Exception java.security.InvalidKeyException: Invalid key length: 24 bytes using DESede

Question

I know that this question is often asked but I have checked everything I found in Stack Overflow and did not find the solution to my problem.
i am using DESede for encryption and decryption and taking external 24 byte key input. but getting exception.

here is my code:

    import java.security.InvalidKeyException;
    import java.security.NoSuchAlgorithmException;
    import java.security.spec.InvalidKeySpecException;

    import javax.crypto.BadPaddingException;
    import javax.crypto.Cipher;
    import javax.crypto.IllegalBlockSizeException;
    import javax.crypto.SecretKeyFactory;
    import javax.crypto.NoSuchPaddingException;
    import javax.crypto.SecretKey;
    import javax.crypto.spec.DESedeKeySpec;
    import javax.xml.bind.DatatypeConverter;

    public class DESede {

     private static Cipher encryptCipher;
     private static Cipher decryptCipher;

     public static void main(String[] args) throws InvalidKeySpecException {
      try {


       String desKey = "0123456789abcdef0123456789abcdef0123456789abcdef"; // value from user
       byte[] keyBytes = DatatypeConverter.parseHexBinary(desKey);
       System.out.println((int)keyBytes.length);

       SecretKeyFactory factory = SecretKeyFactory.getInstance("DESede");
       SecretKey key = factory.generateSecret(new DESedeKeySpec(keyBytes));

       encryptCipher = Cipher.getInstance("DES/ECB/PKCS5Padding");
       encryptCipher.init(Cipher.ENCRYPT_MODE, key); //throwing Exception
       byte[] encryptedData = encryptData("Confidential data");

       decryptCipher = Cipher.getInstance("DES/ECB/PKCS5Padding");
       decryptCipher.init(Cipher.DECRYPT_MODE, key);
       decryptData(encryptedData);

      } catch (NoSuchAlgorithmException e) {
       e.printStackTrace();
      } catch (NoSuchPaddingException e) {
       e.printStackTrace();
      } catch (InvalidKeyException e) {
       e.printStackTrace();
      } catch (IllegalBlockSizeException e) {
       e.printStackTrace();
      } catch (BadPaddingException e) {
       e.printStackTrace();
      }

     }

//method for encryption

     private static byte[] encryptData(String data)
       throws IllegalBlockSizeException, BadPaddingException {
      System.out.println("Data Before Encryption :" + data);
      byte[] dataToEncrypt = data.getBytes();
      byte[] encryptedData = encryptCipher.doFinal(dataToEncrypt);
      System.out.println("Encryted Data: " + encryptedData);

      return encryptedData;
     }

//method for decryption

     private static void decryptData(byte[] data)
       throws IllegalBlockSizeException, BadPaddingException {
      byte[] textDecrypted = decryptCipher.doFinal(data);
      System.out.println("Decryted Data: " + new String(textDecrypted));
     }
    }

i am getting exception at the line: java.security.InvalidKeyException: Invalid key length: 24 bytes

encryptCipher.init(Cipher.ENCRYPT_MODE, key);

any one have any idea why this is happening?

Note : With JDK-8 the error is : java.security.InvalidKeyException: Wrong algorithm: DES required. With JDK-6, error is as noted above : java.security.InvalidKeyException: Invalid key length: 24 bytes. Will update if I identify for JDK-7. — Ravindra HV
– Ravindra HV, Commented Apr 27, 2018 at 22:24

lakshman · Accepted Answer · 2014-04-09 05:48:10Z

1

There is two mistakes you have done in your code

you use DESede to create the secret key factory in this line

 SecretKeyFactory factory = SecretKeyFactory.getInstance("DESede");

but you use the DES to get the Cipher object. you have to use DESede instead

so use this line

encryptCipher = Cipher.getInstance("DESede/CBC/PKCS5Padding");

instead of this line

encryptCipher = Cipher.getInstance("DES/ECB/PKCS5Padding");

use the same algorithm to get decripting cipher

and another one is use a AlgorithmParameterSpec to init the decrypting cipher.

byte iv[] = encryptCipher.getIV(); 
IvParameterSpec dps = new IvParameterSpec(iv);
decryptCipher.init(Cipher.DECRYPT_MODE, key, dps);

you can use above code to apply the AlgorithmParameterSpec to the initialization of cipher

edited Apr 9, 2014 at 5:48

answered Apr 9, 2014 at 4:46

lakshman

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3 Comments

nitinkt Over a year ago

i have done ur changes, now the same exception is thrown in line decryptCipher.init(Cipher.DECRYPT_MODE, key, dps);

lakshman Over a year ago

did you change this line decryptCipher = Cipher.getInstance("DES/ECB/PKCS5Padding"); to this line decryptCipher = Cipher.getInstance("DESede/CBC/PKCS5Padding");?

nitinkt Over a year ago

this line byte iv[] = encryptCipher.getIV(); is throwing Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException when decrypting the string from swing application, which is encrypted from jsp module with same algorithm. and vice versa. but if use swing to swing or jsp to jsp, then working. other AES,DES are working when swing to jsp or jsp to swing. but this is not. any idea why this is happening? thanks for your time..

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