├── README.md
└── decrypt.cpp


/README.md:
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 1 | # Honkai-Appdata-Decryptor
 2 | A tool to decrypt .unity3d file located in Appdata/LocalLow/miHoYo/Honkai Impact 3/Data/data/...
 3 | 
 4 | 用于解密Appdata/LocalLow/miHoYo/崩坏3/Data/data/...下的unity3d文件的小工具
 5 | 
 6 | Only applicable to files starting with a number.
 7 | 
 8 | 仅适用于以数字开头的文件。
 9 | 
10 | Usage: decrypt.exe [input] [output]
11 | 


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/decrypt.cpp:
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  1 | #define _CRT_SECURE_NO_WARNINGS
  2 | #include <cstdlib>
  3 | #include <cstdio>
  4 | #include <cstring>
  5 | 
  6 | int box[624];
  7 | int v3 = 0;
  8 | void init(int seed)
  9 | {
 10 |     box[0] = seed;
 11 |     for (long long i = 1; i != 624; ++i)
 12 |     {
 13 |         box[i] = i + 1812433253 * (box[i - 1] ^ (unsigned int)(box[i - 1] >> 30));;
 14 |     }
 15 | }
 16 | int getInt()
 17 | {
 18 |     if (v3 == 0)
 19 |     {
 20 |         int v2 = 0;
 21 |         while (1)
 22 |         {
 23 |             int v5 = (v2 + 1) % 624;
 24 |             int v6 = (box[v2]) ^ ((box[v2]) ^ (box[v5])) & 0x7FFFFFFF;
 25 |             int v7 = (v2 + 397) % 624;
 26 |             box[v2] = (v6 >> 1) ^ box[v7];
 27 |             if ((v6 & 1) != 0)
 28 |             {
 29 |                 box[v2] ^= 0x9908B0DF;
 30 |             }
 31 |             if (++v2 == 624)
 32 |                 break;
 33 |         }
 34 |     }
 35 |     int v4 = box[v3];
 36 |     int v5 = v3 + 1;
 37 |     long long v6 = ((((v4 >> 11) ^ v4) & 0xFF3A58AD) << 7) ^ (v4 >> 11) ^ v4;
 38 |     long long v7 = (int)((unsigned long long)(3524075731LL * ((int)v3 + 1)) >> 32) >> 9;
 39 |     int result1 = ((v6 & 0xFFFFDF8C) << 15) ^ v6 ^ ((int)(((v6 & 0xFFFFDF8C) << 15) ^ v6) >> 18);
 40 |     v3 = v5 - 624 * ((v7 >> 31) + v7);
 41 |     return result1;
 42 | }
 43 | char key[0x200];
 44 | char data[0x80];
 45 | char buffer[4096];
 46 | int main(int argc, char** argv)
 47 | {
 48 |     if (argc != 3)
 49 |     {
 50 |         printf("Usage: %s [input] [output]", argv[0]);
 51 |         return -1;
 52 |     }
 53 |     
 54 |     FILE* f = fopen(argv[1], "rb");
 55 |     if (!f)
 56 |     {
 57 |         printf("Failed to open input file");
 58 |         return -1;
 59 |     }
 60 | 
 61 |     int seed = 0;
 62 |     fread(&seed, sizeof(char), 4, f);
 63 |     fread(data, sizeof(char), 0x80, f);
 64 |     init(seed);
 65 | 
 66 |     for (int i = 0; i != 128; i++)
 67 |     {
 68 |         int number = getInt();
 69 |         char* b = (char*)&number;
 70 |         b[0] ^= data[(i * 4) % 0x80];
 71 |         b[1] ^= data[(i * 4 + 7) % 0x80];
 72 |         b[2] ^= data[(i * 4 + 13) % 0x80];
 73 |         b[3] ^= data[(i * 4 + 11) % 0x80];
 74 |         memcpy(&key[i * 4], b, 4);
 75 |     }
 76 | 
 77 |     long long off = getInt();
 78 | 
 79 |     FILE* f2 = fopen(argv[2], "wb");
 80 |     if (!f2)
 81 |     {
 82 |         printf("Failed to open output file");
 83 |         return -1;
 84 |     }
 85 | 
 86 |     while (true)
 87 |     {
 88 |         size_t nbytes = fread(buffer, sizeof(char), 4096, f);
 89 | 
 90 |         for (int i = 0; i != nbytes; i++)
 91 |         {
 92 |             buffer[i] ^= key[(off++) % 0x200];
 93 |         }
 94 | 
 95 |         fwrite(buffer, sizeof(char), nbytes, f2);
 96 | 
 97 |         if (feof(f) || ferror(f))
 98 |             break;
 99 |     }
100 | 
101 |     fclose(f);
102 |     fclose(f2);
103 |     return 0;
104 | }
105 | 


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