Question

喂，

我用Blowfish用Java加密和解密。

加密工作正常，但解密失败。

这是我的解密Java代码：

String encryptedString = … ;
String decryptedString = null;
SecretKeySpec key = new SecretKeySpec(myKey.getBytes(), "Blowfish");
Cipher cipher;
try {
    cipher = Cipher.getInstance("Blowfish");
    cipher.init(Cipher.DECRYPT_MODE, key);
    byte[] decrypted = cipher.doFinal(encryptedString.getBytes());
    decryptedString = new String(decrypted, Charset.forName("UTF-8"));
} [ catch Exceptions … ]

我得到一个例外：

Exception. javax.crypto.IllegalBlockSizeException: Input length must be multiple of 8 when decrypting with padded cipher

你能告诉我如何让它干活吗？谢谢。

我给出的输入来自我的加密Java代码，+ Base64中的+编码，我在将它解释为解密操作之前就从Base64解码。

Answer 1

将字节转换为十六进制和返回是很棘手的。这应该可以解决您的问题。（您需要修复encryptedString的字符串表示形式）

<强>输出：

StackOverflow 537461636B4F766572666C6F77 [83, 116, 97, 99, 107, 79, 118, 101, 114, 102, 108, 111, 119]
J~3¹ÙÂÖ"¢ª„¨u 194A7E33B9060CD9C2D622A2AA84A875 [25, 74, 126, 51, -71, 6, 12, -39, -62, -42, 34, -94, -86, -124, -88, 117]
StackOverflow 537461636B4F766572666C6F77 [83, 116, 97, 99, 107, 79, 118, 101, 114, 102, 108, 111, 119]

<强>代码：

import java.util.Arrays;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;

public class Main {

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

    KeyGenerator keygenerator = KeyGenerator.getInstance("Blowfish");
    SecretKey secretkey = keygenerator.generateKey();

    String plaintextString = "StackOverflow";
    System.out.println(plaintextString + " " + bytesToHex(plaintextString.getBytes()) + " " + Arrays.toString(plaintextString.getBytes()));

    SecretKeySpec key = new SecretKeySpec(secretkey.getEncoded(), "Blowfish");
    Cipher cipher = Cipher.getInstance("Blowfish");

    cipher.init(Cipher.ENCRYPT_MODE, key);
    byte[] encrypted = cipher.doFinal(plaintextString.getBytes());
    String encryptedString = bytesToHex(encrypted);
    System.out.println(new String(encrypted) + " " + encryptedString + " " + Arrays.toString(encrypted));

    cipher.init(Cipher.DECRYPT_MODE, key);
    byte[] decrypted = cipher.doFinal(hexToBytes(encryptedString));
    String decryptedString = bytesToHex(decrypted);
    System.out.println(new String(decrypted) + " " + decryptedString + " " + Arrays.toString(decrypted));

  }

  public static byte[] hexToBytes(String str) {
    if (str == null) {
      return null;
    } else if (str.length() < 2) {
      return null;
    } else {
      int len = str.length() / 2;
      byte[] buffer = new byte[len];
      for (int i = 0; i < len; i++) {
        buffer[i] = (byte) Integer.parseInt(str.substring(i * 2, i * 2 + 2), 16);
      }
      return buffer;
    }

  }

  public static String bytesToHex(byte[] data) {
    if (data == null) {
      return null;
    } else {
      int len = data.length;
      String str = "";
      for (int i = 0; i < len; i++) {
        if ((data[i] & 0xFF) < 16)
          str = str + "0" + java.lang.Integer.toHexString(data[i] & 0xFF);
        else
          str = str + java.lang.Integer.toHexString(data[i] & 0xFF);
      }
      return str.toUpperCase();
    }
  }
}

Answer 2

您的myKey变量长度必须是8的倍数

Answer 3

String encryptedString = … ;  
String decryptedString = null;
SecretKeySpec key = new SecretKeySpec(myKey.getBytes(), "Blowfish");
private static byte[] linebreak = {}; // Remove Base64 encoder default linebreak
private static Base64 coder;
Cipher cipher;
try {
    coder = new Base64(32, linebreak, true);
    cipher = Cipher.getInstance("Blowfish");
    cipher.init(Cipher.DECRYPT_MODE, key);
    byte[] decrypted = cipher.doFinal(encryptedString.getBytes());
    decryptedString = new String(coder.encode(decrypted));
} [ catch Exceptions … ]

您可以使用Base64类来解决此问题。

Answer 4

现在我有了解决方案！

首先，Unicode存在一些问题，所以我把ISO-8859-1放在了各处。 Including in the Base64 encoding and decoding.

然后，我和变种一起玩了。

这是我的Java代码，适用于Blowfish解密：

String encryptedString = … ;
String decryptedString = null;
SecretKeySpec key = new SecretKeySpec(myKey.getBytes(CHARSET_ISO_8859_1), "Blowfish");
Cipher cipher;
try {
    cipher = Cipher.getInstance("Blowfish/ECB/PKCS5Padding");
    cipher.init(Cipher.DECRYPT_MODE, key);
    byte[] decrypted = cipher.doFinal(encryptedString.getBytes(CHARSET_ISO_8859_1));
    decryptedString = new String(decrypted, CHARSET_ISO_8859_1);
} [ catch Exceptions … ]

请注意，我已将"Blowfish"替换为"Blowfish/ECB/PKCS5Padding"以获取Cipher实例，但是，如果您对密钥执行相同操作，则会失败。

键myKey必须是包含8个字符的Latin-1字符串。这使得128位的密钥。 Blowfish算法允许更大的密钥，但由于JRE中的美国出口限制，它们在Java中失败 - 美国允许加密但不强于NSA可以破解的。

CHARSET_ISO_8859_1是一个如下定义的常量：

final Charset CHARSET_ISO_8859_1 = Charset.forName("ISO-8859-1");

而Charset是java.nio.charset.Charset。

最后但并非最不重要的是，我相应地更改了加密Java代码。

Answer 5

通过声明模式和填充，您应该更明确地使用Cipher。这段代码是如何加密的？ String encryptedString中的实际内容是什么？是十六进制编码还是base64编码？如果它没有编码，肯定会成为麻烦的来源。

Answer 6

试试这个

private byte[] encrypt(String key, String plainText) throws GeneralSecurityException {

    SecretKey secret_key = new SecretKeySpec(key.getBytes(), ALGORITM);

    Cipher cipher = Cipher.getInstance(ALGORITM);
    cipher.init(Cipher.ENCRYPT_MODE, secret_key);

    return cipher.doFinal(plainText.getBytes());
}

在这里你可以找到带有enc / dec --- http://dexxtr.com/post/57145943236/blowfish-encrypt-and-decrypt-in-java-android

的全班

Answer 7

试试{ /** * 初始化密码以进行解密 / cipher.init(Cipher.DECRYPT_MODE,secretKey); /* * 初始化输入输出流 */ inStream = new FileInputStream(encryptedFile); outStream = new FileOutputStream(decryptedFile); 字节[]缓冲区=新字节[1024]；内里；而 ((len = inStream.read(buffer)) > 0) { outStream.write(cipher.update(buffer, 0, len)); outStream.flush(); } outStream.write(cipher.doFinal()); inStream.close(); outStream.close(); }

Answer 8

    try {
        /**
         * Initialize the cipher for decryption
         */
     cipher.init(Cipher.DECRYPT_MODE, secretKey);
        /**
         * Initialize input and output streams
         */
        inStream = new FileInputStream(encryptedFile);
        outStream = new FileOutputStream(decryptedFile);
        byte[] buffer = new byte[1024];
        int len;
        while ((len = inStream.read(buffer)) > 0) {
            outStream.write(cipher.update(buffer, 0, len));
            outStream.flush();
        }
        outStream.write(cipher.doFinal());
        inStream.close();
        outStream.close();
    }

...

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使用Blowfish在Java中解密

8 个答案: