2012-07-10 89 views
0

在解密類,我不能得到它正確解密。我已經在解密類中驗證過,我的salt和密文在將它們轉換回字節之前仍然保留相同的值。3des Java加密和解密與鹽和迭代

程序本身並沒有給出錯誤,但是當我編譯時,我會加密,將它保存到字符串encryptPhrase中,然後在解密方法中解密它,我似乎無法正確解密它。我在註釋中標記了問題所在,並給出了一個不良緩衝的異常,但是沒有填充?

奇怪的是...如果我拿出解密方法中的所有內容並返回只是encryptPhrase,它實際上會返回正確的純文本。

任何幫助,將不勝感激。謝謝! :)

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 = "abcdef"; 

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); 
} 
} 

回答

1

又一個字節和字符混淆。可能已經猜到了。請查閱base 64編碼,看看它爲什麼存在。然後注意執行Object.toString()和查找字符編碼(不要在隨機字節上使用new String(byte[]))。