mtvhd-xor.c

/* DVB USB framework compliant Linux driver for the SKNET MonsterTV HD ISDB-T
 * receiver. (Local decryption: XOR)
 *
 * Copyright (c) 2009 Gombei Nanashi
 *
 * 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.  If not, see <http://www.gnu.org/licenses/>.
 */
#include "mtvhd.h"

/* Fixed xor-key for ASIE5606 */
static uint8_t mtvhd_xor_key[] = {
	0x6D, 0x4E, 0xF0, 0x1E, 0x59, 0x8B, 0xB2, 0xF0,
	0x31, 0xF9, 0xD0, 0x85, 0xDD, 0x84, 0x4A, 0x6C,
	0x15, 0x1C, 0x1C, 0x0A, 0x5B, 0x61, 0x6F, 0x1A,
	0xAD, 0x60, 0x46, 0xF2, 0xD5, 0x03, 0x91, 0xC7,
	0xB7, 0xDE, 0x68, 0x9A, 0x07, 0x47, 0x62, 0x5E,
	0x39, 0xD6, 0x7E, 0x45, 0x10, 0x9D, 0x1A, 0xC4,
	0x4C, 0x7F, 0xB7, 0x03, 0xCC, 0xAD, 0x72, 0x6C,
	0xE9, 0x1B, 0x85, 0xA8, 0xEE, 0x4B, 0xA9, 0x3A,
	0xFF, 0xF1, 0x3B, 0x16, 0xE0, 0x59, 0x4C, 0x3A,
	0xD5, 0x4A, 0x14, 0x95, 0x0A, 0xD4, 0x25, 0x23,
	0xF6, 0x2F, 0xE3, 0x57, 0x35, 0xCE, 0x52, 0x84,
	0x11, 0xA3, 0xCB, 0x34, 0xA7, 0x15, 0x60, 0xE1,
	0x98, 0x71, 0xF4, 0x1F, 0xF7, 0xBD, 0x22, 0x4B,
	0x61, 0x8A, 0xD6, 0xAF, 0x24, 0x27, 0xC3, 0xA7,
	0x07, 0x9B, 0xA5, 0x57, 0x83, 0x80, 0x58, 0x07,
	0x1D, 0xDE, 0x0A, 0xD8, 0xB9, 0x0A, 0xBE, 0xAC,
	0xA9, 0x76, 0x00, 0x1C, 0x23, 0x9F, 0x82, 0x79,
	0x41, 0x56, 0xC8, 0x83, 0xC3, 0x38, 0x37, 0x4B,
	0x5A, 0xED, 0xC9, 0xD5, 0xF2, 0x87, 0x02, 0xC3,
	0x79, 0xA0, 0x61, 0xD9, 0x63, 0x50, 0xCA, 0x72,
	0xC2, 0x51, 0x40, 0x98, 0xD9, 0x8B, 0xED, 0xA9,
	0xA1, 0x4C, 0xA5, 0xE7, 0xAF, 0xF2, 0x08, 0x4D,
	0x82, 0xF8, 0xD5, 0x02, 0x61, 0xD8, 0xC2, 0xE1
};

/* Decrypt TS packet with fixed XOR pattern */
void mtvhd_xor_decrypt(void *crypto_ctx, u8 *data)
{
	int i;

	/* Skip first 4 byte header */
	for (i = 4; i < TS_SIZE; i++) {
		data[i] ^= mtvhd_xor_key[i - 4];
	}

	return;
}