cloud-dark/pdf-flag-validator

PDF-Flag-Validator

PDF-Flag-Validator is a simple yet effective tool for adding a custom flag to a PDF file and validating the file's integrity based on the presence of that flag. By utilizing the fs module in Node.js, this tool helps ensure the integrity of your PDF files with ease.

Features

• Add Flag: Insert a custom flag into a PDF file for identification and validation purposes.
• File Validation: Check if a PDF file has been tampered with by verifying the presence of the flag.
• Easy to Use: Simple implementation with just a few lines of code.
• Node.js Based: Leverages the power of the fs module for fast and reliable file operations.

Installation

1. Clone this repository:

   git clone https://github.com/Cloud-Dark/PDF-Flag-Validator.git

2. Navigate to the project directory:

   cd PDF-Flag-Validator

3. Install the dependencies:

   npm install

Usage

1. Ensure you have a source PDF file (sample.pdf).
2. Run the following script to add a flag and check the file's validity:

   node index.js

Example Code

// Import the 'fs' module to handle file system operations
const fs = require('fs');

// Define the source PDF file
const sourceFile = 'sample.pdf';
// Define the destination PDF file
const destinationFile = 'sample.enc.pdf';

// Define the flag to be added to the PDF
const flag = 'flag=%fl4g_h3r3%';

// Read the contents of the source file
fs.readFile(sourceFile, (err, data) => {
    // Handle any errors that occur during file reading
    if (err) {
        return console.log(err);
    }

    // Append the flag to the file data
    const modifiedData = Buffer.concat([data, Buffer.from(flag)]);

    // Write the modified data to the destination file
    fs.writeFile(destinationFile, modifiedData, (err) => {
        // Handle any errors that occur during file writing
        if (err) {
            return console.log(err);
        }
        console.log('File created and flag appended!');

        // Check the validity of the new file
        checkValidFile(destinationFile);
    });
});

// Function to check the validity of the file by verifying the presence of the flag
function checkValidFile(filePath) {
    // Read the contents of the file to be checked
    fs.readFile(filePath, (err, data) => {
        // Handle any errors that occur during file reading
        if (err) {
            return console.log(err);
        }

        // Check if the flag is present in the file data
        if (data.includes(Buffer.from(flag))) {
            console.log('file valid');
        } else {
            console.log('file not valid');
        }
    });
}

Contributing

We welcome contributions from the community! If you have ideas or improvements, please create a pull request or open an issue in this repository.

License

This project is licensed under the MIT License.

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