KgmWasm/kgm.hpp

#include <vector>

std::vector<uint8_t> VprHeader = {
    0x05, 0x28, 0xBC, 0x96, 0xE9, 0xE4, 0x5A, 0x43,
    0x91, 0xAA, 0xBD, 0xD0, 0x7A, 0xF5, 0x36, 0x31 };
std::vector<uint8_t> KgmHeader = {
    0x7C, 0xD5, 0x32, 0xEB, 0x86, 0x02, 0x7F, 0x4B,
    0xA8, 0xAF, 0xA6, 0x8E, 0x0F, 0xFF, 0x99, 0x14 };
std::vector<uint8_t> VprMaskDiff = {
    0x25, 0xDF, 0xE8, 0xA6, 0x75, 0x1E, 0x75, 0x0E,
    0x2F, 0x80, 0xF3, 0x2D, 0xB8, 0xB6, 0xE3, 0x11, 0x00 };

std::vector<uint8_t> MaskV2;

std::vector<uint8_t> table1 = {
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x01, 0x21, 0x01, 0x61, 0x01, 0x21, 0x01, 0xe1, 0x01, 0x21, 0x01, 0x61, 0x01, 0x21, 0x01,
    0xd2, 0x23, 0x02, 0x02, 0x42, 0x42, 0x02, 0x02, 0xc2, 0xc2, 0x02, 0x02, 0x42, 0x42, 0x02, 0x02,
    0xd3, 0xd3, 0x02, 0x03, 0x63, 0x43, 0x63, 0x03, 0xe3, 0xc3, 0xe3, 0x03, 0x63, 0x43, 0x63, 0x03,
    0x94, 0xb4, 0x94, 0x65, 0x04, 0x04, 0x04, 0x04, 0x84, 0x84, 0x84, 0x84, 0x04, 0x04, 0x04, 0x04,
    0x95, 0x95, 0x95, 0x95, 0x04, 0x05, 0x25, 0x05, 0xe5, 0x85, 0xa5, 0x85, 0xe5, 0x05, 0x25, 0x05,
    0xd6, 0xb6, 0x96, 0xb6, 0xd6, 0x27, 0x06, 0x06, 0xc6, 0xc6, 0x86, 0x86, 0xc6, 0xc6, 0x06, 0x06,
    0xd7, 0xd7, 0x97, 0x97, 0xd7, 0xd7, 0x06, 0x07, 0xe7, 0xc7, 0xe7, 0x87, 0xe7, 0xc7, 0xe7, 0x07,
    0x18, 0x38, 0x18, 0x78, 0x18, 0x38, 0x18, 0xe9, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08,
    0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x08, 0x09, 0x29, 0x09, 0x69, 0x09, 0x29, 0x09,
    0xda, 0x3a, 0x1a, 0x3a, 0x5a, 0x3a, 0x1a, 0x3a, 0xda, 0x2b, 0x0a, 0x0a, 0x4a, 0x4a, 0x0a, 0x0a,
    0xdb, 0xdb, 0x1b, 0x1b, 0x5b, 0x5b, 0x1b, 0x1b, 0xdb, 0xdb, 0x0a, 0x0b, 0x6b, 0x4b, 0x6b, 0x0b,
    0x9c, 0xbc, 0x9c, 0x7c, 0x1c, 0x3c, 0x1c, 0x7c, 0x9c, 0xbc, 0x9c, 0x6d, 0x0c, 0x0c, 0x0c, 0x0c,
    0x9d, 0x9d, 0x9d, 0x9d, 0x1d, 0x1d, 0x1d, 0x1d, 0x9d, 0x9d, 0x9d, 0x9d, 0x0c, 0x0d, 0x2d, 0x0d,
    0xde, 0xbe, 0x9e, 0xbe, 0xde, 0x3e, 0x1e, 0x3e, 0xde, 0xbe, 0x9e, 0xbe, 0xde, 0x2f, 0x0e, 0x0e,
    0xdf, 0xdf, 0x9f, 0x9f, 0xdf, 0xdf, 0x1f, 0x1f, 0xdf, 0xdf, 0x9f, 0x9f, 0xdf, 0xdf, 0x0e, 0x0f,
    0x00, 0x20, 0x00, 0x60, 0x00, 0x20, 0x00, 0xe0, 0x00, 0x20, 0x00, 0x60, 0x00, 0x20, 0x00, 0xf1
};

std::vector<uint8_t> table2 = {
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00, 0x01, 0x23, 0x01, 0x67, 0x01, 0x23, 0x01, 0xef, 0x01, 0x23, 0x01, 0x67, 0x01, 0x23, 0x01,
    0xdf, 0x21, 0x02, 0x02, 0x46, 0x46, 0x02, 0x02, 0xce, 0xce, 0x02, 0x02, 0x46, 0x46, 0x02, 0x02,
    0xde, 0xde, 0x02, 0x03, 0x65, 0x47, 0x65, 0x03, 0xed, 0xcf, 0xed, 0x03, 0x65, 0x47, 0x65, 0x03,
    0x9d, 0xbf, 0x9d, 0x63, 0x04, 0x04, 0x04, 0x04, 0x8c, 0x8c, 0x8c, 0x8c, 0x04, 0x04, 0x04, 0x04,
    0x9c, 0x9c, 0x9c, 0x9c, 0x04, 0x05, 0x27, 0x05, 0xeb, 0x8d, 0xaf, 0x8d, 0xeb, 0x05, 0x27, 0x05,
    0xdb, 0xbd, 0x9f, 0xbd, 0xdb, 0x25, 0x06, 0x06, 0xca, 0xca, 0x8e, 0x8e, 0xca, 0xca, 0x06, 0x06,
    0xda, 0xda, 0x9e, 0x9e, 0xda, 0xda, 0x06, 0x07, 0xe9, 0xcb, 0xe9, 0x8f, 0xe9, 0xcb, 0xe9, 0x07,
    0x19, 0x3b, 0x19, 0x7f, 0x19, 0x3b, 0x19, 0xe7, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08,
    0x18, 0x18, 0x18, 0x18, 0x18, 0x18, 0x18, 0x18, 0x08, 0x09, 0x2b, 0x09, 0x6f, 0x09, 0x2b, 0x09,
    0xd7, 0x39, 0x1b, 0x39, 0x5f, 0x39, 0x1b, 0x39, 0xd7, 0x29, 0x0a, 0x0a, 0x4e, 0x4e, 0x0a, 0x0a,
    0xd6, 0xd6, 0x1a, 0x1a, 0x5e, 0x5e, 0x1a, 0x1a, 0xd6, 0xd6, 0x0a, 0x0b, 0x6d, 0x4f, 0x6d, 0x0b,
    0x95, 0xb7, 0x95, 0x7b, 0x1d, 0x3f, 0x1d, 0x7b, 0x95, 0xb7, 0x95, 0x6b, 0x0c, 0x0c, 0x0c, 0x0c,
    0x94, 0x94, 0x94, 0x94, 0x1c, 0x1c, 0x1c, 0x1c, 0x94, 0x94, 0x94, 0x94, 0x0c, 0x0d, 0x2f, 0x0d,
    0xd3, 0xb5, 0x97, 0xb5, 0xd3, 0x3d, 0x1f, 0x3d, 0xd3, 0xb5, 0x97, 0xb5, 0xd3, 0x2d, 0x0e, 0x0e,
    0xd2, 0xd2, 0x96, 0x96, 0xd2, 0xd2, 0x1e, 0x1e, 0xd2, 0xd2, 0x96, 0x96, 0xd2, 0xd2, 0x0e, 0x0f,
    0x00, 0x22, 0x00, 0x66, 0x00, 0x22, 0x00, 0xee, 0x00, 0x22, 0x00, 0x66, 0x00, 0x22, 0x00, 0xfe
};

std::vector<uint8_t> MaskV2PreDef = {
    0xB8, 0xD5, 0x3D, 0xB2, 0xE9, 0xAF, 0x78, 0x8C, 0x83, 0x33, 0x71, 0x51, 0x76, 0xA0, 0xCD, 0x37,
    0x2F, 0x3E, 0x35, 0x8D, 0xA9, 0xBE, 0x98, 0xB7, 0xE7, 0x8C, 0x22, 0xCE, 0x5A, 0x61, 0xDF, 0x68,
    0x69, 0x89, 0xFE, 0xA5, 0xB6, 0xDE, 0xA9, 0x77, 0xFC, 0xC8, 0xBD, 0xBD, 0xE5, 0x6D, 0x3E, 0x5A,
    0x36, 0xEF, 0x69, 0x4E, 0xBE, 0xE1, 0xE9, 0x66, 0x1C, 0xF3, 0xD9, 0x02, 0xB6, 0xF2, 0x12, 0x9B,
    0x44, 0xD0, 0x6F, 0xB9, 0x35, 0x89, 0xB6, 0x46, 0x6D, 0x73, 0x82, 0x06, 0x69, 0xC1, 0xED, 0xD7,
    0x85, 0xC2, 0x30, 0xDF, 0xA2, 0x62, 0xBE, 0x79, 0x2D, 0x62, 0x62, 0x3D, 0x0D, 0x7E, 0xBE, 0x48,
    0x89, 0x23, 0x02, 0xA0, 0xE4, 0xD5, 0x75, 0x51, 0x32, 0x02, 0x53, 0xFD, 0x16, 0x3A, 0x21, 0x3B,
    0x16, 0x0F, 0xC3, 0xB2, 0xBB, 0xB3, 0xE2, 0xBA, 0x3A, 0x3D, 0x13, 0xEC, 0xF6, 0x01, 0x45, 0x84,
    0xA5, 0x70, 0x0F, 0x93, 0x49, 0x0C, 0x64, 0xCD, 0x31, 0xD5, 0xCC, 0x4C, 0x07, 0x01, 0x9E, 0x00,
    0x1A, 0x23, 0x90, 0xBF, 0x88, 0x1E, 0x3B, 0xAB, 0xA6, 0x3E, 0xC4, 0x73, 0x47, 0x10, 0x7E, 0x3B,
    0x5E, 0xBC, 0xE3, 0x00, 0x84, 0xFF, 0x09, 0xD4, 0xE0, 0x89, 0x0F, 0x5B, 0x58, 0x70, 0x4F, 0xFB,
    0x65, 0xD8, 0x5C, 0x53, 0x1B, 0xD3, 0xC8, 0xC6, 0xBF, 0xEF, 0x98, 0xB0, 0x50, 0x4F, 0x0F, 0xEA,
    0xE5, 0x83, 0x58, 0x8C, 0x28, 0x2C, 0x84, 0x67, 0xCD, 0xD0, 0x9E, 0x47, 0xDB, 0x27, 0x50, 0xCA,
    0xF4, 0x63, 0x63, 0xE8, 0x97, 0x7F, 0x1B, 0x4B, 0x0C, 0xC2, 0xC1, 0x21, 0x4C, 0xCC, 0x58, 0xF5,
    0x94, 0x52, 0xA3, 0xF3, 0xD3, 0xE0, 0x68, 0xF4, 0x00, 0x23, 0xF3, 0x5E, 0x0A, 0x7B, 0x93, 0xDD,
    0xAB, 0x12, 0xB2, 0x13, 0xE8, 0x84, 0xD7, 0xA7, 0x9F, 0x0F, 0x32, 0x4C, 0x55, 0x1D, 0x04, 0x36,
    0x52, 0xDC, 0x03, 0xF3, 0xF9, 0x4E, 0x42, 0xE9, 0x3D, 0x61, 0xEF, 0x7C, 0xB6, 0xB3, 0x93, 0x50,
};

uint8_t getMask(size_t pos) {
    size_t offset = pos >> 4;
    uint8_t value = 0;
    while (offset >= 0x11) {
        value ^= table1[offset % 272];
        offset >>= 4;
        value ^= table2[offset % 272];
        offset >>= 4;
    }

    return MaskV2PreDef[pos % 272] ^ value;
}

std::vector<uint8_t> key(17);
bool isVpr = false;

size_t PreDec(uint8_t* fileData, size_t size, bool iV) {
    uint32_t headerLen = *(uint32_t*)(fileData + 0x10);
    memcpy(key.data(), (fileData + 0x1C), 0x10);
    key[16] = 0;
    isVpr = iV;
    return headerLen;
}

void Decrypt(uint8_t* fileData, size_t size, size_t offset) {
    for (size_t i = 0; i < size; ++i) {
        uint8_t med8 = key[(i + offset) % 17] ^ fileData[i];
        med8 ^= (med8 & 0xf) << 4;

        uint8_t msk8 = getMask(i + offset);
        msk8 ^= (msk8 & 0xf) << 4;
        fileData[i] = med8 ^ msk8;

        if (isVpr) {
            fileData[i] ^= VprMaskDiff[(i + offset) % 17];
        }
    }
}