random.c

开发源代码的CPU卡的COS源程序。

/* ============================================================================
   Project Name : jayaCard
   Module Name  : proto/bios/crypto/random.c
   Version : $Id: random.c,v 1.14 2004/01/11 09:56:30 dgil Exp $

	Description: secure 8 bytes random challenging

    The Original Code is jayaCard code.

    The Initial Developer of the Original Code is Gilles Dumortier.

	Portions created by the Initial Developer are Copyright (C) 2002-2004 the
    Initial Developer. All Rights Reserved.

    Contributor(s):

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; see http://www.gnu.org/licenses/gpl.html

   History Rev	Description
   012603 dgil	wrote it from scratch
   ============================================================================
*/

#include "precomp.h"

/* ============================================================================
	__bios_random()

	Fill a buffer of 8 bytes with random values. This function must be very
	secure.

	Algo:
		start:
			init values
		loop:
			extract two bits of a hardware random (HAL_RANDOM_BYTE() call)
			if 10 or 01, use these two bits to generate one good final bit
			loop: until u.bBlock[] has been filled
		end:
			if same value in all u.bBlock[] cell re-start:

	secure: use global semaphore
   ========================================================================= */

#ifdef HALCFG_DEV_RANDOM_NULL

/* special version returning always 00000...000 */
void __bios_random(void)
{
	HAL_HARDWARE(HARDWARE_RNG);
	gGlobalSem++;

	u.bBlock[JAYA_BCRYPTO_RANDOM0+0] = 0x00;
	u.bBlock[JAYA_BCRYPTO_RANDOM0+1] = 0x00;
	u.bBlock[JAYA_BCRYPTO_RANDOM0+2] = 0x00;
	u.bBlock[JAYA_BCRYPTO_RANDOM0+3] = 0x00;
	u.bBlock[JAYA_BCRYPTO_RANDOM0+4] = 0x00;
	u.bBlock[JAYA_BCRYPTO_RANDOM0+5] = 0x00;
	u.bBlock[JAYA_BCRYPTO_RANDOM0+6] = 0x00;
	u.bBlock[JAYA_BCRYPTO_RANDOM0+7] = 0x00;

	gGlobalSem++;
	HAL_HARDWARE(HARDWARE_NONE);
}

#else
void __bios_random(void)
{
	jbyte 	nbyte;
	jbyte	vbyte;
	jbyte	vbit;

	HAL_HARDWARE(HARDWARE_RNG);
	gGlobalSem++;

start:
	nbyte = 0;
	vbit = 1;

	do {
		vbyte = HAL_RANDOM_BYTE();
		do {
			if ((vbyte&0x3)==0x01) {
				/* extract a bit ONE */
				u.bBlock[JAYA_BCRYPTO_RANDOM0+nbyte] |= vbit;
				/* next bit ? */
				if (vbit==0x80) {
					/* next byte ? */
					if (nbyte==7) goto end;
					/* next byte ! */
					nbyte++;
					vbit = 1;
				} else {
					/* next bit ! */
					vbit<<=1;
				}
			} else if ((vbyte&0x3)==0x02) {
				/* extract a bit ZERO */
				u.bBlock[JAYA_BCRYPTO_RANDOM0+nbyte] &= ~vbit;
				/* next bit ? */
				if (vbit==0x80) {
					/* next byte ? */
					if (nbyte==7) goto end;
					/* next byte ! */
					nbyte++;
					vbit = 1;
				} else {
					/* next bit ! */
					vbit<<=1;
				}
			}
			/* next two bits for extraction */
			vbyte>>=2;
		} while (vbyte!=0);
		/* endless waiting nbyte>7 to jump outside with a bad goto ;-) */
	} while (1);

end:
	/* strange de-generate(d) case !? */
	if ( (u.bBlock[JAYA_BCRYPTO_RANDOM0+0]==u.bBlock[JAYA_BCRYPTO_RANDOM0+1]) && (u.bBlock[JAYA_BCRYPTO_RANDOM0+1]==u.bBlock[JAYA_BCRYPTO_RANDOM0+2]) && (u.bBlock[JAYA_BCRYPTO_RANDOM0+2]==u.bBlock[JAYA_BCRYPTO_RANDOM0+3]) &&
	     (u.bBlock[JAYA_BCRYPTO_RANDOM0+3]==u.bBlock[JAYA_BCRYPTO_RANDOM0+4]) && (u.bBlock[JAYA_BCRYPTO_RANDOM0+4]==u.bBlock[JAYA_BCRYPTO_RANDOM0+5]) && (u.bBlock[JAYA_BCRYPTO_RANDOM0+5]==u.bBlock[JAYA_BCRYPTO_RANDOM0+6]) &&
		 (u.bBlock[JAYA_BCRYPTO_RANDOM0+6]==u.bBlock[JAYA_BCRYPTO_RANDOM0+7]) ) goto start;

	/* ok. Enough to have a good feeling ... */
	gGlobalSem++;
	HAL_HARDWARE(HARDWARE_NONE);
}
#endif

/* =========================================================================
	That's all folks !
   ========================================================================= */