Subversion Repositories filter_foundry

/*

    This file is part of "Filter Foundry", a filter plugin for Adobe Photoshop

    Copyright (C) 2003-2009 Toby Thain, toby@telegraphics.com.au

    Copyright (C) 2018-2022 Daniel Marschall, ViaThinkSoft

    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, write to the Free Software

    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

*/

#include <stddef.h>

#include <stdint.h>

#include "ff.h"

// Random seed for obfuscation "17 05 83 52 2a 97 16 74"

// During the standalone-make process, this value will be changed by manipulating the 8BF file.

// Therefore, the 32/64 bit 8BF files *MUST* contain the key contiguous and preferrpreferablyibly 4-aligned

// Why do I use GetObfuscSeed?

// 1. Because I prefer the key in side code segment so that it is better hidden than if it was in a data segment.

// 2. Since the code segment is closer to the 8BF file start, the search+replace of the key is faster

// Please also note:

// The 8BF file *MUST* only contain the seed A SINGLE TIME

// (In the Non-Standalone filter actually 3 times, because we have 2 resourced containing the 32/64 template DLLs)

#if defined(__WATCOMC__)

        uint64_t GetObfuscSeed() {

                // Due to "volatile", this value will only exist a single time in the binary file.

                // This char array will result in contiguous chars in OpenWatcom.

                // In MSVC++, the array will be built using several "mov ..." OP codes.

                volatile char seed[8] = { '\x17', '\x05', '\x83', '\x52', '\x2a', '\x97', '\x16', '\x74' };

                return (uint64_t)seed;

        }

#elif defined(_MSC_VER)

        #ifdef _WIN64

        // Note: For MSVCC 64-bit, neither making the method volatile, nor including a volatile variable did avoid inlining.

        // so we use __declspec(noinline)

        __declspec(noinline) uint64_t GetObfuscSeed() {

                // TODO: Not 4-byte aligned! (both variants)

                //volatile uint64_t seed = 0x7416972a52830517ull;

                //return seed;

                return 0x7416972a52830517ull;

        }

        #else

        __declspec(noinline) uint64_t GetObfuscSeed() {

                //volatile int test = 0;

                uint64_t* addr = NULL;

                __asm {

                        mov eax, seed // Doesn't work in OpenWatcom

                        mov addr, eax

                        jmp end

                        align 4 // Doesn't work in OpenWatcom

                        seed:

                                _emit 0x17 // Doesn't work in OpenWatcom

                                _emit 0x05

                                _emit 0x83

                                _emit 0x52

                                _emit 0x2A

                                _emit 0x97

                                _emit 0x16

                                _emit 0x74

                                /*

                                pop ss

                                add eax, 0x972a5283

                                push ss

                                jz seed

                                */

                        end:

                }

                return addr == NULL ? 0 : *addr;

        }

        #endif

#else

        // Unfortunately, with this compiler, we the value needs to be in the .data segment...

        // Due to "const volatile", this value will only exist a single time in the binary file.

        const volatile uint64_t seed = 0x7416972a52830517ull;

        uint64_t GetObfuscSeed() {

                return seed;

        }

#endif

int rand_msvcc(unsigned int* seed) {

        *seed = *seed * 214013L + 2531011L;

        return (*seed >> 16) & 0x7fff; /* Scale between 0 and RAND_MAX */

}

int rand_openwatcom(unsigned int* seed) {

        // https://github.com/open-watcom/open-watcom-v2/blob/master/bld/clib/math/c/rand.c

        *seed = *seed * 1103515245L + 12345L;

        return (*seed >> 16) & 0x7fff; /* Scale between 0 and RAND_MAX */

}

void xorshift(unsigned char** p, uint32_t* x32, size_t num) {

        size_t i;

        unsigned char* x = *p;

        for (i = 0; i < num; i++) {

                // https://de.wikipedia.org/wiki/Xorshift

                *x32 ^= *x32 << 13;

                *x32 ^= *x32 >> 17;

                *x32 ^= *x32 << 5;

                *x++ ^= *x32;

        }

        *p = x;

}

#ifndef CHAR_BIT

#define CHAR_BIT 8

#endif

uint64_t rol_u64(uint64_t value, uint64_t by) {

        return value << by | value >> (sizeof(uint64_t) * CHAR_BIT - by);

}

void rolshift(unsigned char** p, uint64_t* x64, size_t num) {

        size_t i;

        unsigned char* x = *p;

        for (i = 0; i < num; i++) {

                *x++ ^= *x64;

                *x64 = rol_u64(*x64, 1);

        }

        *p = x;

}

uint32_t crc32b(char *data, int nLength) {

        int i, j, k;

        uint32_t crc, mask;

        char byte;

        i = 0;

        crc = 0xFFFFFFFF;

        for(k=0;k<nLength;k++) {

                byte = data[k];

                crc = crc ^ byte;

                for (j = 7; j >= 0; j--) {

                        mask = (-1) * (crc & 1);

                        crc = (crc >> 1) ^ (0xEDB88320 & mask);

                }

                i++;

        }

        return ~crc;

}

static const uint64_t crc64_tab[256] = {

        0x0000000000000000ULL, 0x42F0E1EBA9EA3693ULL, 0x85E1C3D753D46D26ULL,

        0xC711223CFA3E5BB5ULL, 0x493366450E42ECDFULL, 0x0BC387AEA7A8DA4CULL,

        0xCCD2A5925D9681F9ULL, 0x8E224479F47CB76AULL, 0x9266CC8A1C85D9BEULL,

        0xD0962D61B56FEF2DULL, 0x17870F5D4F51B498ULL, 0x5577EEB6E6BB820BULL,

        0xDB55AACF12C73561ULL, 0x99A54B24BB2D03F2ULL, 0x5EB4691841135847ULL,

        0x1C4488F3E8F96ED4ULL, 0x663D78FF90E185EFULL, 0x24CD9914390BB37CULL,

        0xE3DCBB28C335E8C9ULL, 0xA12C5AC36ADFDE5AULL, 0x2F0E1EBA9EA36930ULL,

        0x6DFEFF5137495FA3ULL, 0xAAEFDD6DCD770416ULL, 0xE81F3C86649D3285ULL,

        0xF45BB4758C645C51ULL, 0xB6AB559E258E6AC2ULL, 0x71BA77A2DFB03177ULL,

        0x334A9649765A07E4ULL, 0xBD68D2308226B08EULL, 0xFF9833DB2BCC861DULL,

        0x388911E7D1F2DDA8ULL, 0x7A79F00C7818EB3BULL, 0xCC7AF1FF21C30BDEULL,

        0x8E8A101488293D4DULL, 0x499B3228721766F8ULL, 0x0B6BD3C3DBFD506BULL,

        0x854997BA2F81E701ULL, 0xC7B97651866BD192ULL, 0x00A8546D7C558A27ULL,

        0x4258B586D5BFBCB4ULL, 0x5E1C3D753D46D260ULL, 0x1CECDC9E94ACE4F3ULL,

        0xDBFDFEA26E92BF46ULL, 0x990D1F49C77889D5ULL, 0x172F5B3033043EBFULL,

        0x55DFBADB9AEE082CULL, 0x92CE98E760D05399ULL, 0xD03E790CC93A650AULL,

        0xAA478900B1228E31ULL, 0xE8B768EB18C8B8A2ULL, 0x2FA64AD7E2F6E317ULL,

        0x6D56AB3C4B1CD584ULL, 0xE374EF45BF6062EEULL, 0xA1840EAE168A547DULL,

        0x66952C92ECB40FC8ULL, 0x2465CD79455E395BULL, 0x3821458AADA7578FULL,

        0x7AD1A461044D611CULL, 0xBDC0865DFE733AA9ULL, 0xFF3067B657990C3AULL,

        0x711223CFA3E5BB50ULL, 0x33E2C2240A0F8DC3ULL, 0xF4F3E018F031D676ULL,

        0xB60301F359DBE0E5ULL, 0xDA050215EA6C212FULL, 0x98F5E3FE438617BCULL,

        0x5FE4C1C2B9B84C09ULL, 0x1D14202910527A9AULL, 0x93366450E42ECDF0ULL,

        0xD1C685BB4DC4FB63ULL, 0x16D7A787B7FAA0D6ULL, 0x5427466C1E109645ULL,

        0x4863CE9FF6E9F891ULL, 0x0A932F745F03CE02ULL, 0xCD820D48A53D95B7ULL,

        0x8F72ECA30CD7A324ULL, 0x0150A8DAF8AB144EULL, 0x43A04931514122DDULL,

        0x84B16B0DAB7F7968ULL, 0xC6418AE602954FFBULL, 0xBC387AEA7A8DA4C0ULL,

        0xFEC89B01D3679253ULL, 0x39D9B93D2959C9E6ULL, 0x7B2958D680B3FF75ULL,

        0xF50B1CAF74CF481FULL, 0xB7FBFD44DD257E8CULL, 0x70EADF78271B2539ULL,

        0x321A3E938EF113AAULL, 0x2E5EB66066087D7EULL, 0x6CAE578BCFE24BEDULL,

        0xABBF75B735DC1058ULL, 0xE94F945C9C3626CBULL, 0x676DD025684A91A1ULL,

        0x259D31CEC1A0A732ULL, 0xE28C13F23B9EFC87ULL, 0xA07CF2199274CA14ULL,

        0x167FF3EACBAF2AF1ULL, 0x548F120162451C62ULL, 0x939E303D987B47D7ULL,

        0xD16ED1D631917144ULL, 0x5F4C95AFC5EDC62EULL, 0x1DBC74446C07F0BDULL,

        0xDAAD56789639AB08ULL, 0x985DB7933FD39D9BULL, 0x84193F60D72AF34FULL,

        0xC6E9DE8B7EC0C5DCULL, 0x01F8FCB784FE9E69ULL, 0x43081D5C2D14A8FAULL,

        0xCD2A5925D9681F90ULL, 0x8FDAB8CE70822903ULL, 0x48CB9AF28ABC72B6ULL,

        0x0A3B7B1923564425ULL, 0x70428B155B4EAF1EULL, 0x32B26AFEF2A4998DULL,

        0xF5A348C2089AC238ULL, 0xB753A929A170F4ABULL, 0x3971ED50550C43C1ULL,

        0x7B810CBBFCE67552ULL, 0xBC902E8706D82EE7ULL, 0xFE60CF6CAF321874ULL,

        0xE224479F47CB76A0ULL, 0xA0D4A674EE214033ULL, 0x67C58448141F1B86ULL,

        0x253565A3BDF52D15ULL, 0xAB1721DA49899A7FULL, 0xE9E7C031E063ACECULL,

        0x2EF6E20D1A5DF759ULL, 0x6C0603E6B3B7C1CAULL, 0xF6FAE5C07D3274CDULL,

        0xB40A042BD4D8425EULL, 0x731B26172EE619EBULL, 0x31EBC7FC870C2F78ULL,

        0xBFC9838573709812ULL, 0xFD39626EDA9AAE81ULL, 0x3A28405220A4F534ULL,

        0x78D8A1B9894EC3A7ULL, 0x649C294A61B7AD73ULL, 0x266CC8A1C85D9BE0ULL,

        0xE17DEA9D3263C055ULL, 0xA38D0B769B89F6C6ULL, 0x2DAF4F0F6FF541ACULL,

        0x6F5FAEE4C61F773FULL, 0xA84E8CD83C212C8AULL, 0xEABE6D3395CB1A19ULL,

        0x90C79D3FEDD3F122ULL, 0xD2377CD44439C7B1ULL, 0x15265EE8BE079C04ULL,

        0x57D6BF0317EDAA97ULL, 0xD9F4FB7AE3911DFDULL, 0x9B041A914A7B2B6EULL,

        0x5C1538ADB04570DBULL, 0x1EE5D94619AF4648ULL, 0x02A151B5F156289CULL,

        0x4051B05E58BC1E0FULL, 0x87409262A28245BAULL, 0xC5B073890B687329ULL,

        0x4B9237F0FF14C443ULL, 0x0962D61B56FEF2D0ULL, 0xCE73F427ACC0A965ULL,

        0x8C8315CC052A9FF6ULL, 0x3A80143F5CF17F13ULL, 0x7870F5D4F51B4980ULL,

        0xBF61D7E80F251235ULL, 0xFD913603A6CF24A6ULL, 0x73B3727A52B393CCULL,

        0x31439391FB59A55FULL, 0xF652B1AD0167FEEAULL, 0xB4A25046A88DC879ULL,

        0xA8E6D8B54074A6ADULL, 0xEA16395EE99E903EULL, 0x2D071B6213A0CB8BULL,

        0x6FF7FA89BA4AFD18ULL, 0xE1D5BEF04E364A72ULL, 0xA3255F1BE7DC7CE1ULL,

        0x64347D271DE22754ULL, 0x26C49CCCB40811C7ULL, 0x5CBD6CC0CC10FAFCULL,

        0x1E4D8D2B65FACC6FULL, 0xD95CAF179FC497DAULL, 0x9BAC4EFC362EA149ULL,

        0x158E0A85C2521623ULL, 0x577EEB6E6BB820B0ULL, 0x906FC95291867B05ULL,

        0xD29F28B9386C4D96ULL, 0xCEDBA04AD0952342ULL, 0x8C2B41A1797F15D1ULL,

        0x4B3A639D83414E64ULL, 0x09CA82762AAB78F7ULL, 0x87E8C60FDED7CF9DULL,

        0xC51827E4773DF90EULL, 0x020905D88D03A2BBULL, 0x40F9E43324E99428ULL,

        0x2CFFE7D5975E55E2ULL, 0x6E0F063E3EB46371ULL, 0xA91E2402C48A38C4ULL,

        0xEBEEC5E96D600E57ULL, 0x65CC8190991CB93DULL, 0x273C607B30F68FAEULL,

        0xE02D4247CAC8D41BULL, 0xA2DDA3AC6322E288ULL, 0xBE992B5F8BDB8C5CULL,

        0xFC69CAB42231BACFULL, 0x3B78E888D80FE17AULL, 0x7988096371E5D7E9ULL,

        0xF7AA4D1A85996083ULL, 0xB55AACF12C735610ULL, 0x724B8ECDD64D0DA5ULL,

        0x30BB6F267FA73B36ULL, 0x4AC29F2A07BFD00DULL, 0x08327EC1AE55E69EULL,

        0xCF235CFD546BBD2BULL, 0x8DD3BD16FD818BB8ULL, 0x03F1F96F09FD3CD2ULL,

        0x41011884A0170A41ULL, 0x86103AB85A2951F4ULL, 0xC4E0DB53F3C36767ULL,

        0xD8A453A01B3A09B3ULL, 0x9A54B24BB2D03F20ULL, 0x5D45907748EE6495ULL,

        0x1FB5719CE1045206ULL, 0x919735E51578E56CULL, 0xD367D40EBC92D3FFULL,

        0x1476F63246AC884AULL, 0x568617D9EF46BED9ULL, 0xE085162AB69D5E3CULL,

        0xA275F7C11F7768AFULL, 0x6564D5FDE549331AULL, 0x279434164CA30589ULL,

        0xA9B6706FB8DFB2E3ULL, 0xEB46918411358470ULL, 0x2C57B3B8EB0BDFC5ULL,

        0x6EA7525342E1E956ULL, 0x72E3DAA0AA188782ULL, 0x30133B4B03F2B111ULL,

        0xF7021977F9CCEAA4ULL, 0xB5F2F89C5026DC37ULL, 0x3BD0BCE5A45A6B5DULL,

        0x79205D0E0DB05DCEULL, 0xBE317F32F78E067BULL, 0xFCC19ED95E6430E8ULL,

        0x86B86ED5267CDBD3ULL, 0xC4488F3E8F96ED40ULL, 0x0359AD0275A8B6F5ULL,

        0x41A94CE9DC428066ULL, 0xCF8B0890283E370CULL, 0x8D7BE97B81D4019FULL,

        0x4A6ACB477BEA5A2AULL, 0x089A2AACD2006CB9ULL, 0x14DEA25F3AF9026DULL,

        0x562E43B4931334FEULL, 0x913F6188692D6F4BULL, 0xD3CF8063C0C759D8ULL,

        0x5DEDC41A34BBEEB2ULL, 0x1F1D25F19D51D821ULL, 0xD80C07CD676F8394ULL,

        0x9AFCE626CE85B507ULL

};

/*

 * ECMA 182 CRC64, taken from https://searchcode.com/file/68313281/lib/crc64.c/

 */

uint64_t crc64(const unsigned char* data, size_t len)

{

        uint64_t crc = 0;

        while (len--) {

                int i = ((int)(crc >> 56) ^ *data++) & 0xFF;

                crc = crc64_tab[i] ^ (crc << 8);

        }

        return crc;

}

int obfuscation_version(PARM_T* pparm) {

        uint32_t obfusc_info = pparm->unknown2;

        if (obfusc_info == 0x00000000) { // 00 00 00 00

                // Photoshop FilterFactory default initialization of field "unknown2"

                // (no obfuscation)

                return 0;

        }

        else if (obfusc_info == 0x00000001) { // 01 00 00 00

                // Premiere FilterFactory default initialization of field "unknown1" (it is at the offset of Photoshop's "unknown2")

                // (no obfuscation)

                return 0;

        }

        else if (obfusc_info == 0x90E364A3) { // A3 64 E3 90

                // Version 1 obfuscation (Filter Foundry 1.4b8,9,10)

                return 1;

        }

        else if (obfusc_info == 0xE2CFCA34) { // 34 CA CF E2

                // Version 2 obfuscation (Filter Foundry 1.7b1)

                return 2;

        }

        else if ((obfusc_info >= 4) && (obfusc_info <= 0xFF)) { // xx 00 00 00

                // Version 4 obfuscation (Filter Foundry 1.7.0.7)

                // Version 5 obfuscation (Filter Foundry 1.7.0.8)

                // Version 6 obfuscation (Filter Foundry 1.7.0.10)

                // Future: Version 7, 8, ... 255

                return obfusc_info;

        }

        else {

                // Version 3 obfuscation (Filter Foundry 1.7.0.5)

                // obfusc_info is the srand() seed and is equal to the time(0) build timestamp

                return 3;

        }

}

uint64_t obfusc(PARM_T* pparm) {

        // Version 6 obfuscation (Introduced in Filter Foundry 1.7.0.10)

        unsigned char* p;

        uint64_t initial_seed, rolseed;

        uint32_t xorseed;

        pparm->unknown1 = 0;

        pparm->unknown2 = 0;

        pparm->unknown3 = 0;

#ifdef MAC_ENV

        // Currently, make_mac.c does not implement modifying the executable code (TODO),

        // so we will use the default initial_seed!

        initial_seed = GetObfuscSeed();

#else

        // Give always the same seed if the parameters are the same. No random values.

        // This initial seed will be returned and built into the executable code by make_win.c

        initial_seed = crc64((unsigned char*)pparm, sizeof(PARM_T));

#endif

        // AFTER unknown1-3 have been set to 0, calculate the checksum!

        pparm->unknown1 = crc32b((char*)pparm, sizeof(PARM_T));

        xorseed = initial_seed & 0xFFFFFFFF;

        p = (unsigned char*)pparm;

        xorshift(&p, &xorseed, sizeof(PARM_T));

        rolseed = initial_seed;

        p = (unsigned char*)pparm;

        rolshift(&p, &rolseed, sizeof(PARM_T));

        pparm->unknown2 = 6; // obfusc version

        return initial_seed;

}

void deobfusc(PARM_T* pparm) {

        uint32_t obfusc_version;

        size_t size = sizeof(PARM_T);

        obfusc_version = obfuscation_version(pparm);

        switch (obfusc_version) {

                case 0:

                        // no obfuscation

                        return;

                case 1: {

                        // Version 1 obfuscation (Filter Foundry 1.4b8,9,10)

                        // Filter built with VC++ (official release by Toby Thain)

                        unsigned char* p;

                        size_t i;

                        uint32_t seed;

                        seed = 0xdc43df3c;

                        for (i = size, p = (unsigned char*)pparm; i--;) {

                                *p++ ^= rand_msvcc(&seed);

                        }

                        break;

                }

                case 2: {

                        // Version 2 obfuscation (Filter Foundry 1.7b1)

                        // Compiler independent

                        unsigned char* p;

                        size_t i;

                        uint32_t seed;

                        seed = 0x95d4a68f;

                        for (i = size, p = (unsigned char*)pparm; i--;) {

                                seed ^= seed << 13;

                                seed ^= seed >> 17;

                                seed ^= seed << 5;

                                *p++ ^= seed;

                        }

                        break;

                }

                case 3: {

                        // Version 3 obfuscation (Filter Foundry 1.7.0.5)

                        // NO loading of other implementation supported, but that doesn't matter since

                        // obfuscation and protection is combined in Filter Factory >= 1.7.0.5.

                        // Using rand() is more secure, because it differs from compiler to compiler, so

                        // it is harder to read a protected 8BF plugin.

                        // Note that rand() in combination with srand() is deterministic, so it is safe

                        // to use it: https://stackoverflow.com/questions/55438293/does-rand-function-in-c-follows-non-determinstc-algorithm

                        // Note: 32-Bit FF is built using OpenWatcom (to support Win95), while 64-Bit FF is built using Microsoft Visual C++

                        unsigned char* p;

                        size_t i;

                        uint32_t seed;

                        size_t seed_position;

                        seed = pparm->unknown2;

                        seed_position = offsetof(PARM_T, unknown2); // = offsetof(PARM_T_PREMIERE, unknown1)

                        srand(seed);

                        p = (unsigned char*)pparm;

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

                                *p++ ^= (int)(rand() * 1.0 / ((double)RAND_MAX + 1) * 256);

                        }

                        *((uint32_t*)p) = 0; // here was the seed. Fill it with 0x00000000

                        p += 4;

                        for (i = 0; i < size - seed_position - 4; i++) {

                                *p++ ^= (int)(rand() * 1.0 / ((double)RAND_MAX + 1) * 256);

                        }

                        break;

                }

                case 4:

                case 5: {

                        // Version 4 obfuscation (Filter Foundry 1.7.0.7)

                        // Version 5 obfuscation (Filter Foundry 1.7.0.8)

                        // Not compiler dependent, but individual for each standalone filter

                        // It is important that this code works for both x86 and x64 indepdently from the used compiler,

                        // otherwise, the cross-make x86/x64 won't work!

                        // Version 5 contains a seed requirement (checksum).

                        unsigned char* p;

                        size_t seed_position;

                        uint32_t seed, initial_seed;

                        initial_seed = GetObfuscSeed() & 0xFFFFFFFF; // this value will be manipulated during the building of each individual filter (see make_win.c)

                        seed = initial_seed;

                        seed_position = offsetof(PARM_T, unknown2); // = offsetof(PARM_T_PREMIERE, unknown1)

                        if (obfusc_version == 5) {

                                // make v4 and v5 intentionally incompatible to avoid a downgrade-attack

                                seed ^= 0xFFFFFFFF;

                        }

                        p = (unsigned char*)pparm;

                        xorshift(&p, &seed, seed_position);

                        *((uint32_t*)p) = 0; // here was the version info. Fill it with 0x00000000

                        p += 4; // obfusc info was 4 or 5

                        xorshift(&p, &seed, size - seed_position - 4);

                        if (obfusc_version == 5) {

                                pparm->unknown2 = 0; // make sure crc32b matches always

                                if (crc32b((char*)pparm, sizeof(PARM_T)) != initial_seed) {

                                        // Integrity check failed!

                                        memset(pparm, 0, sizeof(PARM_T)); // invalidate everything

                                }

                        }

                        break;

                }

                case 6: {

                        // Version 6 obfuscation (Filter Foundry 1.7.0.10)

                        // Not compiler dependent, but individual for each standalone filter

                        // It is important that this code works for both x86 and x64 indepdently from the used compiler,

                        // otherwise, the cross-make x86/x64 won't work!

                        unsigned char* p;

                        uint32_t xorseed, checksum;

                        uint64_t initial_seed, rolseed;

                        initial_seed = GetObfuscSeed(); // this value will be manipulated during the building of each individual filter (see make_win.c)

                        rolseed = initial_seed;

                        p = (unsigned char*)pparm;

                        rolshift(&p, &rolseed, sizeof(PARM_T));

                        xorseed = initial_seed & 0xFFFFFFFF;

                        p = (unsigned char*)pparm;

                        xorshift(&p, &xorseed, sizeof(PARM_T));

                        checksum = pparm->unknown1;

                        pparm->unknown1 = 0;

                        pparm->unknown2 = 0;

                        pparm->unknown3 = 0;

                        if (checksum != crc32b((char*)pparm, sizeof(PARM_T))) {

                                // Integrity check failed!

                                memset(pparm, 0, sizeof(PARM_T)); // invalidate everything

                        }

                        break;

                }

                default: {

                        // Obfuscation version unexpected!

                        memset(pparm, 0, sizeof(PARM_T)); // invalidate everything

                        // If "return" is present: Calling function will receive an invalid cbSize value, hence showing "incompatible obfuscation"

                        // If "return" is not present: Then the code below will set a correct cbSize and iProtect flag if obfusc_version>=3, which will raise the error "filter is protected"

                        return;

                }

        }

        if ((pparm->cbSize != PARM_SIZE) &&

                (pparm->cbSize != PARM_SIZE_PREMIERE) &&

                (pparm->cbSize != PARM_SIG_MAC)) {

                memset(pparm, 0, sizeof(PARM_T)); // invalidate everything

        }

        if (obfusc_version >= 3) {

                // Filter Foundry >= 1.7.0.5 combines obfuscation and protection

                // when a standalone filter is built. Theoretically, you can un-protect a

                // plugin, even if it is obfuscated, just by bit-flipping the LSB of byte 0x164.

                // Therefore, we enforce that the plugin is protected!

                pparm->iProtected = 1;

                // Furthermore, if obfuscation 3+ failed (since the seed is individual for each 8BF file),

                // we still want that load_*.c is able to detect pparm->iProtected instead

                // of throwing the error "Incompatible obfuscation".

                pparm->cbSize = PARM_SIZE;

                pparm->standalone = 1;

        }

        if (obfusc_version >= 1) {

                // information was lost due to obfuscation. Make sure it is zero.

                pparm->unknown2 = 0;

        }

        if (obfusc_version >= 6) {

                // information was lost due to checksum. Make sure it is zero.

                pparm->unknown1 = 0;

        }

}