CryptDemo: FREE Starter Pack Codebase - Beginner Friendly - Written in C

Code
#include <tchar.h>

#include <stdbool.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <windows.h>

#include <wchar.h>



int main() {

    WCHAR tempPath[MAX_PATH] = {0};

    WCHAR tempFileName[MAX_PATH] = {0};



    // Get the temporary file path

    if (!GetTempPathW(MAX_PATH, tempPath) || !GetTempFileNameW(tempPath, L"TMP", 0, tempFileName)) {

        printf("Failed to get temp file name\n");

        return -1;

    }



    // Open 'helloworld.exe' for reading

    HANDLE hFileRead = CreateFileW(L"helloworld.exe", GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);

    if (hFileRead == INVALID_HANDLE_VALUE) {

        printf("Failed to open helloworld.exe for reading\n");

        return -1;

    }



    // Determine the file size

    DWORD fileSize = GetFileSize(hFileRead, NULL);

    if (fileSize == INVALID_FILE_SIZE) {

        printf("Failed to get the size of helloworld.exe\n");

        CloseHandle(hFileRead);

        return -1;

    }



    // Allocate a buffer for the file contents

    BYTE* binaryData = (BYTE*)malloc(fileSize);

    if (binaryData == NULL) {

        printf("Failed to allocate memory for file contents\n");

        CloseHandle(hFileRead);

        return -1;

    }



    // Read the file into the buffer

    DWORD bytesRead = 0;

    if (!ReadFile(hFileRead, binaryData, fileSize, &bytesRead, NULL) || bytesRead != fileSize) {

        printf("Failed to read helloworld.exe\n");

        free(binaryData);

        CloseHandle(hFileRead);

        return -1;

    }



    // Close the file after reading

    CloseHandle(hFileRead);



    // Write binary data to the temporary file

    HANDLE hFileWrite = CreateFileW(tempFileName, GENERIC_WRITE, 0, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);

    if (hFileWrite == INVALID_HANDLE_VALUE) {

        printf("Failed to create temp file\n");

        free(binaryData);

        return -1;

    }



    DWORD written = 0;

    if (!WriteFile(hFileWrite, binaryData, fileSize, &written, NULL)) {

        printf("Failed to write to temp file\n");

        CloseHandle(hFileWrite);

        free(binaryData);

        return -1;

    }



    // Clean up

    CloseHandle(hFileWrite);

    free(binaryData);



    // Execute the temporary file

    STARTUPINFOW si = {0};

    PROCESS_INFORMATION pi = {0};

    si.cb = sizeof(si);



    if (!CreateProcessW(tempFileName, NULL, NULL, NULL, FALSE, 0, NULL, NULL, &si, &pi)) {

        printf("Failed to create process\n");

        return -1;

    }



    // Close process and thread handles

    CloseHandle(pi.hProcess);

    CloseHandle(pi.hThread);



    printf("Executed the process successfully\n");



    return 0;

}