Myujth

with this below code i can store SecretKey into file:

public static SecretKey generateKey() throws NoSuchAlgorithmException 
 // Generate a 256-bit key
 final int outputKeyLength = 256;
 SecureRandom secureRandom = new SecureRandom();
 // Do *not* seed secureRandom! Automatically seeded from system entropy.
 KeyGenerator keyGenerator = KeyGenerator.getInstance("AES");
 keyGenerator.init(outputKeyLength, secureRandom);
 yourKey = keyGenerator.generateKey();
 return yourKey;


yourKey = generateKey();
File file = new File(Environment.getExternalStorageDirectory() + File.separator + "encrypt" + File.separator, "config.xml");

BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(file));
byte filesBytes = yourKey.getEncoded();
bos.write(filesBytes);
bos.flush();
bos.close();

now how can i read this file and pass bytes into SecretKey variable? for example:

File file = new File(Environment.getExternalStorageDirectory() + File.separator + "convert" + File.separator, "config.xml");

BufferedInputStream buf = new BufferedInputStream(
 new FileInputStream(file));


int length = (int) file.length();
byte audio_data = new byte[length];
int bytesRead;
ByteArrayOutputStream output = new ByteArrayOutputStream();
while ((bytesRead = buf.read(audio_data)) != -1) 
 output.write(audio_data, 0, bytesRead);

byte inarry = output.toByteArray();
yourKey=inarry;

problem is yourKey=inarry; and pass bytes into yourKey variable, how can i resolve that?

Even though I never do this myself, if you want to write SecretKey into a file and read it later, you can use ObjectOutputStream and ObjectInputStream.

SecretKey is Serializable, so you can use with those 2 funtions.

write like:

FileOutputStream fout = new FileOutputStream("G:\address.ser");
ObjectOutputStream oos = new ObjectOutputStream(fout);
oos.writeObject(yourKey);
oos.close();
fout.close(); 

read like:

FileInputStream fin = new FileInputStream("G:\address.ser");
ObjectInputStream ois = new ObjectInputStream(fin);
SecretKey yourKey = (SecretKey) ois.readObject();
ois.close();
fin.close(); 

But as I told, you should normally never do it like this. If you want to just store your key, you need to use KeyStore. If you need to save it for sending, you need to save it encrypted. Key is the most important part of a cryptography algorithm, so you should never save it like this in a file.