Melindungi File Lisensi Anda - Pembelian

Lisensi Anda disertakan dalam aplikasi yang Anda buat. Hal ini menimbulkan risiko keamanan potensial karena seseorang dapat menemukan lisensi tersebut dan menyalin atau membocorkannya. Menyematkan lisensi sebagai sumber daya internal memberikan perlindungan sampai batas tertentu, namun file asli masih dapat diambil dari paket penyebaran. Halaman ini menyertakan kode untuk membantu Anda melindungi file lisensi dengan lebih aman menggunakan enkripsi. Silakan pilih salah satu contoh di bawah ini:

C#

public void EncryptDecryptLicense()
{
    string encryptedFilePath = MyDir + "EncryptedLicense.txt";

    // Load the contents of the license into a byte array.
    byte[] licBytes = File.ReadAllBytes("YourLicense.lic");
    // Use this key only once for this license file.
    // To protect another file first generate a new key.
    byte[] key = GenerateKey(licBytes.Length);

    // Write the encrypted license to disk.
    File.WriteAllBytes(encryptedFilePath, EncryptDecryptLicense(licBytes, key));

    // Load the encrypted license and decrypt it using the key.
    byte[] decryptedLicense;
    decryptedLicense = EncryptDecryptLicense(File.ReadAllBytes(encryptedFilePath), key);

    // Load the decrypted license into a stream and set the license.
    MemoryStream licenseStream = new MemoryStream(decryptedLicense);

    License license = new License();
    license.SetLicense(licenseStream);
}

/// <summary>
/// A method used for encrypting and decrypting data using XOR.
/// </summary>
public byte[] EncryptDecryptLicense(byte[] licBytes, byte[] key)
{
    byte[] output = new byte[licBytes.Length];

    for (int i = 0; i < licBytes.Length; i++)
        output[i] = Convert.ToByte(licBytes[i] ^ key[i]);

    return output;
}

/// <summary>
/// Generates a random key the same length as the license (a one time pad).
/// </summary>
public byte[] GenerateKey(long size)
{
    RNGCryptoServiceProvider rng = new RNGCryptoServiceProvider();
    byte[] strongBytes = new Byte[size];
    rng.GetBytes(strongBytes);

    return strongBytes;
}

Java

public void encryptDecryptLicense() throws Exception
{
    String encryptedFilePath = getMyDir + "EncryptedLicense.txt";

    // Load the contents of the license into a byte array.
    byte[] licBytes = readAllBytesFromFile("YourLicense.lic");
    // Use this key only once for this license file.
    //To protect another file first generate a new key.
    byte[] key = generateKey(licBytes.Length);

    // Write the encrypted license to disk.
    BufferedOutputStream output = new BufferedOutputStream(new FileOutputStream(
                                           encryptedFilePath));
    output.write(encryptDecryptLicese(licBytes, key));
    output.close();
    
    // Load the encrypted license and decrypt it using the key.
    byte[] decryptedLicense = encryptDecryptLicense(
                      readAllBytesFromFile(encryptedFilePath), key);

    // Load the decrypted license into a stream and set the license.
    ByteArrayInputStream licenseStream = new ByteArrayInputStream(decryptedLicense);

    License license = new License();
    license.SetLicense(licenseStream);
}

// A method used for encrypting and decrypting data using XOR.
public byte[] encryptDecryptLicense(byte[] licBytes, byte[] key)
{
    byte[] output = new byte[licBytes.Length];

    for (int i = 0; i < licBytes.Length; i++)
        output[i] = (byte)(licBytes[i] ^ key[i]);

    return output;
}

// Generates a random key the same length as the license (a one time pad).
public byte[] generateKey(int size)
{
    SecureRandom rng = new SecureRandom();
    byte[] strongBytes = new byte[size];
    rng.nextBytes(strongBytes);

    return strongBytes;
}

public byte[] readAllBytesFromFile(String filePath) Throws IOException
{
    int pos;
    InputStream inputStream = new FileInputStream(filePath);
    ByteArrayOutputStream bos = new ByteArrayOutputStream();
    while ((pos = inputStream.Read() != -1)
        bos.write(pos);
        
    inputStream.close();
                    
    return bos.toByteArray();
}

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