px_xtea.h : XTEA (eXtended Tiny Encryption Algorithm)

Description

Block cipher encryption/decryption algorithm.

File(s):

• utils/inc/px_xtea.h
• utils/src/px_xtea.c

See also

http://en.wikipedia.org/wiki/XTEA

Macros
#define	XTEA_KEY_SIZE_BYTES   16
	Key size in bytes. More...
#define	XTEA_BLOCK_SIZE_BYTES   8
	Data block size in bytes. More...

Functions
void	px_xtea_init (const uint32_t key[4])
	Initialise 128-bit key for encryption/decryption. More...
void	px_xtea_encrypt (uint32_t data[2])
	Encrypt 64-bit data with 128-bit key. More...
size_t	px_xtea_encrypt_data_ecb (const uint8_t *data_in, uint8_t *data_out, size_t nr_of_bytes)
	Encrypt a data buffer using Electronic Codebook (ECB) block cipher operation. More...
void	px_xtea_decrypt (uint32_t data[2])
	Decrypt 64-bit data with 128-bit key. More...
size_t	px_xtea_decrypt_data_ecb (const uint8_t *data_in, uint8_t *data_out, size_t nr_of_bytes)
	Decrypt a data buffer using Electronic Codebook (ECB) block cipher operation. More...

Macro Definition Documentation

XTEA_KEY_SIZE_BYTES

#define XTEA_KEY_SIZE_BYTES   16

Key size in bytes.

Definition at line 46 of file px_xtea.h.

XTEA_BLOCK_SIZE_BYTES

#define XTEA_BLOCK_SIZE_BYTES   8

Data block size in bytes.

Definition at line 48 of file px_xtea.h.

Function Documentation

px_xtea_init()

void px_xtea_init

(

const uint32_t

key[4]

)

Initialise 128-bit key for encryption/decryption.

Parameters

key	4 x 32-bit values

Definition at line 44 of file px_xtea.c.

px_xtea_encrypt()

void px_xtea_encrypt

(

uint32_t

data[2]

)

Encrypt 64-bit data with 128-bit key.

Parameters

data	2 x 32-bit values

Definition at line 54 of file px_xtea.c.

px_xtea_encrypt_data_ecb()

size_t px_xtea_encrypt_data_ecb	(	const uint8_t *	data_in,
		uint8_t *	data_out,
		size_t	nr_of_bytes
	)

Encrypt a data buffer using Electronic Codebook (ECB) block cipher operation.

If the data_in is not an exact multiple of the block size (8 bytes), zero padding is used for the last block. The data_out buffer MUST be a multiple of 8 bytes.

The data can be encrypted in place by setting both the data_in and data_out pointer to the start of the buffer to be encrypted.

Parameters

data_in	Pointer to data buffer to be encrypted
data_out	Pointer to data buffer to contain encrypted data
nr_of_bytes	Number of bytes to encrypt

Returns

size_t Number of bytes encrypted (multiple of block size)

Definition at line 72 of file px_xtea.c.

px_xtea_decrypt()

void px_xtea_decrypt

(

uint32_t

data[2]

)

Decrypt 64-bit data with 128-bit key.

Parameters

data	2 x 32-bit values

Definition at line 112 of file px_xtea.c.

px_xtea_decrypt_data_ecb()

size_t px_xtea_decrypt_data_ecb	(	const uint8_t *	data_in,
		uint8_t *	data_out,
		size_t	nr_of_bytes
	)

Decrypt a data buffer using Electronic Codebook (ECB) block cipher operation.

If the data_in is not an exact multiple of the block size (8 bytes), zero padding is used for the last block. The data_out buffer MUST be a multiple of 8 bytes.

The data can be decrypted in place by setting both the data_in and data_out pointer to the start of the buffer to be decrypted.

Parameters

data_in	Pointer to data buffer to be decrypted
data_out	Pointer to data buffer to contain decrypted data
nr_of_bytes	Number of bytes to decrypt

Returns

size_t Number of bytes decrypted (multiple of block size)

Definition at line 130 of file px_xtea.c.