復号化クラスでは、正しく復号化できません。復号化クラスで、ソルトと暗号文がバイトに戻す前に同じ値を保持していることを確認しました。
プログラム自体はエラーを出しませんが、コンパイル時に暗号化して文字列encryptPhraseに保存し、復号化メソッドで復号化しますが、正しく復号化できないようです。問題があり、バッドパディングの例外を与えるコメントにマークを付けましたが、パディングはありませんか?
奇妙なことに...復号化メソッドのすべてを取り出してencryptPhraseだけを返すと、実際には正しいプレーンテキストが返されます。
どんな助けでも大歓迎です。ありがとう！:)
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);
}
}