djiparsetxt
scrambleBytes.cpp
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1 /**********
2 This program is free software: you can redistribute it and/or modify
3 it under the terms of the GNU General Public License as published by
4 the Free Software Foundation, either version 3 of the License, or
5 (at your option) any later version.
6 
7 This program is distributed in the hope that it will be useful,
8 but WITHOUT ANY WARRANTY; without even the implied warranty of
9 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
10 GNU General Public License for more details.
11 
12 You should have received a copy of the GNU General Public License
13 along with this program. If not, see <http://www.gnu.org/licenses/>.
14 **********/
15 /*
16  A C++ program to parse DJI's ".txt" log files (recorded by the "DJI Go 4" app).
17  Version 2020-09-25
18 
19  Copyright (c) 2020 Live Networks, Inc. All rights reserved.
20  For the latest version of this program (and more information), visit http://djilogs.live555.com
21 
22  Get an array of 8 bytes that were used to scramble (i.e., obfuscate) record data.
23  Implementation.
24 */
25 
26 #include "scrambleBytes.hh"
27 
28 static u_int64_t crc64Table[256] = {0x0,
29 0x7AD870C830358979, 0xF5B0E190606B12F2, 0x8F689158505E9B8B,
30 0xC038E5739841B68F, 0xBAE095BBA8743FF6, 0x358804E3F82AA47D,
31 0x4F50742BC81F2D04, 0xAB28ECB46814FE75, 0xD1F09C7C5821770C,
32 0x5E980D24087FEC87, 0x24407DEC384A65FE, 0x6B1009C7F05548FA,
33 0x11C8790FC060C183, 0x9EA0E857903E5A08, 0xE478989FA00BD371,
34 0x7D08FF3B88BE6F81, 0x7D08FF3B88BE6F8, 0x88B81EABE8D57D73,
35 0xF2606E63D8E0F40A, 0xBD301A4810FFD90E, 0xC7E86A8020CA5077,
36 0x4880FBD87094CBFC, 0x32588B1040A14285, 0xD620138FE0AA91F4,
37 0xACF86347D09F188D, 0x2390F21F80C18306, 0x594882D7B0F40A7F,
38 0x1618F6FC78EB277B, 0x6CC0863448DEAE02, 0xE3A8176C18803589,
39 0x997067A428B5BCF0, 0xFA11FE77117CDF02, 0x80C98EBF2149567B,
40 0xFA11FE77117CDF0, 0x75796F2F41224489, 0x3A291B04893D698D,
41 0x40F16BCCB908E0F4, 0xCF99FA94E9567B7F, 0xB5418A5CD963F206,
42 0x513912C379682177, 0x2BE1620B495DA80E, 0xA489F35319033385,
43 0xDE51839B2936BAFC, 0x9101F7B0E12997F8, 0xEBD98778D11C1E81,
44 0x64B116208142850A, 0x1E6966E8B1770C73, 0x8719014C99C2B083,
45 0xFDC17184A9F739FA, 0x72A9E0DCF9A9A271, 0x8719014C99C2B08,
46 0x4721E43F0183060C, 0x3DF994F731B68F75, 0xB29105AF61E814FE,
47 0xC849756751DD9D87, 0x2C31EDF8F1D64EF6, 0x56E99D30C1E3C78F,
48 0xD9810C6891BD5C04, 0xA3597CA0A188D57D, 0xEC09088B6997F879,
49 0x96D1784359A27100, 0x19B9E91B09FCEA8B, 0x636199D339C963F2,
50 0xDF7ADABD7A6E2D6F, 0xA5A2AA754A5BA416, 0x2ACA3B2D1A053F9D,
51 0x50124BE52A30B6E4, 0x1F423FCEE22F9BE0, 0x659A4F06D21A1299,
52 0xEAF2DE5E82448912, 0x902AAE96B271006B, 0x74523609127AD31A,
53 0xE8A46C1224F5A63, 0x81E2D7997211C1E8, 0xFB3AA75142244891,
54 0xB46AD37A8A3B6595, 0xCEB2A3B2BA0EECEC, 0x41DA32EAEA507767,
55 0x3B024222DA65FE1E, 0xA2722586F2D042EE, 0xD8AA554EC2E5CB97,
56 0x57C2C41692BB501C, 0x2D1AB4DEA28ED965, 0x624AC0F56A91F461,
57 0x1892B03D5AA47D18, 0x97FA21650AFAE693, 0xED2251AD3ACF6FEA,
58 0x95AC9329AC4BC9B, 0x7382B9FAAAF135E2, 0xFCEA28A2FAAFAE69,
59 0x8632586ACA9A2710, 0xC9622C4102850A14, 0xB3BA5C8932B0836D,
60 0x3CD2CDD162EE18E6, 0x460ABD1952DB919F, 0x256B24CA6B12F26D,
61 0x5FB354025B277B14, 0xD0DBC55A0B79E09F, 0xAA03B5923B4C69E6,
62 0xE553C1B9F35344E2, 0x9F8BB171C366CD9B, 0x10E3202993385610,
63 0x6A3B50E1A30DDF69, 0x8E43C87E03060C18, 0xF49BB8B633338561,
64 0x7BF329EE636D1EEA, 0x12B592653589793, 0x4E7B2D0D9B47BA97,
65 0x34A35DC5AB7233EE, 0xBBCBCC9DFB2CA865, 0xC113BC55CB19211C,
66 0x5863DBF1E3AC9DEC, 0x22BBAB39D3991495, 0xADD33A6183C78F1E,
67 0xD70B4AA9B3F20667, 0x985B3E827BED2B63, 0xE2834E4A4BD8A21A,
68 0x6DEBDF121B863991, 0x1733AFDA2BB3B0E8, 0xF34B37458BB86399,
69 0x8993478DBB8DEAE0, 0x6FBD6D5EBD3716B, 0x7C23A61DDBE6F812,
70 0x3373D23613F9D516, 0x49ABA2FE23CC5C6F, 0xC6C333A67392C7E4,
71 0xBC1B436E43A74E9D, 0x95AC9329AC4BC9B5, 0xEF74E3E19C7E40CC,
72 0x601C72B9CC20DB47, 0x1AC40271FC15523E, 0x5594765A340A7F3A,
73 0x2F4C0692043FF643, 0xA02497CA54616DC8, 0xDAFCE7026454E4B1,
74 0x3E847F9DC45F37C0, 0x445C0F55F46ABEB9, 0xCB349E0DA4342532,
75 0xB1ECEEC59401AC4B, 0xFEBC9AEE5C1E814F, 0x8464EA266C2B0836,
76 0xB0C7B7E3C7593BD, 0x71D40BB60C401AC4, 0xE8A46C1224F5A634,
77 0x927C1CDA14C02F4D, 0x1D148D82449EB4C6, 0x67CCFD4A74AB3DBF,
78 0x289C8961BCB410BB, 0x5244F9A98C8199C2, 0xDD2C68F1DCDF0249,
79 0xA7F41839ECEA8B30, 0x438C80A64CE15841, 0x3954F06E7CD4D138,
80 0xB63C61362C8A4AB3, 0xCCE411FE1CBFC3CA, 0x83B465D5D4A0EECE,
81 0xF96C151DE49567B7, 0x76048445B4CBFC3C, 0xCDCF48D84FE7545,
82 0x6FBD6D5EBD3716B7, 0x15651D968D029FCE, 0x9A0D8CCEDD5C0445,
83 0xE0D5FC06ED698D3C, 0xAF85882D2576A038, 0xD55DF8E515432941,
84 0x5A3569BD451DB2CA, 0x20ED197575283BB3, 0xC49581EAD523E8C2,
85 0xBE4DF122E51661BB, 0x3125607AB548FA30, 0x4BFD10B2857D7349,
86 0x4AD64994D625E4D, 0x7E7514517D57D734, 0xF11D85092D094CBF,
87 0x8BC5F5C11D3CC5C6, 0x12B5926535897936, 0x686DE2AD05BCF04F,
88 0xE70573F555E26BC4, 0x9DDD033D65D7E2BD, 0xD28D7716ADC8CFB9,
89 0xA85507DE9DFD46C0, 0x273D9686CDA3DD4B, 0x5DE5E64EFD965432,
90 0xB99D7ED15D9D8743, 0xC3450E196DA80E3A, 0x4C2D9F413DF695B1,
91 0x36F5EF890DC31CC8, 0x79A59BA2C5DC31CC, 0x37DEB6AF5E9B8B5,
92 0x8C157A32A5B7233E, 0xF6CD0AFA9582AA47, 0x4AD64994D625E4DA,
93 0x300E395CE6106DA3, 0xBF66A804B64EF628, 0xC5BED8CC867B7F51,
94 0x8AEEACE74E645255, 0xF036DC2F7E51DB2C, 0x7F5E4D772E0F40A7,
95 0x5863DBF1E3AC9DE, 0xE1FEA520BE311AAF, 0x9B26D5E88E0493D6,
96 0x144E44B0DE5A085D, 0x6E963478EE6F8124, 0x21C640532670AC20,
97 0x5B1E309B16452559, 0xD476A1C3461BBED2, 0xAEAED10B762E37AB,
98 0x37DEB6AF5E9B8B5B, 0x4D06C6676EAE0222, 0xC26E573F3EF099A9,
99 0xB8B627F70EC510D0, 0xF7E653DCC6DA3DD4, 0x8D3E2314F6EFB4AD,
100 0x256B24CA6B12F26, 0x788EC2849684A65F, 0x9CF65A1B368F752E,
101 0xE62E2AD306BAFC57, 0x6946BB8B56E467DC, 0x139ECB4366D1EEA5,
102 0x5CCEBF68AECEC3A1, 0x2616CFA09EFB4AD8, 0xA97E5EF8CEA5D153,
103 0xD3A62E30FE90582A, 0xB0C7B7E3C7593BD8, 0xCA1FC72BF76CB2A1,
104 0x45775673A732292A, 0x3FAF26BB9707A053, 0x70FF52905F188D57,
105 0xA2722586F2D042E, 0x854FB3003F739FA5, 0xFF97C3C80F4616DC,
106 0x1BEF5B57AF4DC5AD, 0x61372B9F9F784CD4, 0xEE5FBAC7CF26D75F,
107 0x9487CA0FFF135E26, 0xDBD7BE24370C7322, 0xA10FCEEC0739FA5B,
108 0x2E675FB4576761D0, 0x54BF2F7C6752E8A9, 0xCDCF48D84FE75459,
109 0xB71738107FD2DD20, 0x387FA9482F8C46AB, 0x42A7D9801FB9CFD2,
110 0xDF7ADABD7A6E2D6, 0x772FDD63E7936BAF, 0xF8474C3BB7CDF024,
111 0x829F3CF387F8795D, 0x66E7A46C27F3AA2C, 0x1C3FD4A417C62355,
112 0x935745FC4798B8DE, 0xE98F353477AD31A7, 0xA6DF411FBFB21CA3,
113 0xDC0731D78F8795DA, 0x536FA08FDFD90E51, 0x29B7D047EFEC8728
114 };
115 
116 static u_int64_t crc64(u_int8_t seed, u_int8_t const* buffer, unsigned bufferSize) {
117  u_int64_t crc = seed;
118 
119  for (unsigned i = 0; i < bufferSize; ++i) {
120  u_int8_t tabIndex = buffer[i] ^ crc;
121  crc = crc64Table[tabIndex] ^ (crc >> 8);
122  }
123 
124  return crc;
125 }
126 
127 void getScrambleBytes(u_int8_t recordType, u_int8_t keyByte,
128  u_int8_t* resultScrambleBytes) {
129  // Set up the (8-byte) buffer to compute the CRC over:
130  u_int64_t dataForBuffer = 0x123456789ABCDEF0*keyByte;
131  u_int8_t bufferToCRC[8];
132  // Fill in the buffer in little-endian order:
133  for (unsigned i = 0; i < sizeof bufferToCRC; ++i) {
134  bufferToCRC[i] = dataForBuffer; // low 8 bits
135  dataForBuffer >>= 8;
136  }
137 
138  // Compute a CRC over this buffer, using our "recordType" and "keyByte" parameters as salt:
139  u_int64_t crcResult = crc64(recordType + keyByte, bufferToCRC, sizeof bufferToCRC);
140 
141  // Unpack this into "resultScrambleBytes", in little-endian order:
142  for (unsigned i = 0; i < 8; ++i) {
143  resultScrambleBytes[i] = crcResult; // low 8 bits
144  crcResult >>= 8;
145  }
146 }
static u_int64_t crc64(u_int8_t seed, u_int8_t const *buffer, unsigned bufferSize)
void getScrambleBytes(u_int8_t recordType, u_int8_t keyByte, u_int8_t *resultScrambleBytes)
static u_int64_t crc64Table[256]