Question

我正在学习Java安全课程，我们正在学习加密和解密用户提供的信息。

编译代码没有问题，但是在运行代码时，它给出了“线程“ main”中的异常” javax.crypto.IllegalBlockSizeException：解密中的最后一块未完成。”

我相信正在发生的事情是内存地址分别存储在“ saltString ”和“ ciphertextString ”中。这两个变量都可以在“ 加密”方法中找到。

我认为这发生在以下两行中：   “ 字符串ciphertextString = mycipher.doFinal（text）.toString（）；”和“ 字符串saltString = mycipher.doFinal（salt）.toString（）;”

我不确定如何为这些变量分配正确的信息。

感谢您的阅读。

import java.security.*;
import javax.crypto.*;
import javax.crypto.spec.*;
import java.util.*;
import java.util.Scanner;
import java.util.Random;
import java.util.Arrays;

public class PasswordEncryption{

    private static int ITERATIONS = 1000;

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

    Scanner keyboard = new Scanner(System.in);

    //obtain password and text message from the user
    System.out.print("Please enter a password: ");
    char[] password = keyboard.next().toCharArray();
    Scanner keyboard2 = new Scanner(System.in);

    System.out.print("Please enter a text message to encrypt: ");
    String text = keyboard2.nextLine();

    System.out.println();

    String cipherText = encrypt(password, text);
    System.out.println();
    System.out.println("CipherText: " + cipherText);

    System.out.print("Please re-enter your password to decrypt the string: ");
    char[] validPassword = keyboard2.nextLine().toCharArray();
    System.out.println("ValidPassword: " + validPassword);
    String plainText = decrypt(validPassword, cipherText);
    System.out.println(plainText);
    }

private static String encrypt(char[] password, String plainText) throws Exception{

    //begin by creating a random salt of 64 bits(8 bytes)
    byte [] salt = new byte[8];
    Random Random = new Random();
    Random.nextBytes(salt);

    System.out.println("Random bytes: " + Random.nextInt());
    System.out.println("Salt: " + CryptoUtils.toHex(salt));

    //create our key based on password
    PBEKeySpec keySpec = new PBEKeySpec(password);
    SecretKeyFactory keyFactory = 
    SecretKeyFactory.getInstance("PBEWithSHAAnd3KeyTripleDES");
    SecretKey key = keyFactory.generateSecret(keySpec);
    PBEParameterSpec paramSpec = new PBEParameterSpec(salt, ITERATIONS);

    //create a cipher and initialize it for encrypting
    Cipher mycipher = Cipher.getInstance("PBEWithSHAAnd3KeyTripleDES");
    mycipher.init(Cipher.ENCRYPT_MODE, key, paramSpec);

    byte[] text = CryptoUtils.toByteArray(plainText);
    System.out.println("Plaintext: " + plainText);
    System.out.println("PlaintTextArray: " + Arrays.toString(text));

    String ciphertextString = mycipher.doFinal(text).toString();
    String saltString = mycipher.doFinal(salt).toString();

    return saltString + ciphertextString;
}

private static String decrypt(char[] password, String text) throws Exception{

    //being by splitting the text into salt and text Strings

    String salt = text.substring(0,12);
    String ciphertext = text.substring(12,text.length());

    //get the bytes for the salt and ciphertext

    //store salt into saltArray for PBEParameterSpec to take in
    byte[] saltArray = CryptoUtils.toByteArray(salt);
    byte[] ciphertextArray = CryptoUtils.toByteArray(ciphertext);

    System.out.println();
    System.out.println("Salt: " + salt);
    System.out.println("CiperText: " + ciphertext);

    //create our key based on password
    PBEKeySpec keySpec = new PBEKeySpec(password);
    SecretKeyFactory keyFactory = 
    SecretKeyFactory.getInstance("PBEWithSHAAnd3KeyTripleDES");
    SecretKey key = keyFactory.generateSecret(keySpec);
    PBEParameterSpec paramSpec = new PBEParameterSpec(saltArray, ITERATIONS);

    //perform the actual decryption
    Cipher mycipher = Cipher.getInstance("PBEWithSHAAnd3KeyTripleDES");
    mycipher.init(Cipher.DECRYPT_MODE, key, paramSpec);

    byte [] plaintextArray = mycipher.doFinal(ciphertextArray);

    //System.out.println("plaintextArray: " + plaintextArray);

    String plaintext = CryptoUtils.toString(plaintextArray);

    return plaintext;
}
}

变量存储的是地址而不是实际值-安全性新手

0 个答案: