diff options
Diffstat (limited to 'src/mame/igs/igs036crypt.cpp')
-rw-r--r-- | src/mame/igs/igs036crypt.cpp | 309 |
1 files changed, 309 insertions, 0 deletions
diff --git a/src/mame/igs/igs036crypt.cpp b/src/mame/igs/igs036crypt.cpp new file mode 100644 index 00000000000..7fb3bed9e7d --- /dev/null +++ b/src/mame/igs/igs036crypt.cpp @@ -0,0 +1,309 @@ +// license:BSD-3-Clause +// copyright-holders:Andreas Naive,David Haywood +#include "emu.h" +#include "igs036crypt.h" + +/**************************************************************************** +IGS036 encryption emulation + +The encryption used by the IGS036 seems to be another iteration over +previous IGS encryption schemes. Basically, it consists on a rotation-based +non-trivial obfuscation layered upon a simple address-based XOR encryption +(similar to the ones found in previous IGS circuits). + +The scheme works on 16-bits words and is probably designed to depend on 24 bits of +(word-) address; in what follows, we will refer to the 8 lowest ones simply as the +lowest bits of the address, and the other 16 as the highest bits the address. + +The address-based XOR can be thought as 16 one-bit XORs against key bits +controlled by certain combinations of up to three address bits. The game key is +comprised of 256 8-bits values provided by the internal ARM; every 8-bit value +in the key is used on those words whose address match the index modulus 256; +in a given key byte, every bit affects two positions of the corresponding 16-bits +encrypted words. +This use of the key is similar to the one found in previous instantiations of +IGS circuits. + +What is new in the IGS036 is the use of an obfuscation working this way: + +1) The highest bits of the address are split in 4 groups, every of which controls +a rotation by a shift of (plus or minus) 9, 1, 2 and 4 respectively. +2) For every address, the highest bit of the group set in the address controls +the activation/deactivation of the rotation for his group, using an associated +(and fixed) boolean function depending on the lowest bits of the address. +3) If the group rotation is to be activated according to 2), then another +fixed group-level boolean functions (again, depending on the lowest bits of the +address) control the direction (left or right) of the rotation. +4) One of the groups (the associated with the shift by 9) interacts with the other +three by inverting (when active itself) the activation/deactivation patterns of +the other three. +5) The lowest bits of the address control a further rotation(independent +on the highest bits of the address). +6) Finally, a global bitswap is applied. + +All the associated boolean functions are clearly of low complexity, so it should +be expected that the hardware is calculating them that way rather than using +lookup tables or otherwise. It should be stressed that this obfuscation is done +system-wide without dependence on the game keys. + +On a different note, the unused tail of the ROMs are pattern-filled and, more interestingly, +that region appears to be hiding 20-bytes values (SHA-1 hashes?) located at +positions which vary per set. See the table below. + +driver 20-bytes value position in the ROM +--------- ---------------------------------- +orleg2o $763984-$763997 +orleg2 $76C77C-$76C78F +kov3 $718040-$718053 +kof98umh $E50E60-$E50E73 + +TO-DO: complete the table with the 20-bytes values + +*****************************************************************************/ + +igs036_decryptor::igs036_decryptor(const uint8_t* game_key) + : key(game_key) +{ +} + +void igs036_decryptor::decrypter_rom(uint16_t* rom, int size, int offset) +{ + for (int i = 0; i < size / 2; i++) + { + rom[i] = decrypt(rom[i], i+offset); + } +} + +uint16_t igs036_decryptor::decrypt(uint16_t cipherword, int word_address)const +{ + // key-independent manipulation + int aux = deobfuscate(cipherword, word_address); + + // key-dependent manipulation + for (int i=0; i<16; ++i) + { + if ((word_address&triggers[i][0]) == triggers[i][1]) + aux ^= BIT(key[word_address&0xff],i&7) << i; + else + aux ^= BIT(0x1a3a, i) << i; + } + + return aux; +} + +uint16_t igs036_decryptor::deobfuscate(uint16_t cipherword, int word_address)const +{ + // key-independent manipulation + int shift = rotation(word_address); + int aux = rol(cipherword, shift); + aux = bitswap<16>(aux, 10,9,8,7,0,15,6,5, 14,13,4,3,12,11,2,1); + + return aux; +} + +int igs036_decryptor::rotation(int address)const +{ + const int group15[] = {15,11, 7, 5}; // 15 is a guess + const int group14[] = {14, 9, 3, 2}; + const int group13[] = {13,10, 6, 1}; + const int group12[] = {12, 8, 4, 0}; + + // rotation depending on all the address bits + int enabled0 = rot_enabled(address, group15); + int rot = enabled0 * rot_group(address, group15) * 9; + + int enabled1 = enabled0 ^ rot_enabled(address, group14); + rot += enabled1 * rot_group(address, group14) * 1; + + int enabled2 = enabled0 ^ rot_enabled(address, group13); + rot += enabled2 * rot_group(address, group13) * 2; + + int enabled3 = enabled0 ^ rot_enabled(address, group12); + rot += enabled3 * rot_group(address, group12) * 4; + + // block-independent rotation (just depending on the lowest 8 bits) + int rot2 = 4*BIT(address,0); + rot2 += 1*BIT(address,4)*(BIT(address,0)*2-1); + rot2 += 4*BIT(address,3)*(BIT(address,0)*2-1); + rot2 *= (BIT(address,7)|(BIT(address,0)^BIT(address,1)^1))*2-1; + rot2 += 2*((BIT(address,0)^BIT(address,1))&(BIT(address,7)^1)); + + return (rot+rot2)&0xf; +} + +int igs036_decryptor::rot_enabled(int address, const int* group)const +{ + int enabled = 0; + for (int j=0; j<4; ++j) + { + if (BIT(address,8+group[j])) + { + int aux = address ^ (0x1b*BIT(address,2)); + enabled = rot_enabling[group[j]][aux&3](aux); + break; + } + } + + return enabled; +} + +int igs036_decryptor::rot_group(int address, const int* group)const +{ + int aux = rot_direction[group[0]&3][address&7](address); + return (aux*2)-1; +} + +uint16_t igs036_decryptor::rol(uint16_t num, int shift)const +{ + uint16_t r = num<<shift; + uint16_t l = num>>(16-shift); + + return r|l; +} + +// the triggers describe under what conditions are every one of the 16 XORs activated + +const uint32_t igs036_decryptor::triggers[16][2] = { + {0x000101, 0x000001}, {0x000802, 0x000800}, {0x000204, 0x000004}, {0x000408, 0x000408}, + {0x010010, 0x000010}, {0x020020, 0x000020}, {0x040040, 0x000040}, {0x080080, 0x080080}, + {0x100100, 0x000100}, {0x200200, 0x200000}, {0x400400, 0x400000}, {0x800801, 0x000001}, + {0x001004, 0x001000}, {0x002010, 0x002000}, {0x004040, 0x000040}, {0x008100, 0x008100} +}; + + +// The rotation depending on the 16 highest address bits depends on a series +// of function on the 8 lowest word-address bits. Some comments: +// * Bits #5 & #6 are unused so, in fact, they only depend on 6 address bits +// * The functions are clearly low-complexity boolean functions on those 6 bits +// rather than, say, random lookup tables +// * There are quite a number of functionally equivalent ways to implement +// those boolean functions, so the given implementation (by multiplexing +// over some simple functions) shouldn't be taken too seriously: while it's +// functionally correct, it doesn't necessarily represent the way the hardware +// is calculating them. + +static int unknown(int address) { return 0; } +static int cZero (int address) { return 0; } +static int cOne (int address) { return 1; } +static int bit_3 (int address) { return BIT(address,3); } +static int bit_4 (int address) { return BIT(address,4); } +static int bit_7 (int address) { return BIT(address,7); } +static int not_3 (int address) { return BIT(address,3)^1; } +static int not_4 (int address) { return BIT(address,4)^1; } +static int not_7 (int address) { return BIT(address,7)^1; } +static int xor_37 (int address) { return BIT(address,3)^BIT(address,7); } +static int xnor_37(int address) { return BIT(address,3)^BIT(address,7)^1; } +static int xor_47 (int address) { return BIT(address,4)^BIT(address,7); } +static int xnor_47(int address) { return BIT(address,4)^BIT(address,7)^1; } +static int nor_34 (int address) { return (BIT(address,3)|BIT(address,4))^1; } +static int impl_43(int address) { return BIT(address,3)||(BIT(address,4)^1); } + + +int (*igs036_decryptor::rot_enabling[16][4])(int) = { + {bit_3 , not_3 , bit_3 , not_3 }, + {bit_3 , not_3 , bit_3 , not_3 }, + {bit_4 , bit_4 , bit_4 , bit_4 }, + {bit_4 , not_4 , bit_4 , not_4 }, + {bit_3 , bit_3 , bit_3 , bit_3 }, + {nor_34 , bit_7 , bit_7 , cZero }, + {cZero , cOne , cZero , cOne }, + {impl_43, xor_37 , xnor_37, not_3 }, + {bit_3 , bit_3 , not_3 , not_3 }, + {bit_4 , bit_4 , not_4 , not_4 }, + {cZero , cZero , cZero , cZero }, + {nor_34 , bit_7 , not_7 , cOne }, + {bit_3 , not_3 , bit_3 , not_3 }, + {cZero , cOne , cOne , cZero }, + {bit_4 , not_4 , bit_4 , not_4 }, + {unknown, unknown, unknown, unknown}, +}; + +int (*igs036_decryptor::rot_direction[4][8])(int) = { + {bit_3 , xor_37 , xnor_37, not_3 , bit_3 , xor_37 , xnor_37, not_3 }, + {cZero , not_7 , not_7 , cZero , cZero , not_7 , not_7 , cZero }, + {bit_4 , xor_47 , xnor_47, not_4 , bit_4 , xor_47 , xnor_47, not_4 }, + {bit_3 , not_7 , bit_7 , cZero , cOne , not_7 , bit_7 , cZero }, +}; + +// ------------------------GAME KEYS--------------------------- + +// The keys below have been obtained by an automatic process +// exploiting the simple XOR scheme used by the system. Overall, the process, +// while simple, seems to be pretty robust, so few errors should be expected, +// if any. The exceptions are DDPDOJ & KOF98UMH (see below). + +const uint8_t m312cn_key[0x100] = { + 0x01, 0x09, 0x02, 0xab, 0x23, 0x20, 0xa2, 0x03, 0x10, 0x9b, 0xba, 0x33, 0x04, 0x2e, 0x27, 0x23, + 0x92, 0x11, 0x13, 0x93, 0x13, 0x86, 0x83, 0x02, 0x18, 0x8a, 0x8b, 0x9a, 0x10, 0x0f, 0x13, 0x83, + 0xa2, 0x98, 0x32, 0xba, 0x06, 0xab, 0x02, 0x0b, 0x1a, 0xa0, 0x13, 0x82, 0x84, 0x80, 0x8a, 0xa7, + 0x83, 0xb0, 0xb2, 0xab, 0x31, 0x07, 0xa3, 0x02, 0x10, 0x23, 0x8b, 0xb2, 0x2b, 0x0a, 0xa7, 0xa3, + 0x02, 0x7b, 0x12, 0xc3, 0x07, 0x0c, 0x43, 0xa6, 0x91, 0x91, 0x9b, 0xaa, 0x82, 0xca, 0x2e, 0x6a, + 0x43, 0x51, 0x02, 0xcb, 0x52, 0x8b, 0x56, 0x57, 0x88, 0xc3, 0x83, 0x1a, 0x8d, 0x51, 0x86, 0x0a, + 0xc1, 0x1b, 0x22, 0x5a, 0x07, 0x84, 0xa3, 0xce, 0xba, 0xfa, 0xab, 0x6a, 0xea, 0x2c, 0x2e, 0x67, + 0x00, 0x33, 0x53, 0xd3, 0x47, 0x98, 0x93, 0x62, 0x2b, 0x9b, 0x2b, 0x82, 0xed, 0x4b, 0x1a, 0x86, + 0xa0, 0xb9, 0x82, 0x0b, 0x27, 0x09, 0xa2, 0xab, 0x20, 0x3a, 0x8b, 0x0a, 0x84, 0x8d, 0x0b, 0x8f, + 0x83, 0x8a, 0x92, 0x13, 0x10, 0x18, 0x06, 0x96, 0x83, 0x89, 0x8b, 0x92, 0x1c, 0x92, 0x9b, 0x17, + 0x02, 0x2b, 0x02, 0x02, 0x06, 0x25, 0xa2, 0xab, 0xa8, 0x12, 0x13, 0x9a, 0x21, 0x27, 0x03, 0x2a, + 0xa3, 0x92, 0x33, 0xb2, 0x94, 0x12, 0x32, 0x9b, 0x90, 0xa0, 0x8a, 0x2a, 0x9a, 0xbb, 0xae, 0x1e, + 0x41, 0x2b, 0x92, 0xb2, 0x44, 0xe0, 0x02, 0x6f, 0x61, 0x30, 0x4a, 0x13, 0x61, 0x4f, 0x2e, 0xa6, + 0x52, 0x00, 0xc2, 0x8b, 0x53, 0x8f, 0x93, 0x4f, 0x5b, 0x01, 0x1a, 0x9b, 0xc6, 0x01, 0x03, 0x0b, + 0x42, 0x09, 0xf2, 0x62, 0x82, 0x41, 0x22, 0xc6, 0x90, 0x2a, 0xfa, 0x0b, 0x6c, 0xa0, 0x4f, 0x03, + 0xa0, 0x53, 0xf2, 0xbb, 0x46, 0x96, 0x23, 0x22, 0xd8, 0xfa, 0x12, 0xab, 0x88, 0x1a, 0x7a, 0x8a, +}; + +const uint8_t cjddzsp_key[0x100] = { + 0x11, 0x21, 0xa2, 0x1a, 0x84, 0xaf, 0x26, 0x0b, 0x3b, 0xbb, 0x12, 0x9b, 0x89, 0x80, 0x2f, 0x0a, + 0x91, 0x80, 0x93, 0x93, 0x80, 0x0b, 0x13, 0x93, 0x0a, 0x82, 0x8a, 0x12, 0x13, 0x05, 0x96, 0x17, + 0x81, 0xb1, 0xb3, 0xab, 0x06, 0x2a, 0x87, 0x83, 0x33, 0x93, 0x13, 0x8a, 0x28, 0xa8, 0x07, 0x8b, + 0x11, 0xa3, 0xb2, 0xa2, 0x23, 0x17, 0x17, 0xb6, 0x33, 0xa9, 0xa3, 0x23, 0xa0, 0xa3, 0x9b, 0xbb, + 0x70, 0xe8, 0x83, 0x72, 0xe6, 0xa2, 0xa2, 0x27, 0xbb, 0xc8, 0xf3, 0x42, 0x6d, 0xc8, 0x66, 0x47, + 0x93, 0x18, 0x12, 0x12, 0x13, 0x58, 0xd2, 0xc6, 0x49, 0x09, 0xc3, 0x0a, 0x81, 0x0b, 0xc2, 0xda, + 0xd2, 0x33, 0xc2, 0x1a, 0x40, 0x89, 0x26, 0xeb, 0x78, 0x51, 0x5a, 0x62, 0xa3, 0xee, 0x02, 0x8f, + 0x42, 0xa1, 0xe3, 0x3a, 0x41, 0x44, 0x93, 0xd3, 0x03, 0xda, 0xe2, 0x83, 0x69, 0xc5, 0xb3, 0xb6, + 0x91, 0x00, 0xa2, 0x32, 0x24, 0x88, 0x87, 0xab, 0x02, 0x28, 0x2a, 0x8b, 0x87, 0xab, 0x2b, 0x8b, + 0x13, 0x02, 0x03, 0x9a, 0x94, 0x13, 0x87, 0x0b, 0x1a, 0x98, 0x03, 0x1b, 0x10, 0x81, 0x1a, 0x9f, + 0x81, 0xa9, 0x03, 0x3a, 0x05, 0x06, 0x27, 0xab, 0x3b, 0xa8, 0x8a, 0xab, 0xaf, 0x0a, 0xaa, 0x2f, + 0x31, 0x39, 0x32, 0x3a, 0x81, 0xbf, 0x07, 0x87, 0x89, 0x98, 0xa2, 0x22, 0x13, 0xa4, 0xb6, 0x0e, + 0x43, 0xf2, 0x43, 0x33, 0x47, 0x4c, 0x66, 0x26, 0xf2, 0x69, 0x2b, 0x5a, 0xa3, 0x83, 0x4b, 0xe6, + 0x41, 0x50, 0x92, 0xcb, 0xd3, 0x1e, 0x57, 0x87, 0x01, 0x19, 0x9a, 0x52, 0x45, 0x5a, 0x9e, 0xde, + 0xa3, 0xa1, 0x42, 0x7b, 0xa3, 0x22, 0xa2, 0x87, 0x80, 0xe0, 0xf3, 0x23, 0x2a, 0x8e, 0x2f, 0x6f, + 0x92, 0x1a, 0x23, 0xab, 0xb3, 0x09, 0xd6, 0xab, 0x38, 0xe3, 0x2b, 0x3a, 0xdf, 0x7d, 0xea, 0x87, +}; + +const uint8_t cjdh2_key[0x100] = { + 0x03, 0x31, 0x92, 0x23, 0x21, 0x2b, 0x23, 0x23, 0x39, 0x01, 0xb2, 0x9b, 0x0d, 0xaa, 0x07, 0x86, + 0x03, 0x9b, 0x03, 0x82, 0x82, 0x00, 0x86, 0x0b, 0x80, 0x92, 0x9a, 0x1b, 0x81, 0x9a, 0x92, 0x8f, + 0x83, 0x89, 0x82, 0x0a, 0x02, 0x0f, 0x83, 0xa7, 0x80, 0x32, 0xbb, 0x02, 0x8f, 0xa2, 0xaa, 0x0e, + 0x80, 0x12, 0x23, 0xbb, 0x86, 0xb9, 0xb3, 0x1b, 0x19, 0xb8, 0x93, 0x22, 0x28, 0x9d, 0xbf, 0xb2, + 0xa1, 0xb0, 0x63, 0xaa, 0x81, 0x8a, 0x47, 0x0b, 0xdb, 0x21, 0x5a, 0x03, 0xe9, 0x60, 0x2f, 0xab, + 0x00, 0x43, 0xc2, 0x8b, 0x06, 0x54, 0x47, 0x9f, 0x51, 0xc9, 0x4a, 0x4b, 0x1f, 0x40, 0x9f, 0x52, + 0x21, 0x00, 0xe3, 0x72, 0x44, 0x43, 0xc2, 0xab, 0x5a, 0x32, 0x1a, 0x62, 0x6d, 0xa2, 0x82, 0xce, + 0x73, 0xe0, 0xc3, 0xa3, 0x73, 0x71, 0x16, 0x42, 0x69, 0xc9, 0x02, 0x43, 0x93, 0x23, 0x43, 0xbf, + 0x83, 0x19, 0xb2, 0x9a, 0xa0, 0x8a, 0x03, 0x8e, 0x29, 0x03, 0x02, 0x0b, 0xa0, 0xa0, 0x8b, 0x0a, + 0x13, 0x0b, 0x12, 0x9a, 0x10, 0x80, 0x87, 0x8f, 0x98, 0x89, 0x13, 0x0b, 0x83, 0x8e, 0x1a, 0x1a, + 0x90, 0xab, 0xa2, 0x9b, 0xa5, 0xae, 0x22, 0x0a, 0x8b, 0xab, 0xa3, 0x0a, 0x0e, 0x02, 0x8e, 0x0f, + 0x32, 0x3b, 0x13, 0x0b, 0x93, 0x91, 0x22, 0x0b, 0x90, 0xab, 0xb2, 0x33, 0xa1, 0x21, 0xaa, 0xae, + 0xa3, 0x93, 0x73, 0xc2, 0x67, 0x81, 0xc7, 0x0a, 0x31, 0xa2, 0x7b, 0x93, 0xa7, 0x60, 0x86, 0xce, + 0x53, 0x18, 0x53, 0x52, 0xc6, 0x5b, 0x47, 0x1a, 0x0b, 0x98, 0x5b, 0xda, 0x92, 0x14, 0x07, 0x82, + 0x70, 0xc3, 0x02, 0xd2, 0xe1, 0x42, 0x42, 0x47, 0xe3, 0x20, 0x9a, 0xea, 0xe6, 0x02, 0x2a, 0x8f, + 0xf3, 0x3a, 0x22, 0x7a, 0xf1, 0x58, 0x97, 0xeb, 0x41, 0x59, 0xe2, 0x73, 0xdd, 0xa7, 0x7e, 0x1f, +}; + +const uint8_t bubucar_key[0x100] = { + 0x01, 0x91, 0x31, 0x00, 0x83, 0x2e, 0x05, 0x0d, 0x02, 0x31, 0x91, 0x18, 0x21, 0x2e, 0xac, 0xad, + 0x93, 0x8b, 0x91, 0x11, 0x07, 0x99, 0x84, 0x0c, 0x8b, 0x03, 0x91, 0x01, 0x84, 0x94, 0x88, 0x95, + 0x10, 0x9b, 0x91, 0xb0, 0x87, 0x80, 0x04, 0x8d, 0x82, 0xb0, 0xb0, 0x30, 0x87, 0x25, 0x80, 0x29, + 0x91, 0x10, 0x01, 0x89, 0x27, 0x8a, 0x14, 0x31, 0xba, 0xba, 0x20, 0x91, 0xbc, 0x3b, 0x3c, 0xa1, + 0x72, 0x38, 0x10, 0xe1, 0xe2, 0x88, 0xa0, 0xed, 0xb9, 0xe8, 0xf0, 0x51, 0xa6, 0x6e, 0x40, 0x65, + 0x50, 0xc8, 0x80, 0x00, 0x41, 0xc7, 0x44, 0x9d, 0x80, 0x9b, 0x00, 0x99, 0x8c, 0x81, 0x10, 0x08, + 0x61, 0x61, 0x00, 0x39, 0xa6, 0xc7, 0x85, 0x25, 0x80, 0xb2, 0xb9, 0x10, 0xa2, 0x6a, 0xc1, 0x49, + 0xd1, 0xf0, 0xe0, 0xc9, 0x82, 0x87, 0xc4, 0xec, 0xf2, 0x90, 0x29, 0xe1, 0x5d, 0x6c, 0x41, 0x80, + 0x32, 0xaa, 0x80, 0x00, 0xa6, 0x26, 0x00, 0xa9, 0x82, 0x92, 0x30, 0xb1, 0x02, 0xa0, 0x84, 0xa5, + 0x80, 0x93, 0x90, 0x08, 0x06, 0x03, 0x15, 0x94, 0x0b, 0x83, 0x91, 0x10, 0x97, 0x17, 0x81, 0x81, + 0xa0, 0xa9, 0x10, 0xa8, 0xa7, 0x2d, 0x81, 0x05, 0x98, 0x9a, 0x88, 0x80, 0xaf, 0x81, 0x29, 0xad, + 0x20, 0xb9, 0xb0, 0xa9, 0xa4, 0x33, 0x31, 0x90, 0x90, 0x18, 0x88, 0x90, 0x21, 0xaf, 0x2c, 0x80, + 0x50, 0x58, 0x80, 0xb1, 0x20, 0x64, 0xe0, 0x2c, 0xc2, 0x48, 0xe1, 0x40, 0x60, 0x23, 0xc4, 0xe8, + 0x42, 0x8b, 0x50, 0x48, 0xd4, 0x0f, 0x00, 0xd0, 0x98, 0x41, 0xc0, 0x89, 0xc3, 0x0e, 0x9c, 0x1d, + 0xe1, 0xb2, 0xc0, 0x80, 0x43, 0x42, 0x41, 0xa8, 0x5b, 0xa3, 0x68, 0x40, 0xae, 0x60, 0x01, 0x24, + 0x31, 0xb3, 0xf0, 0xf8, 0x34, 0x8e, 0xc0, 0x94, 0xa8, 0xd8, 0x10, 0xa0, 0x46, 0x33, 0xe9, 0x38, +}; |