r4/gd-gamesave-cryptor
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Add library functionality for level data

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This commit is contained in:
xypwn 2020-05-05 13:40:52 +02:00
parent 9bbd5cf16a
commit 7586e8d5ab
2 changed files with 39 additions and 28 deletions
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51
GDGameSave.hpp
View File

@ -8,8 +8,7 @@ constexpr int CHUNK = 16384;
constexpr int WINDOW_BITS = 15;
//Returns true if it was able to open the given file for reading
bool IsFile(const std::string& filename)
{
bool IsFile(const std::string& filename) {
std::ifstream file(filename);
const bool ret = file.good();
file.close();
@ -44,8 +43,7 @@ void Xor_Str(std::string& str, unsigned char key) {
}
}
std::string GZipDecompress(const std::string& in)
{
std::string GZipDecompress(const std::string& in) {
//Initialize all members of strm to be 0
z_stream strm = {};
//Output buffer
@ -82,8 +80,7 @@ std::string GZipDecompress(const std::string& in)
return final_output;
}
std::string GZipCompress(const std::string& in)
{
std::string GZipCompress(const std::string& in) {
//Initialize all members of strm to be 0
z_stream strm = {};
//Output buffer
@ -114,11 +111,17 @@ std::string GZipCompress(const std::string& in)
return final_output;
}
std::string Decrypt(const std::string& filename) {
//load file
std::string ret = FileToStr(filename);
//Xor with value 11
Xor_Str(ret, 11);
/** @brief Decrypt GD save files or level data *
* @param in_data encrypted input data *
* @param xor11 whether or not the data should be xored with 11; *
* select true for gamesave or false for level data *
* @retval decrypted data **/
std::string Decrypt(const std::string& in_data, bool xor11) {
//Retun value
std::string ret = in_data;
//Xor with value 11 if nescessary
if(xor11)
Xor_Str(ret, 11);
//replace - with + and _ with /
for (auto& i : ret) {
if (i == '-')
@ -134,20 +137,23 @@ std::string Decrypt(const std::string& filename) {
return ret;
}
std::string Encrypt(const std::string& filename) {
//load file
std::string data = FileToStr(filename);
//Calculate crc32 checksum
uLong crc = crc32(0L, Z_NULL, 0);
uint32_t crc32_sum = crc32(crc, (Bytef*)data.data(), data.size());
uint32_t dataSize = data.size();
/** @brief Encrypt GD save files or level data *
* @param in_data decrypted input data *
* @param xor11 whether or not the data should be xored with 11; *
* select true for gamesave or false for level data *
* @retval encrypted data **/
std::string Encrypt(const std::string& in_data, bool xor11) {
//Calculate crc32 checksum and size
const uLong crc = crc32(0L, Z_NULL, 0);
const uint32_t crc32_sum = crc32(crc, (Bytef*)in_data.data(), in_data.size());
const uint32_t dataSize = in_data.size();
//Compress with GZip
std::string ret = GZipCompress(data);
std::string ret = GZipCompress(in_data);
//Remove first 2 and last 4 chars of string
ret = ret.substr(2, ret.size() - 4 - 2);
//Add header, checksum and size
char header[10] = {'\x1f', '\x8b', '\x08', '\x00', '\x00', '\x00', '\x00', '\x00', '\x00', '\x0b'};
ret = std::string(header, sizeof(header)) +
ret = std::string(header, sizeof(header)) +
ret +
std::string((const char*)&crc32_sum, sizeof(crc32_sum)) + //Use raw binary data
std::string((const char*)&dataSize, sizeof(dataSize)); //Use raw binary data
@ -160,8 +166,9 @@ std::string Encrypt(const std::string& filename) {
if (i == '/')
i = '_';
}
//Xor with value 11
Xor_Str(ret, 11);
//Xor with value 11 if nescessary
if(xor11)
Xor_Str(ret, 11);
//Return
return ret;
}

16
Main.cpp
View File

@ -20,24 +20,27 @@ const std::string commands = R"(Commands:
3: Encrypt and save to GD folder
0: Quit)";
enum class Command
{
enum class Command {
Decrypt,
Encrypt
};
bool ExecCommand(Command cmd, const std::string& in_filename, const std::string& out_filename)
{
bool ExecCommand(Command cmd, const std::string& in_filename, const std::string& out_filename) {
//Check if input file is valid
if(!IsFile(in_filename))
{
std::cerr << "ERROR: Could not open file " << in_filename << " for reading" << std::endl;
return false;
}
//Read file data into a string
std::string data = FileToStr(in_filename);
switch(cmd)
{
case Command::Decrypt:
std::cout << "Decrypting " << in_filename << "..." << std::endl;
if(!StrToFile(out_filename, Decrypt(in_filename)))
// Attempt to decrypt data and save it in the given output file
if(!StrToFile(out_filename, Decrypt(data, true)))
{
std::cerr << "ERROR: Could not open file " << out_filename << " for writing" << std::endl;
return false;
@ -45,7 +48,8 @@ bool ExecCommand(Command cmd, const std::string& in_filename, const std::string&
break;
case Command::Encrypt:
std::cout << "Encrypting " << in_filename << "..." << std::endl;
if(!StrToFile(out_filename, Encrypt(in_filename)))
// Attempt to encrypt data and save it in the given output file
if(!StrToFile(out_filename, Encrypt(data, true)))
{
std::cerr << "ERROR: Could not open file " << out_filename << " for writing" << std::endl;
return false;