roboot/boot/xtea.c File Reference

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Detailed Description

XTEA cipher for ROBOOT.

License:

ROBOOT ver. 0.1.0 - Copyright (C) 2010 AGH UST

This file is part of the ROBOOT (RObus BOOTloader) project. ROBOOT is developed at the Department of Electronics, AGH University of Science and Technology in Krakow, Poland.

The ROBOOT project uses dual-licensing. You can use it for free for non-commercial, open source projects. See license.txt for details or visit project home page at http://www.wsn.agh.edu.pl/?q=roboot

THIS SOFTWARE IS PROVIDED 'AS IS'. NO WARRANTIES, WHETHER EXPRESS, IMPLIED OR STATUTORY, INCLUDING, BUT NOT LIMITED TO, IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE APPLY TO THIS SOFTWARE. AGH UST SHALL NOT, IN ANY CIRCUMSTANCES, BE LIABLE FOR SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, FOR ANY REASON WHATSOEVER.

Author:

Artur Lipowski

Purpose:

ROBOOT

Compiler:

GCC

Hardware:

independent

Documented in:

doxygen

Comments:

Definition in file xtea.c.

#include "xtea.h"

Go to the source code of this file.

Defines
#define	STORE32L(x, y)
#define	LOAD32L(x, y)
Functions
void	XteaSetup (const uint8_t *key, const uint8_t *iv, XteaStateKey_T *skey)
void	XteaRestart (XteaStateKey_T *skey)
void	XteaEncrypt (const uint8_t *pt, uint8_t *ct, uint32_t len, XteaStateKey_T *skey)
void	XteaDecrypt (const uint8_t *ct, uint8_t *pt, uint32_t len, XteaStateKey_T *skey)

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Define Documentation

#define STORE32L	(	x,
		y		)

Value:

do {                                    \
        (y)[3] = (uint8_t)(((x)>>24)&255);  \
        (y)[2] = (uint8_t)(((x)>>16)&255);  \
        (y)[1] = (uint8_t)(((x)>>8)&255);   \
        (y)[0] = (uint8_t)((x)&255);        \
    } while (0)

Definition at line 32 of file xtea.c.

#define LOAD32L	(	x,
		y		)

Value:

do {                                        \
        (x) = ((uint32_t)((y)[3] & 255)<<24) |  \
              ((uint32_t)((y)[2] & 255)<<16) |  \
              ((uint32_t)((y)[1] & 255)<<8)  |  \
              ((uint32_t)((y)[0] & 255));       \
    } while (0)

Definition at line 40 of file xtea.c.

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Function Documentation

void XteaSetup	(	const uint8_t *	key,
		const uint8_t *	iv,
		XteaStateKey_T *	skey
	)

Initializes XTEA encryption algorithm API. Because actual data and state needed for encryption/decryption is stored into separate space (skey) then it is possible to perform many operations simultaneously. It is safe to call this function many times for given skey data. Function does not use dynamic memory allocation.

Parameters:

	key	a key used for encryption and decryption
	iv	a initialization vector for algorithm (if NULL then it will be not used)
	skey	a pointer to internally used data

Definition at line 55 of file xtea.c.

References XteaRestart().

void XteaRestart

(

XteaStateKey_T *

skey

)

Reinitializes XTEA encryption algorithm API. This function can be used for subsequent encryption/decryption of data using the same key.

Parameters:

skey

a pointer to internally used data (it have to be initialized previously by XteaSetup function)

Definition at line 96 of file xtea.c.

Referenced by XteaSetup().

void XteaEncrypt	(	const uint8_t *	pt,
		uint8_t *	ct,
		uint32_t	len,
		XteaStateKey_T *	skey
	)

Encrypts a block of text with XTEA algo.

Parameters:

	pt	the input plain text
	ct	the output cipher text
	len	the length of data for encryption
	skey	a pointer to internally used data

Definition at line 113 of file xtea.c.

Referenced by XteaDecrypt().

void XteaDecrypt	(	const uint8_t *	ct,
		uint8_t *	pt,
		uint32_t	len,
		XteaStateKey_T *	skey
	)

Decrypts a block of text with XTEA algo.

Parameters:

	ct	the output cipher text
	pt	the input plain text
	len	the length of data for encryption
	skey	a pointer to internally used data

Definition at line 133 of file xtea.c.

References XteaEncrypt().