-
-
Save coldnegative/c7420b26f7a809eb880898fde2aec35e to your computer and use it in GitHub Desktop.
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| #include <iostream> | |
| #include <fstream> | |
| #include <memory> | |
| #include <string> | |
| #include <algorithm> | |
| void process_crypt_table(unsigned *crypt_table) | |
| { | |
| for (auto i = 0; i < 227; i++) | |
| { | |
| crypt_table[i] = | |
| crypt_table[i + 397] ^ | |
| ((crypt_table[i + 1] & 1) != 0 ? 0x9908B0DF : 0) ^ | |
| ((crypt_table[i] ^ (crypt_table[i + 1] ^ crypt_table[i]) & 0x7FFFFFFE) >> 1); | |
| } | |
| for (auto i = 0; i < 396; i++) | |
| { | |
| crypt_table[i + 227] = | |
| crypt_table[i] ^ | |
| ((crypt_table[i + 228] & 1) != 0 ? 0x9908B0DF : 0) ^ | |
| ((crypt_table[i + 227] ^ (crypt_table[i + 228] ^ crypt_table[i + 227]) & 0x7FFFFFFE) >> 1); | |
| } | |
| crypt_table[623] = | |
| crypt_table[396] ^ | |
| ((crypt_table[0] & 1) != 0 ? 0x9908B0DF : 0) ^ | |
| ((crypt_table[623] ^ (crypt_table[0] ^ crypt_table[623]) & 0x7FFFFFFE) >> 1); | |
| } | |
| void decrypt(const char *name) | |
| { | |
| std::ifstream in(name, std::ios::binary); | |
| if (!in) | |
| { | |
| std::cerr << "Couldn't open " << name << std::endl; | |
| return; | |
| } | |
| auto cppname = std::string(name); | |
| std::ofstream out(cppname + ".decrypted", std::ios::binary); | |
| // Remove path | |
| const auto slash_it = std::find(cppname.rbegin(), cppname.rend(), '/'); | |
| if (slash_it != cppname.rend()) | |
| cppname.erase(cppname.begin(), slash_it.base()); | |
| const auto bslash_it = std::find(cppname.rbegin(), cppname.rend(), '\\'); | |
| if (bslash_it != cppname.rend()) | |
| cppname.erase(cppname.begin(), bslash_it.base()); | |
| // Uppercase | |
| std::transform(cppname.begin(), cppname.end(), cppname.begin(), toupper); | |
| // Use the uppercase filename to seed the crypto algorithm | |
| auto crypt_seed = 0; | |
| for (auto &c : cppname) | |
| crypt_seed = c + 137 * crypt_seed; | |
| in.seekg(0, std::ios::end); | |
| const auto size = (int)(in.tellg()); | |
| in.seekg(0); | |
| auto buf = std::make_unique<unsigned[]>(size / 4); | |
| in.read((char*)(buf.get()), size); | |
| unsigned crypt_table[624]; | |
| crypt_table[0] = crypt_seed; | |
| for (auto i = 1; i < 624; i++) | |
| { | |
| const auto last = crypt_table[i - 1]; | |
| crypt_table[i] = i + 0x6C078965 * (last ^ (last >> 30)); | |
| } | |
| auto last_out = 0x43415046u; | |
| for (auto i = 0; i < size / 4; i++) | |
| { | |
| if (i % 624 == 0) | |
| process_crypt_table(crypt_table); | |
| const auto entry = crypt_table[i % 624]; | |
| const auto key = | |
| (((((((entry >> 11) ^ entry) & 0xFF3A58AD) << 7) ^ (entry >> 11) ^ entry) & 0xFFFFDF8C) << 15) ^ | |
| ((((entry >> 11) ^ entry) & 0xFF3A58AD) << 7) ^ | |
| (entry >> 11) ^ | |
| entry; | |
| last_out ^= buf[i] ^ (key ^ (key >> 18)); | |
| out.write((char*)(&last_out), 4); | |
| } | |
| } | |
| int main(const int argc, const char *argv[]) | |
| { | |
| if (argc <= 1) | |
| { | |
| std::cerr << "ggxrd_decrypter <filename1> <filename2> etc" << std::endl; | |
| return EXIT_FAILURE; | |
| } | |
| for (auto i = 1; i < argc; i++) | |
| decrypt(argv[i]); | |
| return 0; | |
| } |
Author
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
0x72642A6Fu