ciphers.h File Reference

Headers for the packet encryption class. More...

Detailed Description

Headers for the packet encryption class.

They are used to encrypt single packets.

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

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

Mark Essien marke.nosp@m.ssie.nosp@m.n@gma.nosp@m.il.c.nosp@m.om

Definition in file ciphers.h.

#include <stdint.h>
#include "modules.h"

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Data Structures
struct	cipher_context_t
	the context for cipher-operations More...
struct	cipher_interface_st
	BlockCipher-Interface for the Cipher-Algorithms. More...
struct	cipher_t
	basic struct for using block ciphers contains the cipher interface and the context More...
#define	CIPHERS_MAX_KEY_SIZE   16
	the length of keys in bytes More...
#define	CIPHER_MAX_BLOCK_SIZE   16
#define	CIPHER_MAX_CONTEXT_SIZE   1
	Context sizes needed for the different ciphers. More...
#define	CIPHER_ERR_INVALID_KEY_SIZE   -3
#define	CIPHER_ERR_INVALID_LENGTH   -4
#define	CIPHER_ERR_ENC_FAILED   -5
#define	CIPHER_ERR_DEC_FAILED   -6
#define	CIPHER_ERR_BAD_CONTEXT_SIZE   0
	Is returned by the cipher_init functions, if the corresponding algorithm has not been included in the build.
#define	CIPHER_INIT_SUCCESS   1
	Returned by cipher_init upon successful initialization of a cipher.
typedef struct cipher_interface_st	cipher_interface_t
	BlockCipher-Interface for the Cipher-Algorithms.
typedef const cipher_interface_t *	cipher_id_t
	Pointer type to BlockCipher-Interface for the Cipher-Algorithms.
const cipher_id_t	CIPHER_AES
	AES cipher id.
int	cipher_init (cipher_t *cipher, cipher_id_t cipher_id, const uint8_t *key, uint8_t key_size)
	Initialize new cipher state. More...
int	cipher_encrypt (const cipher_t *cipher, const uint8_t *input, uint8_t *output)
	Encrypt data of BLOCK_SIZE length *. More...
int	cipher_decrypt (const cipher_t *cipher, const uint8_t *input, uint8_t *output)
	Decrypt data of BLOCK_SIZE length *. More...
int	cipher_get_block_size (const cipher_t *cipher)
	Get block size of cipher *. More...

Macro Definition Documentation

CIPHER_MAX_CONTEXT_SIZE

#define CIPHER_MAX_CONTEXT_SIZE   1

Context sizes needed for the different ciphers.

Always order by number of bytes descending!!!

aes needs CIPHERS_MAX_KEY_SIZE bytes

Definition at line 59 of file ciphers.h.

CIPHERS_MAX_KEY_SIZE

#define CIPHERS_MAX_KEY_SIZE   16

the length of keys in bytes

As of now AES is the only cipher which supports different key sizes. Here we optimize the CIPHERS_MAX_KEY_SIZE to always have the smallest possible value based on which AES key sizes are used.

Definition at line 44 of file ciphers.h.

Function Documentation

cipher_decrypt()

int cipher_decrypt	(	const cipher_t *	cipher,
		const uint8_t *	input,
		uint8_t *	output
	)

Decrypt data of BLOCK_SIZE length *.

Parameters

cipher	Already initialized cipher struct
input	pointer to input data (of size BLOCKS_SIZE) to decrypt
output	pointer to allocated memory for decrypted data. It has to be of size BLOCK_SIZE

Returns

The result of the decrypt operation of the underlying cipher, which is always 1 in case of success

A negative value for an error

cipher_encrypt()

int cipher_encrypt	(	const cipher_t *	cipher,
		const uint8_t *	input,
		uint8_t *	output
	)

Encrypt data of BLOCK_SIZE length *.

Parameters

cipher	Already initialized cipher struct
input	pointer to input data to encrypt
output	pointer to allocated memory for encrypted data. It has to be of size BLOCK_SIZE

Returns

The result of the encrypt operation of the underlying cipher, which is always 1 in case of success

A negative value for an error

cipher_get_block_size()

int cipher_get_block_size

(

const cipher_t *

cipher

)

Get block size of cipher *.

Parameters

cipher

Already initialized cipher struct

Returns

The cipher's block size (in bytes)

cipher_init()

int cipher_init	(	cipher_t *	cipher,
		cipher_id_t	cipher_id,
		const uint8_t *	key,
		uint8_t	key_size
	)

Initialize new cipher state.

Parameters

cipher	cipher struct to init (already allocated memory)
cipher_id	cipher algorithm id
key	encryption key to use
key_size	length of the encryption 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)

The command may return CIPHER_ERR_INVALID_KEY_SIZE if the key size is not valid.