CODEWITHSUNDEEP
javaencryptionbase64secret-key
Mandar Bhamare
Mandar Bhamare

Reputation: 27

Regeneration of SecretKey results in different key in java

I am trying to create an Encryption Program. However, The problem is when I am trying to Regenerate the SecretKey, I get different key which is not the same as the encryption key.

Here is my code snippet which I am using for testing purpose.`

import com.sun.org.apache.xerces.internal.impl.dv.util.Base64;
import java.util.*;
import java.io.*;
import java.nio.charset.StandardCharsets;
import javax.crypto.*;
import javax.crypto.spec.SecretKeySpec;

class Test
{
    static void My_Get_Key() throws Exception
    {
    String temp;
    File f=new File("/home/mandar/Desktop/key.txt");
    Scanner sc=new Scanner(f);
    temp=sc.nextLine();

    byte[] sk=Base64.decode(temp);
    //byte[] sk=temp.getBytes();
    //byte[] sk=temp.getBytes(StandardCharsets.ISO_8859_1);
     SecretKey OriginalKey=new SecretKeySpec(sk,0,sk.length,"AES");
     System.out.println("Decrypt Key is "+OriginalKey.toString());
     //return OriginalKey;

    }
 static void My_Key_Generate() throws Exception
 {
KeyGenerator key=KeyGenerator.getInstance("AES");
key.init(128);
SecretKey sk=key.generateKey();
System.out.println("Encrypt Key is "+sk.toString());
BufferedWriter wt = new BufferedWriter(new FileWriter("/home/mandar/Desktop/key.txt"));
String KeyString =sk.toString();
    byte[] bytekey= KeyString.getBytes();
    String WriteKey= Base64.encode(bytekey);
wt.write(sk.toString()); 
wt.flush();
wt.close();
//return sk;

 }
  public static void main(String[] args) throws Exception
  {
    My_Key_Generate();
    My_Get_Key();
  }
 }

please Help.

PS: I am trying to store the generated key by converting it into string and writing it into a file and using the same file to retrieve the string and regenerate the key again.

Upvotes: 2

Views: 911

Answers (1)

eugenioy
eugenioy

Reputation: 12393

The problem is that "sk.toString()" does not provide the contents of the key.

You need to call "sk.getEncoded()". Please note that it will return a byte array, not an String.

Write the contents of that byte array to the file and read it back.

Try with this modified code that uses "getEncoded()":

import java.util.*;
import java.nio.file.Files;
import java.nio.file.Paths;

import javax.crypto.*;
import javax.crypto.spec.SecretKeySpec;

class Test {

    static void My_Get_Key() throws Exception {
        byte[] sk = Files.readAllBytes(Paths.get("/home/mandar/Desktop/key.txt"));
        SecretKey OriginalKey = new SecretKeySpec(sk, 0, sk.length, "AES");
        System.out.println("Decrypt Key is " + Arrays.toString(OriginalKey.getEncoded()));
    }

    static void My_Key_Generate() throws Exception {
        KeyGenerator key = KeyGenerator.getInstance("AES");
        key.init(128);
        SecretKey sk = key.generateKey();
        System.out.println("Encrypt Key is " + Arrays.toString(sk.getEncoded()));
        Files.write(Paths.get("/home/mandar/Desktop/key.txt"), sk.getEncoded());
    }

    public static void main(String[] args) throws Exception {
        My_Key_Generate();
        My_Get_Key();
    }

}

Upvotes: 2

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