In the decrypt class, I cant get it to correctly decrypt. I've verified in the decrypt class that my salt and my ciphertext still carries the same values before I convert them back to bytes.
The program itself doesn't given an error however when I compile, I'll encrypt, save it to the string encryptPhrase and then decrypt it in the decrypt method and I cant seem to get it to decrypt properly. I've marked in comments where the issue is and gives a badpadding exception, however there is no padding?
The odd thing is... if i take out everything in the decrypt method and return just encryptPhrase, it actually returns the correct plain text.
Any help would be appreciated. Thanks! :)
import java.security.*;
import javax.crypto.*;
import javax.crypto.spec.*;
import java.util.*;
public class PasswordEncryption {
private static int ITERATIONS = 1000;
private static String saltString;
private static String ciphertextString;
private static String encryptPhrase;
private static void usage(){
System.err.println("Usage: java PBE -e|-d password text");
System.exit(1);
}
public static void main(String[] args) throws Exception{
scan = new Scanner(System.in);
System.out.println("Please enter plain text: ");
String text = scan.nextLine();
System.out.println("Please enter password to encrypt plain text: ");
char [] pw = scan.nextLine().toCharArray();
int option=3;
while (option!=0){
System.out.println("Are we encrypting(1) or decrypting(2) or Exit(0)? " );
option = scan.nextInt();
String output="exiting program";
if (option == 1)
output = encrypt(pw, text);
else if (option ==2)
output = decrypt(pw,text);
System.out.println("Output: " +output);
}
}
private static Scanner scan;
private static String encrypt(char[] password, String plaintext) throws Exception {
//create random salt
byte[] salt = new byte[8];
SecureRandom random = new SecureRandom();
random.nextBytes(salt);
//create key based on password
int iterationCount = ITERATIONS;
PBEKeySpec pbeSpec = new PBEKeySpec(password, salt, iterationCount);
SecretKeyFactory keyFact = SecretKeyFactory.getInstance("PBEWithSHAAnd3KeyTripleDES");
//create a cipher
Cipher myCipher = Cipher.getInstance("PBEWithSHAAnd3KeyTripleDES");
Key encryptKey = keyFact.generateSecret(pbeSpec);
myCipher.init(Cipher.ENCRYPT_MODE, encryptKey);
byte[] cipherText = myCipher.doFinal();
System.out.println("Encrypted Text: " +toString(cipherText));
//produce salt to string
saltString = salt.toString();
System.out.println("SALT: " +saltString);
//produce cipher text to string
ciphertextString = toString(cipherText);
//stores salt and cipher string in encryptPhrase
encryptPhrase = saltString+ciphertextString;
return saltString+ciphertextString;
}
public static String decrypt(char[] password, String encryptPhrase) throws Exception{
//split the encryption data into salt and ciphertext
//System.out.println("encrypt Phrase: " +encryptPhrase);
//convert salt into bytearray
byte[] bsalt = toByteArray(saltString);
//convert ciphertext into bytearray
byte[] bciphert= toByteArray(ciphertextString);
//produce cipher
/////////////////////////////////////////////////////////////////////
int iterationCount = ITERATIONS;
PBEKeySpec pbeSpec = new PBEKeySpec(password, bsalt, iterationCount);
//use SHA and 3DES
//create the key
SecretKeyFactory keyFact = SecretKeyFactory.getInstance("PBEWithSHAAnd3KeyTripleDES");
Cipher cDec = Cipher.getInstance("PBEWithSHAAnd3KeyTripleDES");
Key sKey = keyFact.generateSecret(pbeSpec);
//perform decryption
cDec.init(cDec.DECRYPT_MODE,sKey);
byte [] plainTextb = cDec.doFinal(bciphert); //gives me an error here. Says BadPaddingException: pad block corrupted?
String plainText = toString(plainTextb);
return plainText;
//return encryptPhrase;
}
/**
* Convert a byte array of 8 bit characters into a String.
*
*@param bytes the array containing the characters
* @param length the number of bytes to process
* @return a String representation of bytes
*/
public static String toString(byte[] bytes, int length)
{
char[] chars = new char[length];
for (int i = 0; i != chars.length; i++)
{
chars[i] = (char)(bytes[i] & 0xff);
}
return new String(chars);
}
/**
* Convert a byte array of 8 bit characters into a String.
*
* @param bytes the array containing the characters
* @return a String representation of bytes
*/
public static String toString( byte[] bytes)
{
return toString(bytes, bytes.length);
}
/**
* Convert the passed in String to a byte array by
* taking the bottom 8 bits of each character it contains.
*
* @param string the string to be converted
* @return a byte array representation
*/
public static byte[] toByteArray(String string)
{
byte[] bytes = new byte[string.length()];
char[] chars = string.toCharArray();
for (int i = 0; i != chars.length; i++)
{
bytes[i] = (byte)chars[i];
}
return bytes;
}
private static String digits = "0123456789abcdef";
public static String toHex(byte[] data, int length)
{
StringBuffer buf = new StringBuffer();
for (int i=0; i!= length; i++)
{
int v = data[i] & 0xff;
buf.append(digits.charAt(v >>4));
buf.append(digits.charAt(v & 0xf));
}
return buf.toString();
}
/**
* Return the passed in byte array as a hex string.
*
* @param data the bytes to be converted.
* @return a hex representation of data.
*/
public static String toHex(byte[] data)
{
return toHex(data, data.length);
}
}
