AES with 256 bit key size and apply password
I wan to encrypt/decrypt large data with AES with 256 bit key size. I want to ecrypt/decrypt data with a password. I dont know how to add this password. Anyone please help me as it is urgent.import java.security.*;
import javax.crypto.*;
import javax.crypto.spec.*;
import java.io.*;
/**
* This program generates a AES key, retrieves its raw bytes, and
* then reinstantiates a AES key from the key bytes.
* The reinstantiated key is used to initialize a AES cipher for
* encryption and decryption.
*/
publicclass JavaAES256
{
publicstaticvoid main(String[] args)throws Exception
{
String message="This is just an example";
// Get the KeyGenerator
KeyGenerator kgen = KeyGenerator.getInstance("AES");
kgen.init(256);// 192 and 256 bits may not be available
// Generate the secret key specs.
SecretKey skey = kgen.generateKey();
byte[] raw = skey.getEncoded();
SecretKeySpec skeySpec =new SecretKeySpec(raw,"AES");
// Instantiate the cipher
Cipher cipher = Cipher.getInstance("AES");
cipher.init(Cipher.ENCRYPT_MODE, skeySpec);
byte[] encrypted = cipher.doFinal("This is just an example".getBytes());
System.out.println("encrypted string: " + asHex(encrypted));
cipher.init(Cipher.DECRYPT_MODE, skeySpec);
byte[] original = cipher.doFinal(encrypted);
String originalString =new String(original);
System.out.println("Original string: " +
originalString +" " + asHex(original));
}
/**
* Turns array of bytes into string
*
* @param bufArray of bytes to convert to hex string
* @returnGenerated hex string
*/
publicstatic String asHex (byte buf[])
{
StringBuffer strbuf =new StringBuffer(buf.length * 2);
int i;
for (i = 0; i < buf.length; i++)
{
if (((int) buf[i] & 0xff) < 0x10)
strbuf.append("0");
strbuf.append(Long.toString((int) buf[i] & 0xff, 16));
}
return strbuf.toString();
}
}
