const cipher_context_t *	context,
		const uint8_t *	plain_block,
		uint8_t *	cipher_block
	)

encrypts one plainBlock-block and saves the result in cipherblock.

encrypts one blocksize long block of plaintext pointed to by plainBlock to one blocksize long block of ciphertext which will be written to the the memory-area pointed to by cipherBlock

Parameters

context	the cipher_context_t-struct to use for this encryption
plain_block	a pointer to the plaintext-block (of size blocksize)
cipher_block	a pointer to the place where the ciphertext will be stored

Returns

1 on success

A negative value if the cipher key cannot be expanded with the AES key schedule

aes_init()

int aes_init	(	cipher_context_t *	context,
		const uint8_t *	key,
		uint8_t	keySize
	)

initializes the AES Cipher-algorithm with the passed parameters

Parameters

context	the cipher_context_t-struct to save the initialization of the cipher in
keySize	the size of the key Must be 16, since this implementation does not support key lengths of 24 or 32 bytes
key	a pointer to the key

Returns

CIPHER_INIT_SUCCESS if the initialization was successful.

CIPHER_ERR_BAD_CONTEXT_SIZE if CIPHER_MAX_CONTEXT_SIZE has not been defined (which means that the cipher has not been included in the build)