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Updates to SEGA's 315-5881 encryption based on new findings from Virt…
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…ua Striker 2 '98 (Model3) [Andreas Naive]
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andreasnaive committed Jan 18, 2015
1 parent 5bff739 commit f16795f
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Showing 3 changed files with 19 additions and 23 deletions.
14 changes: 7 additions & 7 deletions src/mame/drivers/naomi.c
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Original file line number Diff line number Diff line change
Expand Up @@ -6014,7 +6014,7 @@ ROM_START( wldkicks )
ROM_LOAD( "wk1ma10.4c", 0xa000000, 0x1000000, CRC(e96f312c) SHA1(0a92640277111aef5c6e9dab4218a8ae2196ce61) )

ROM_REGION( 4, "rom_key", 0 )
ROM_LOAD( "wldkicks-key.bin", 0, 4, CRC(c1e3000b) SHA1(36c2546833effe9452e2b3f7d31335fc5e349f49) )
ROM_LOAD( "wldkicks-key.bin", 0, 4, CRC(1708ebb9) SHA1(c1115e4dd675f10d5fb41f57c1eea8e6a4f09fed) )
ROM_END

ROM_START( wldkicksa )
Expand All @@ -6036,7 +6036,7 @@ ROM_START( wldkicksa )
ROM_LOAD( "wk1ma10.4c", 0xa000000, 0x1000000, CRC(e96f312c) SHA1(0a92640277111aef5c6e9dab4218a8ae2196ce61) )

ROM_REGION( 4, "rom_key", 0 )
ROM_LOAD( "wldkicks-key.bin", 0, 4, CRC(c1e3000b) SHA1(36c2546833effe9452e2b3f7d31335fc5e349f49) )
ROM_LOAD( "wldkicks-key.bin", 0, 4, CRC(1708ebb9) SHA1(c1115e4dd675f10d5fb41f57c1eea8e6a4f09fed) )
ROM_END

ROM_START( wldkicksb )
Expand All @@ -6058,7 +6058,7 @@ ROM_START( wldkicksb )
ROM_LOAD( "wk1ma10.4c", 0xa000000, 0x1000000, CRC(e96f312c) SHA1(0a92640277111aef5c6e9dab4218a8ae2196ce61) )

ROM_REGION( 4, "rom_key", 0 )
ROM_LOAD( "wldkicks-key.bin", 0, 4, CRC(c1e3000b) SHA1(36c2546833effe9452e2b3f7d31335fc5e349f49) )
ROM_LOAD( "wldkicks-key.bin", 0, 4, CRC(1708ebb9) SHA1(c1115e4dd675f10d5fb41f57c1eea8e6a4f09fed) )
ROM_END

ROM_START( toukon4 )
Expand All @@ -6085,7 +6085,7 @@ ROM_START( toukon4 )
ROM_LOAD( "trf1ma15.6l", 0xf000000, 0x1000000, CRC(42d318c5) SHA1(f9fe82ffbfc51fcb52333f94c55a7092e7124fb4) )

ROM_REGION( 4, "rom_key", 0 )
ROM_LOAD( "tr4ae-key.bin", 0x000000, 0x000004, CRC(986a7cee) SHA1(70c3ff80f86de6a0655251658c66a156fb644995) )
ROM_LOAD( "tr4ae-key.bin", 0x000000, 0x000004, CRC(1708ebb9) SHA1(c1115e4dd675f10d5fb41f57c1eea8e6a4f09fed) )
ROM_END

ROM_START( ninjaslt )
Expand Down Expand Up @@ -7805,7 +7805,7 @@ ROM_START( vstrik3c )
ROM_LOAD( "mpr-23662.ic11", 0xa800000, 0x0800000, CRC(d6ef7d68) SHA1(4ee396af6c5caf4c5af6e9ad0e03a7ac2c5039f4) )

ROM_REGION( 4, "rom_key", 0 )
ROM_LOAD( "vstrik3c-key.bin", 0, 4, CRC(049f41b0) SHA1(4ea444878c8e9288ec95b1763d48bc92c634acdd) )

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@p1pkin

p1pkin Jan 18, 2015

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are you sure this is not mistake and Naomi 2 Virtua Striker 3 key is updated ?

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@p1pkin

p1pkin Jan 18, 2015

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thanks for explanation. in that case you are right - vstrik3c is affected, also must be updated clubkrte and wldrider keys.
ROM_LOAD( "vstrik3c-key.bin", 0, 4, CRC(8c9012fe) SHA1(d81e00d6377a3f0eeed01dc523707e36ca1b434d) )
ROM_END

ROM_START( vstrik3cb )
Expand All @@ -7827,7 +7827,7 @@ ROM_START( vstrik3cb )
ROM_LOAD( "mpr-23662.ic11", 0xa800000, 0x0800000, CRC(d6ef7d68) SHA1(4ee396af6c5caf4c5af6e9ad0e03a7ac2c5039f4) )

ROM_REGION( 4, "rom_key", 0 )
ROM_LOAD( "vstrik3c-key.bin", 0, 4, CRC(049f41b0) SHA1(4ea444878c8e9288ec95b1763d48bc92c634acdd) )
ROM_LOAD( "vstrik3c-key.bin", 0, 4, CRC(8c9012fe) SHA1(d81e00d6377a3f0eeed01dc523707e36ca1b434d) )
ROM_END

ROM_START( wldrider )
Expand Down Expand Up @@ -7870,7 +7870,7 @@ ROM_START( vf4cart )
ROM_LOAD( "mpr-23784.ic11", 0xa800000, 0x1000000, CRC(f74f2fee) SHA1(84b07baa6d116727e66ef27e24ba6484c3393891) )

ROM_REGION( 4, "rom_key", 0 )
ROM_LOAD( "vf4cart-key.bin", 0, 4, CRC(22838e16) SHA1(afee674dce3cfdd20360c30da2da5ba69f8d4682) )
ROM_LOAD( "vf4cart-key.bin", 0, 4, CRC(aa8cdd58) SHA1(e282b7d215044a005b50c8553b8056f3d599135c) )
ROM_END

// There is also a development cart (171-7885A) with 20x 64Mb FlashROMs instead of 10x 128Mb MaskROMs. Content is the same.
Expand Down
22 changes: 9 additions & 13 deletions src/mame/machine/315-5881_crypt.c
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Original file line number Diff line number Diff line change
Expand Up @@ -121,7 +121,7 @@ Notes below refer to M2 & M3.
The encryption is done by a stream cipher operating in counter mode, which use a 16-bits internal block cipher.
There are 2 "control bits" at the start of the decrypted stream which control the mode of operation: bit #1 set to 1 means
that the decrypted stream needs to be decompressed after being decrypted. More on this later.
that the stream needs to be decompressed after being decrypted. More on this later.
The next 16-bits are part of the header (they don't belong to the plaintext), but his meaning is unclear. It has been
conjectured that it could stablish when to "reset" the process and start processing a new stream (based on some tests
Expand All @@ -134,12 +134,12 @@ internal block-cipher. So, at a given step, the internal block cipher will outpu
given plaintext word, and the remaining 2 to the next plaintext word.
The underlying block cipher consists of two 4-round Feistel Networks (FN): the first one takes the counter (16 bits),
the game-key (>=26 bits) and the sequence-key (16 bits) and output a middle result (16 bits) which will act as another key
the game-key (>=27 bits) and the sequence-key (16 bits) and output a middle result (16 bits) which will act as another key
for the second one. The second FN will take the encrypted word (16 bits), the game-key, the sequence-key and the result
from the first FN and will output the decrypted word (16 bits).
Each round of the Feistel Networks use four substitution sboxes, each having 6 inputs and 2 outputs. The input can be the
XOR of at most two "sources bits", being source bits the bits from the previous round and the bits from the different keys.
Each round of the Feistel Networks use four substitution sboxes, each having 6 inputs and 2 outputs. The input is the
XOR of at most one bit from the previous round and at most one bit from the different keys.
The underlying block cipher has the same structure than the one used by the CPS-2 (Capcom Play System 2) and,
indeed, some of the used sboxes are exactly the same and appear in the same FN/round in both systems (this is not evident,
Expand All @@ -151,10 +151,6 @@ Due to the small key-length, no sophisticated attacks are needed to recover the
some (encrypted word-decrypted word) pairs suffice. However, due to the weak key scheduling, it should be noted that some
related keys can produce the same output bytes for some (short) input sequences.
The only difference in the decryption process between M2 and M3 is the initialization of the counter. In M3, the counter is
always set to 0 at the beginning of the decryption while, in M2, the bits #1-#16 of the ciphertext's address are used
to initialize the counter.
Note that this implementation considers that the counter initialization for ram decryption is 0 simply because the ram is
mapped to multiples of 128K.
Expand All @@ -164,7 +160,7 @@ accordingly the s-boxes' definitions. So the order of the bits in the keys is ar
chosen so as to make the key for CAPSNK equal to 0.
It can be observed that a couple of sboxes have incomplete tables (a 255 value indicate an unknown value). The recovered keys
as of december/2010 show small randomness and big correlations, making possible that some unseen bits could make the
as of january/2015 show small randomness and big correlations, making possible that some unseen bits could make the
decryption need those incomplete parts.
****************************************************************************************/
Expand Down Expand Up @@ -478,16 +474,16 @@ const int sega_315_5881_crypt_device::fn1_game_key_scheduling[38][2] = {
{1,29}, {1,71}, {2,4}, {2,54}, {3,8}, {4,56}, {4,73}, {5,11},
{6,51}, {7,92}, {8,89}, {9,9}, {9,10}, {9,39}, {9,41}, {9,58},
{9,59}, {9,86}, {10,90}, {11,6}, {12,64}, {13,49}, {14,44}, {15,40},
{16,69}, {17,15}, {18,23}, {18,43}, {19,82}, {20,81}, {21,32}, {21,61},
{22,5}, {23,66}, {24,13}, {24,45}, {25,12}, {25,35}
{16,69}, {17,15}, {18,23}, {18,43}, {19,82}, {20,81}, {21,32}, {22,5},
{23,66}, {24,13}, {24,45}, {25,12}, {25,35}, {26,61},
};

const int sega_315_5881_crypt_device::fn2_game_key_scheduling[34][2] = {
{0,0}, {1,3}, {2,11}, {3,20}, {4,22}, {5,23}, {6,29}, {7,38},
{8,39}, {9,47}, {9,55}, {9,86}, {9,87}, {9,90}, {10,50}, {10,53},
{11,57}, {12,59}, {13,61}, {13,64}, {14,63}, {15,67}, {16,72}, {17,83},
{18,88}, {19,94}, {20,35}, {21,17}, {21,92}, {22,6}, {22,11}, {23,85},
{24,16}, {25,25}
{18,88}, {19,94}, {20,35}, {21,17}, {22,6}, {22,11}, {23,85}, {24,16},
{25,25}, {26,92}
};

const int sega_315_5881_crypt_device::fn1_sequence_key_scheduling[20][2] = {
Expand Down
6 changes: 3 additions & 3 deletions src/mame/machine/naomicrypt.c
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Original file line number Diff line number Diff line change
Expand Up @@ -28,8 +28,8 @@ static const struct game_keys keys_table[] =
{
// name key gameid # year
// M2
{ "wldkicks", 0x00ae2901 }, // 25209801 2000
{ "toukon4", 0x012e2901 }, // 25349801 2000
{ "wldkicks", 0x052e2901 }, // 25209801 2000
{ "toukon4", 0x052e2901 }, // 25349801 2000
{ "ninjaslt", 0x000ca510 }, // 25469801 2000
{ "ninjaslt4", 0x000ca510 }, // 25469801 2000
{ "gunsur2e", 0x000680d0 }, // 25709801 2001
Expand Down Expand Up @@ -68,7 +68,7 @@ static const struct game_keys keys_table[] =
{ "alienfnt", 0x00174343 }, // 840-0048 2001
{ "alienfnta", 0x00174343 }, // 840-0048 2001
{ "crackdj2", 0x00428247 }, // 840-0068 2001
{ "vf4cart", 0x02ef2f96 }, // 840-0080 2002
{ "vf4cart", 0x06ef2f92 }, // 840-0080 2002
{ "pstone", 0x000e69c1 }, // 841-0001 1999
{ "suchie3", 0x000368e1 }, // 841-0002 1999
{ "doa2", 0x0008ad01 }, // 841-0003 1999
Expand Down

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