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/*	$Id: acss.c,v 1.4 2006/07/24 04:51:01 djm Exp $ */

/*

 * Copyright (c) 2004 The OpenBSD project

 *

 * Permission to use, copy, modify, and distribute this software for any

 * purpose with or without fee is hereby granted, provided that the above

 * copyright notice and this permission notice appear in all copies.

 *

 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES

 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF

 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR

 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES

 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN

 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF

 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

 */

#include "includes.h"

#include <string.h>

#include <openssl/evp.h>

#if !defined(EVP_CTRL_SET_ACSS_MODE) && (OPENSSL_VERSION_NUMBER >= 0x00906000L)

#include "acss.h"

/* decryption sbox */

static unsigned char sboxdec[] = {

	0x33, 0x73, 0x3b, 0x26, 0x63, 0x23, 0x6b, 0x76,

	0x3e, 0x7e, 0x36, 0x2b, 0x6e, 0x2e, 0x66, 0x7b,

	0xd3, 0x93, 0xdb, 0x06, 0x43, 0x03, 0x4b, 0x96,

	0xde, 0x9e, 0xd6, 0x0b, 0x4e, 0x0e, 0x46, 0x9b,

	0x57, 0x17, 0x5f, 0x82, 0xc7, 0x87, 0xcf, 0x12,

	0x5a, 0x1a, 0x52, 0x8f, 0xca, 0x8a, 0xc2, 0x1f,

	0xd9, 0x99, 0xd1, 0x00, 0x49, 0x09, 0x41, 0x90,

	0xd8, 0x98, 0xd0, 0x01, 0x48, 0x08, 0x40, 0x91,

	0x3d, 0x7d, 0x35, 0x24, 0x6d, 0x2d, 0x65, 0x74,

	0x3c, 0x7c, 0x34, 0x25, 0x6c, 0x2c, 0x64, 0x75,

	0xdd, 0x9d, 0xd5, 0x04, 0x4d, 0x0d, 0x45, 0x94,

	0xdc, 0x9c, 0xd4, 0x05, 0x4c, 0x0c, 0x44, 0x95,

	0x59, 0x19, 0x51, 0x80, 0xc9, 0x89, 0xc1, 0x10,

	0x58, 0x18, 0x50, 0x81, 0xc8, 0x88, 0xc0, 0x11,

	0xd7, 0x97, 0xdf, 0x02, 0x47, 0x07, 0x4f, 0x92,

	0xda, 0x9a, 0xd2, 0x0f, 0x4a, 0x0a, 0x42, 0x9f,

	0x53, 0x13, 0x5b, 0x86, 0xc3, 0x83, 0xcb, 0x16,

	0x5e, 0x1e, 0x56, 0x8b, 0xce, 0x8e, 0xc6, 0x1b,

	0xb3, 0xf3, 0xbb, 0xa6, 0xe3, 0xa3, 0xeb, 0xf6,

	0xbe, 0xfe, 0xb6, 0xab, 0xee, 0xae, 0xe6, 0xfb,

	0x37, 0x77, 0x3f, 0x22, 0x67, 0x27, 0x6f, 0x72,

	0x3a, 0x7a, 0x32, 0x2f, 0x6a, 0x2a, 0x62, 0x7f,

	0xb9, 0xf9, 0xb1, 0xa0, 0xe9, 0xa9, 0xe1, 0xf0,

	0xb8, 0xf8, 0xb0, 0xa1, 0xe8, 0xa8, 0xe0, 0xf1,

	0x5d, 0x1d, 0x55, 0x84, 0xcd, 0x8d, 0xc5, 0x14,

	0x5c, 0x1c, 0x54, 0x85, 0xcc, 0x8c, 0xc4, 0x15,

	0xbd, 0xfd, 0xb5, 0xa4, 0xed, 0xad, 0xe5, 0xf4,

	0xbc, 0xfc, 0xb4, 0xa5, 0xec, 0xac, 0xe4, 0xf5,

	0x39, 0x79, 0x31, 0x20, 0x69, 0x29, 0x61, 0x70,

	0x38, 0x78, 0x30, 0x21, 0x68, 0x28, 0x60, 0x71,

	0xb7, 0xf7, 0xbf, 0xa2, 0xe7, 0xa7, 0xef, 0xf2,

	0xba, 0xfa, 0xb2, 0xaf, 0xea, 0xaa, 0xe2, 0xff

};

/* encryption sbox */

static unsigned char sboxenc[] = {

	0x33, 0x3b, 0x73, 0x15, 0x53, 0x5b, 0x13, 0x75,

	0x3d, 0x35, 0x7d, 0x1b, 0x5d, 0x55, 0x1d, 0x7b,

	0x67, 0x6f, 0x27, 0x81, 0xc7, 0xcf, 0x87, 0x21,

	0x69, 0x61, 0x29, 0x8f, 0xc9, 0xc1, 0x89, 0x2f,

	0xe3, 0xeb, 0xa3, 0x05, 0x43, 0x4b, 0x03, 0xa5,

	0xed, 0xe5, 0xad, 0x0b, 0x4d, 0x45, 0x0d, 0xab,

	0xea, 0xe2, 0xaa, 0x00, 0x4a, 0x42, 0x0a, 0xa0,

	0xe8, 0xe0, 0xa8, 0x02, 0x48, 0x40, 0x08, 0xa2,

	0x3e, 0x36, 0x7e, 0x14, 0x5e, 0x56, 0x1e, 0x74,

	0x3c, 0x34, 0x7c, 0x16, 0x5c, 0x54, 0x1c, 0x76,

	0x6a, 0x62, 0x2a, 0x80, 0xca, 0xc2, 0x8a, 0x20,

	0x68, 0x60, 0x28, 0x82, 0xc8, 0xc0, 0x88, 0x22,

	0xee, 0xe6, 0xae, 0x04, 0x4e, 0x46, 0x0e, 0xa4,

	0xec, 0xe4, 0xac, 0x06, 0x4c, 0x44, 0x0c, 0xa6,

	0xe7, 0xef, 0xa7, 0x01, 0x47, 0x4f, 0x07, 0xa1,

	0xe9, 0xe1, 0xa9, 0x0f, 0x49, 0x41, 0x09, 0xaf,

	0x63, 0x6b, 0x23, 0x85, 0xc3, 0xcb, 0x83, 0x25,

	0x6d, 0x65, 0x2d, 0x8b, 0xcd, 0xc5, 0x8d, 0x2b,

	0x37, 0x3f, 0x77, 0x11, 0x57, 0x5f, 0x17, 0x71,

	0x39, 0x31, 0x79, 0x1f, 0x59, 0x51, 0x19, 0x7f,

	0xb3, 0xbb, 0xf3, 0x95, 0xd3, 0xdb, 0x93, 0xf5,

	0xbd, 0xb5, 0xfd, 0x9b, 0xdd, 0xd5, 0x9d, 0xfb,

	0xba, 0xb2, 0xfa, 0x90, 0xda, 0xd2, 0x9a, 0xf0,

	0xb8, 0xb0, 0xf8, 0x92, 0xd8, 0xd0, 0x98, 0xf2,

	0x6e, 0x66, 0x2e, 0x84, 0xce, 0xc6, 0x8e, 0x24,

	0x6c, 0x64, 0x2c, 0x86, 0xcc, 0xc4, 0x8c, 0x26,

	0x3a, 0x32, 0x7a, 0x10, 0x5a, 0x52, 0x1a, 0x70,

	0x38, 0x30, 0x78, 0x12, 0x58, 0x50, 0x18, 0x72,

	0xbe, 0xb6, 0xfe, 0x94, 0xde, 0xd6, 0x9e, 0xf4,

	0xbc, 0xb4, 0xfc, 0x96, 0xdc, 0xd4, 0x9c, 0xf6,

	0xb7, 0xbf, 0xf7, 0x91, 0xd7, 0xdf, 0x97, 0xf1,

	0xb9, 0xb1, 0xf9, 0x9f, 0xd9, 0xd1, 0x99, 0xff

};

static unsigned char reverse[] = {

	0x00, 0x80, 0x40, 0xc0, 0x20, 0xa0, 0x60, 0xe0,

	0x10, 0x90, 0x50, 0xd0, 0x30, 0xb0, 0x70, 0xf0,

	0x08, 0x88, 0x48, 0xc8, 0x28, 0xa8, 0x68, 0xe8,

	0x18, 0x98, 0x58, 0xd8, 0x38, 0xb8, 0x78, 0xf8,

	0x04, 0x84, 0x44, 0xc4, 0x24, 0xa4, 0x64, 0xe4,

	0x14, 0x94, 0x54, 0xd4, 0x34, 0xb4, 0x74, 0xf4,

	0x0c, 0x8c, 0x4c, 0xcc, 0x2c, 0xac, 0x6c, 0xec,

	0x1c, 0x9c, 0x5c, 0xdc, 0x3c, 0xbc, 0x7c, 0xfc,

	0x02, 0x82, 0x42, 0xc2, 0x22, 0xa2, 0x62, 0xe2,

	0x12, 0x92, 0x52, 0xd2, 0x32, 0xb2, 0x72, 0xf2,

	0x0a, 0x8a, 0x4a, 0xca, 0x2a, 0xaa, 0x6a, 0xea,

	0x1a, 0x9a, 0x5a, 0xda, 0x3a, 0xba, 0x7a, 0xfa,

	0x06, 0x86, 0x46, 0xc6, 0x26, 0xa6, 0x66, 0xe6,

	0x16, 0x96, 0x56, 0xd6, 0x36, 0xb6, 0x76, 0xf6,

	0x0e, 0x8e, 0x4e, 0xce, 0x2e, 0xae, 0x6e, 0xee,

	0x1e, 0x9e, 0x5e, 0xde, 0x3e, 0xbe, 0x7e, 0xfe,

	0x01, 0x81, 0x41, 0xc1, 0x21, 0xa1, 0x61, 0xe1,

	0x11, 0x91, 0x51, 0xd1, 0x31, 0xb1, 0x71, 0xf1,

	0x09, 0x89, 0x49, 0xc9, 0x29, 0xa9, 0x69, 0xe9,

	0x19, 0x99, 0x59, 0xd9, 0x39, 0xb9, 0x79, 0xf9,

	0x05, 0x85, 0x45, 0xc5, 0x25, 0xa5, 0x65, 0xe5,

	0x15, 0x95, 0x55, 0xd5, 0x35, 0xb5, 0x75, 0xf5,

	0x0d, 0x8d, 0x4d, 0xcd, 0x2d, 0xad, 0x6d, 0xed,

	0x1d, 0x9d, 0x5d, 0xdd, 0x3d, 0xbd, 0x7d, 0xfd,

	0x03, 0x83, 0x43, 0xc3, 0x23, 0xa3, 0x63, 0xe3,

	0x13, 0x93, 0x53, 0xd3, 0x33, 0xb3, 0x73, 0xf3,

	0x0b, 0x8b, 0x4b, 0xcb, 0x2b, 0xab, 0x6b, 0xeb,

	0x1b, 0x9b, 0x5b, 0xdb, 0x3b, 0xbb, 0x7b, 0xfb,

	0x07, 0x87, 0x47, 0xc7, 0x27, 0xa7, 0x67, 0xe7,

	0x17, 0x97, 0x57, 0xd7, 0x37, 0xb7, 0x77, 0xf7,

	0x0f, 0x8f, 0x4f, 0xcf, 0x2f, 0xaf, 0x6f, 0xef,

	0x1f, 0x9f, 0x5f, 0xdf, 0x3f, 0xbf, 0x7f, 0xff

};

/*

 * Two linear feedback shift registers are used:

 *

 * lfsr17:  polynomial of degree 17, primitive modulo 2 (listed in Schneier)

 *          x^15 + x + 1

 * lfsr25:  polynomial of degree 25, not know if primitive modulo 2

 *          x^13 + x^5 + x^4 + x^1 + 1

 *

 * Output bits are discarded, instead the feedback bits are added to produce

 * the cipher stream.  Depending on the mode, feedback bytes may be inverted

 * bit-wise before addition.

 *

 * The lfsrs are seeded with bytes from the raw key:

 *

 * lfsr17:  byte 0[0:7] at bit 9

 *          byte 1[0:7] at bit 0

 *

 * lfsr25:  byte 2[0:4] at bit 16

 *          byte 2[5:7] at bit 22

 *          byte 3[0:7] at bit 8

 *          byte 4[0:7] at bit 0

 *

 * To prevent 0 cycles, 1's are inject at bit 8 in lfrs17 and bit 21 in

 * lfsr25.

 *

 */

int

acss(ACSS_KEY *key, unsigned long len, const unsigned char *in,

    unsigned char *out)

{

	unsigned long i;

	unsigned long lfsr17tmp, lfsr25tmp, lfsrsumtmp;

	lfsrsumtmp = lfsr17tmp = lfsr25tmp = 0;

	/* keystream is sum of lfsrs */

	for (i = 0; i < len; i++) {

		lfsr17tmp = key->lfsr17 ^ (key->lfsr17 >> 14);

		key->lfsr17 = (key->lfsr17 >> 8)

			^ (lfsr17tmp << 9)

			^ (lfsr17tmp << 12)

			^ (lfsr17tmp << 15);

		key->lfsr17 &= 0x1ffff;	/* 17 bit LFSR */

		lfsr25tmp = key->lfsr25

			^ (key->lfsr25 >> 3)

			^ (key->lfsr25 >> 4)

			^ (key->lfsr25 >> 12);

		key->lfsr25 = (key->lfsr25 >> 8) ^ (lfsr25tmp << 17);

		key->lfsr25 &= 0x1ffffff;	/* 25 bit LFSR */

		lfsrsumtmp = key->lfsrsum;

		/* addition */

		switch (key->mode) {

		case ACSS_AUTHENTICATE:

		case ACSS_DATA:

			key->lfsrsum = 0xff & ~(key->lfsr17 >> 9);

			key->lfsrsum += key->lfsr25 >> 17;

			break;

		case ACSS_SESSIONKEY:

			key->lfsrsum = key->lfsr17 >> 9;

			key->lfsrsum += key->lfsr25 >> 17;

			break;

		case ACSS_TITLEKEY:

			key->lfsrsum = key->lfsr17 >> 9;

			key->lfsrsum += 0xff & ~(key->lfsr25 >> 17);

			break;

		default:

			return 1;

		}

		key->lfsrsum += (lfsrsumtmp >> 8);

		if (key->encrypt) {

			out[i] = sboxenc[(in[i] ^ key->lfsrsum) & 0xff];

		} else {

			out[i] = (sboxdec[in[i]] ^ key->lfsrsum) & 0xff;

		}

	}

	return 0;

}

static void

acss_seed(ACSS_KEY *key)

{

	int i;

	/* if available, mangle with subkey */

	if (key->subkey_avilable) {

		for (i = 0; i < ACSS_KEYSIZE; i++)

			key->seed[i] = reverse[key->data[i] ^ key->subkey[i]];

	} else {

		for (i = 0; i < ACSS_KEYSIZE; i++)

			key->seed[i] = reverse[key->data[i]];

	}

	/* seed lfsrs */

	key->lfsr17 = key->seed[1]

		| (key->seed[0] << 9)

		| (1 << 8);	/* inject 1 at bit 9 */

	key->lfsr25 = key->seed[4]

		| (key->seed[3] << 8)

		| ((key->seed[2] & 0x1f) << 16)

		| ((key->seed[2] & 0xe0) << 17)

			| (1 << 21);	/* inject 1 at bit 22 */

	key->lfsrsum = 0;

}

void

acss_setkey(ACSS_KEY *key, const unsigned char *data, int enc, int mode)

{

	memcpy(key->data, data, sizeof(key->data));

	memset(key->subkey, 0, sizeof(key->subkey));

	if (enc != -1)

		key->encrypt = enc;

	key->mode = mode;

	key->subkey_avilable = 0;

	acss_seed(key);

}

void

acss_setsubkey(ACSS_KEY *key, const unsigned char *subkey)

{

	memcpy(key->subkey, subkey, sizeof(key->subkey));

	key->subkey_avilable = 1;

	acss_seed(key);

}

#endif