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Updates to SEGA's 315-5881 encryption based on new findings from Virtua Striker 2 '98 (Model3) [Andreas Naive]
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andreasnaive
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5bff739d72
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f16795fcd7
@ -6014,7 +6014,7 @@ ROM_START( wldkicks )
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ROM_LOAD( "wk1ma10.4c", 0xa000000, 0x1000000, CRC(e96f312c) SHA1(0a92640277111aef5c6e9dab4218a8ae2196ce61) )
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ROM_REGION( 4, "rom_key", 0 )
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ROM_LOAD( "wldkicks-key.bin", 0, 4, CRC(c1e3000b) SHA1(36c2546833effe9452e2b3f7d31335fc5e349f49) )
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ROM_LOAD( "wldkicks-key.bin", 0, 4, CRC(1708ebb9) SHA1(c1115e4dd675f10d5fb41f57c1eea8e6a4f09fed) )
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ROM_END
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ROM_START( wldkicksa )
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@ -6036,7 +6036,7 @@ ROM_START( wldkicksa )
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ROM_LOAD( "wk1ma10.4c", 0xa000000, 0x1000000, CRC(e96f312c) SHA1(0a92640277111aef5c6e9dab4218a8ae2196ce61) )
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ROM_REGION( 4, "rom_key", 0 )
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ROM_LOAD( "wldkicks-key.bin", 0, 4, CRC(c1e3000b) SHA1(36c2546833effe9452e2b3f7d31335fc5e349f49) )
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ROM_LOAD( "wldkicks-key.bin", 0, 4, CRC(1708ebb9) SHA1(c1115e4dd675f10d5fb41f57c1eea8e6a4f09fed) )
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ROM_END
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ROM_START( wldkicksb )
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@ -6058,7 +6058,7 @@ ROM_START( wldkicksb )
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ROM_LOAD( "wk1ma10.4c", 0xa000000, 0x1000000, CRC(e96f312c) SHA1(0a92640277111aef5c6e9dab4218a8ae2196ce61) )
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ROM_REGION( 4, "rom_key", 0 )
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ROM_LOAD( "wldkicks-key.bin", 0, 4, CRC(c1e3000b) SHA1(36c2546833effe9452e2b3f7d31335fc5e349f49) )
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ROM_LOAD( "wldkicks-key.bin", 0, 4, CRC(1708ebb9) SHA1(c1115e4dd675f10d5fb41f57c1eea8e6a4f09fed) )
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ROM_END
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ROM_START( toukon4 )
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@ -6085,7 +6085,7 @@ ROM_START( toukon4 )
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ROM_LOAD( "trf1ma15.6l", 0xf000000, 0x1000000, CRC(42d318c5) SHA1(f9fe82ffbfc51fcb52333f94c55a7092e7124fb4) )
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ROM_REGION( 4, "rom_key", 0 )
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ROM_LOAD( "tr4ae-key.bin", 0x000000, 0x000004, CRC(986a7cee) SHA1(70c3ff80f86de6a0655251658c66a156fb644995) )
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ROM_LOAD( "tr4ae-key.bin", 0x000000, 0x000004, CRC(1708ebb9) SHA1(c1115e4dd675f10d5fb41f57c1eea8e6a4f09fed) )
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ROM_END
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ROM_START( ninjaslt )
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@ -7805,7 +7805,7 @@ ROM_START( vstrik3c )
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ROM_LOAD( "mpr-23662.ic11", 0xa800000, 0x0800000, CRC(d6ef7d68) SHA1(4ee396af6c5caf4c5af6e9ad0e03a7ac2c5039f4) )
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ROM_REGION( 4, "rom_key", 0 )
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ROM_LOAD( "vstrik3c-key.bin", 0, 4, CRC(049f41b0) SHA1(4ea444878c8e9288ec95b1763d48bc92c634acdd) )
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ROM_LOAD( "vstrik3c-key.bin", 0, 4, CRC(8c9012fe) SHA1(d81e00d6377a3f0eeed01dc523707e36ca1b434d) )
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ROM_END
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ROM_START( vstrik3cb )
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@ -7827,7 +7827,7 @@ ROM_START( vstrik3cb )
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ROM_LOAD( "mpr-23662.ic11", 0xa800000, 0x0800000, CRC(d6ef7d68) SHA1(4ee396af6c5caf4c5af6e9ad0e03a7ac2c5039f4) )
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ROM_REGION( 4, "rom_key", 0 )
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ROM_LOAD( "vstrik3c-key.bin", 0, 4, CRC(049f41b0) SHA1(4ea444878c8e9288ec95b1763d48bc92c634acdd) )
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ROM_LOAD( "vstrik3c-key.bin", 0, 4, CRC(8c9012fe) SHA1(d81e00d6377a3f0eeed01dc523707e36ca1b434d) )
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ROM_END
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ROM_START( wldrider )
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@ -7870,7 +7870,7 @@ ROM_START( vf4cart )
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ROM_LOAD( "mpr-23784.ic11", 0xa800000, 0x1000000, CRC(f74f2fee) SHA1(84b07baa6d116727e66ef27e24ba6484c3393891) )
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ROM_REGION( 4, "rom_key", 0 )
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ROM_LOAD( "vf4cart-key.bin", 0, 4, CRC(22838e16) SHA1(afee674dce3cfdd20360c30da2da5ba69f8d4682) )
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ROM_LOAD( "vf4cart-key.bin", 0, 4, CRC(aa8cdd58) SHA1(e282b7d215044a005b50c8553b8056f3d599135c) )
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ROM_END
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// There is also a development cart (171-7885A) with 20x 64Mb FlashROMs instead of 10x 128Mb MaskROMs. Content is the same.
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@ -121,7 +121,7 @@ Notes below refer to M2 & M3.
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The encryption is done by a stream cipher operating in counter mode, which use a 16-bits internal block cipher.
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There are 2 "control bits" at the start of the decrypted stream which control the mode of operation: bit #1 set to 1 means
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that the decrypted stream needs to be decompressed after being decrypted. More on this later.
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that the stream needs to be decompressed after being decrypted. More on this later.
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The next 16-bits are part of the header (they don't belong to the plaintext), but his meaning is unclear. It has been
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conjectured that it could stablish when to "reset" the process and start processing a new stream (based on some tests
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@ -134,12 +134,12 @@ internal block-cipher. So, at a given step, the internal block cipher will outpu
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given plaintext word, and the remaining 2 to the next plaintext word.
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The underlying block cipher consists of two 4-round Feistel Networks (FN): the first one takes the counter (16 bits),
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the game-key (>=26 bits) and the sequence-key (16 bits) and output a middle result (16 bits) which will act as another key
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the game-key (>=27 bits) and the sequence-key (16 bits) and output a middle result (16 bits) which will act as another key
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for the second one. The second FN will take the encrypted word (16 bits), the game-key, the sequence-key and the result
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from the first FN and will output the decrypted word (16 bits).
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Each round of the Feistel Networks use four substitution sboxes, each having 6 inputs and 2 outputs. The input can be the
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XOR of at most two "sources bits", being source bits the bits from the previous round and the bits from the different keys.
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Each round of the Feistel Networks use four substitution sboxes, each having 6 inputs and 2 outputs. The input is the
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XOR of at most one bit from the previous round and at most one bit from the different keys.
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The underlying block cipher has the same structure than the one used by the CPS-2 (Capcom Play System 2) and,
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indeed, some of the used sboxes are exactly the same and appear in the same FN/round in both systems (this is not evident,
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@ -151,10 +151,6 @@ Due to the small key-length, no sophisticated attacks are needed to recover the
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some (encrypted word-decrypted word) pairs suffice. However, due to the weak key scheduling, it should be noted that some
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related keys can produce the same output bytes for some (short) input sequences.
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The only difference in the decryption process between M2 and M3 is the initialization of the counter. In M3, the counter is
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always set to 0 at the beginning of the decryption while, in M2, the bits #1-#16 of the ciphertext's address are used
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to initialize the counter.
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Note that this implementation considers that the counter initialization for ram decryption is 0 simply because the ram is
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mapped to multiples of 128K.
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@ -164,7 +160,7 @@ accordingly the s-boxes' definitions. So the order of the bits in the keys is ar
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chosen so as to make the key for CAPSNK equal to 0.
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It can be observed that a couple of sboxes have incomplete tables (a 255 value indicate an unknown value). The recovered keys
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as of december/2010 show small randomness and big correlations, making possible that some unseen bits could make the
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as of january/2015 show small randomness and big correlations, making possible that some unseen bits could make the
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decryption need those incomplete parts.
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****************************************************************************************/
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@ -478,16 +474,16 @@ const int sega_315_5881_crypt_device::fn1_game_key_scheduling[38][2] = {
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{1,29}, {1,71}, {2,4}, {2,54}, {3,8}, {4,56}, {4,73}, {5,11},
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{6,51}, {7,92}, {8,89}, {9,9}, {9,10}, {9,39}, {9,41}, {9,58},
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{9,59}, {9,86}, {10,90}, {11,6}, {12,64}, {13,49}, {14,44}, {15,40},
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{16,69}, {17,15}, {18,23}, {18,43}, {19,82}, {20,81}, {21,32}, {21,61},
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{22,5}, {23,66}, {24,13}, {24,45}, {25,12}, {25,35}
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{16,69}, {17,15}, {18,23}, {18,43}, {19,82}, {20,81}, {21,32}, {22,5},
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{23,66}, {24,13}, {24,45}, {25,12}, {25,35}, {26,61},
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};
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const int sega_315_5881_crypt_device::fn2_game_key_scheduling[34][2] = {
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{0,0}, {1,3}, {2,11}, {3,20}, {4,22}, {5,23}, {6,29}, {7,38},
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{8,39}, {9,47}, {9,55}, {9,86}, {9,87}, {9,90}, {10,50}, {10,53},
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{11,57}, {12,59}, {13,61}, {13,64}, {14,63}, {15,67}, {16,72}, {17,83},
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{18,88}, {19,94}, {20,35}, {21,17}, {21,92}, {22,6}, {22,11}, {23,85},
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{24,16}, {25,25}
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{18,88}, {19,94}, {20,35}, {21,17}, {22,6}, {22,11}, {23,85}, {24,16},
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{25,25}, {26,92}
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};
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const int sega_315_5881_crypt_device::fn1_sequence_key_scheduling[20][2] = {
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@ -28,8 +28,8 @@ static const struct game_keys keys_table[] =
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{
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// name key gameid # year
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// M2
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{ "wldkicks", 0x00ae2901 }, // 25209801 2000
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{ "toukon4", 0x012e2901 }, // 25349801 2000
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{ "wldkicks", 0x052e2901 }, // 25209801 2000
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{ "toukon4", 0x052e2901 }, // 25349801 2000
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{ "ninjaslt", 0x000ca510 }, // 25469801 2000
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{ "ninjaslt4", 0x000ca510 }, // 25469801 2000
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{ "gunsur2e", 0x000680d0 }, // 25709801 2001
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@ -68,7 +68,7 @@ static const struct game_keys keys_table[] =
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{ "alienfnt", 0x00174343 }, // 840-0048 2001
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{ "alienfnta", 0x00174343 }, // 840-0048 2001
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{ "crackdj2", 0x00428247 }, // 840-0068 2001
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{ "vf4cart", 0x02ef2f96 }, // 840-0080 2002
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{ "vf4cart", 0x06ef2f92 }, // 840-0080 2002
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{ "pstone", 0x000e69c1 }, // 841-0001 1999
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{ "suchie3", 0x000368e1 }, // 841-0002 1999
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{ "doa2", 0x0008ad01 }, // 841-0003 1999
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