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  • Android平台和java平台DES加密解密互通程序及其不能互通的原因(转)

    (建议使用RSA加密)

      网上的demo一搜一大堆,但是,基本上都是一知半解(包括我)。为什么呢?我在尝试分别在两个平台加密的时候,竟然发现Android DES 加密和java DES加密的程序不能互通。就是加密的结果不一样,更不要说Android平台的加密输入作为java DES的解密输出了。这样的话,客户端和服务器端就不能进行通信了。我网上之前也发帖子问了不少人,但是回答都不满意。

      今天部门的另外一个同事跟我说了一下,才解决了这个不能互通的问题。

      调用DES加密算法包最精要的就是下面两句话:

      Cipher cipher = Cipher.getInstance("DES/CBC/PKCS5Padding");
      cipher.init(Cipher.ENCRYPT_MODE, key, zeroIv);

      CBC是工作模式,DES一共有电子密码本模式(ECB)、加密分组链接模式(CBC)、加密反馈模式(CFB)和输出反馈模式(OFB)四种模式,

      PKCS5Padding是填充模式,还有其它的填充模式。

      然后,cipher.init()一共有三个参数:Cipher.ENCRYPT_MODE, key, zeroIv,zeroIv就是初始化向量,一个8为字符数组。

      工作模式、填充模式、初始化向量这三种因素一个都不能少。否则,如果你不指定的话,那么就要程序就要调用默认实现。问题就来了,这就与平台有关了。难怪网上一搜"DES加密结果不一致“,出现n多网页结果。(之前我并没有指定IV,被折磨了2周)

      源程序如下(从java平台到android平台,我根本没有更改一行代码):

      另外,一般情况下,加密后的结果都会用base64编码进行传输。

    java平台:

    主程序:

    public class testDES {
     
        /**
         * @param args
         * @throws Exception 
         */
        public static void main(String[] args) throws Exception {
            // TODO Auto-generated method stub
            String key = "12345678";
            String text = "12345678";
            String result1 = DES.encryptDES(text,key);
            String result2 = DES.decryptDES(result1, key);
            System.out.println(result1);
            System.out.println(result2);
        }
    }
    

      

    用到的DES加密类:

    import javax.crypto.Cipher;
    import javax.crypto.spec.IvParameterSpec;
    import javax.crypto.spec.SecretKeySpec;
     
    public class DES {
        private static byte[] iv = {1,2,3,4,5,6,7,8};
        public static String encryptDES(String encryptString, String encryptKey) throws Exception {
    //      IvParameterSpec zeroIv = new IvParameterSpec(new byte[8]);
            IvParameterSpec zeroIv = new IvParameterSpec(iv);
            SecretKeySpec key = new SecretKeySpec(encryptKey.getBytes(), "DES");
            Cipher cipher = Cipher.getInstance("DES/CBC/PKCS5Padding");
            cipher.init(Cipher.ENCRYPT_MODE, key, zeroIv);
            byte[] encryptedData = cipher.doFinal(encryptString.getBytes());
          
            return Base64.encode(encryptedData);
        }
        public static String decryptDES(String decryptString, String decryptKey) throws Exception {
            byte[] byteMi = new Base64().decode(decryptString);
            IvParameterSpec zeroIv = new IvParameterSpec(iv);
    //      IvParameterSpec zeroIv = new IvParameterSpec(new byte[8]);
            SecretKeySpec key = new SecretKeySpec(decryptKey.getBytes(), "DES");
            Cipher cipher = Cipher.getInstance("DES/CBC/PKCS5Padding");
            cipher.init(Cipher.DECRYPT_MODE, key, zeroIv);
            byte decryptedData[] = cipher.doFinal(byteMi);
          
            return new String(decryptedData);
        }
    }
    

      

    用到的BASE64工具类:

    import java.io.ByteArrayOutputStream;
    import java.io.IOException;
    import java.io.OutputStream;
     
     
     
    public class Base64 {
        private static final char[] legalChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/".toCharArray();
        /**
         * data[]进行编码
         * @param data
         * @return
         */
            public static String encode(byte[] data) {
                int start = 0;
                int len = data.length;
                StringBuffer buf = new StringBuffer(data.length * 3 / 2);
     
                int end = len - 3;
                int i = start;
                int n = 0;
     
                while (i <= end) {
                    int d = ((((int) data[i]) & 0x0ff) << 16)
                            | ((((int) data[i + 1]) & 0x0ff) << 8)
                            | (((int) data[i + 2]) & 0x0ff);
     
                    buf.append(legalChars[(d >> 18) & 63]);
                    buf.append(legalChars[(d >> 12) & 63]);
                    buf.append(legalChars[(d >> 6) & 63]);
                    buf.append(legalChars[d & 63]);
     
                    i += 3;
     
                    if (n++ >= 14) {
                        n = 0;
                        buf.append(" ");
                    }
                }
     
                if (i == start + len - 2) {
                    int d = ((((int) data[i]) & 0x0ff) << 16)
                            | ((((int) data[i + 1]) & 255) << 8);
     
                    buf.append(legalChars[(d >> 18) & 63]);
                    buf.append(legalChars[(d >> 12) & 63]);
                    buf.append(legalChars[(d >> 6) & 63]);
                    buf.append("=");
                } else if (i == start + len - 1) {
                    int d = (((int) data[i]) & 0x0ff) << 16;
     
                    buf.append(legalChars[(d >> 18) & 63]);
                    buf.append(legalChars[(d >> 12) & 63]);
                    buf.append("==");
                }
     
                return buf.toString();
            }
     
            private static int decode(char c) {
                if (c >= 'A' && c <= 'Z')
                    return ((int) c) - 65;
                else if (c >= 'a' && c <= 'z')
                    return ((int) c) - 97 + 26;
                else if (c >= '0' && c <= '9')
                    return ((int) c) - 48 + 26 + 26;
                else
                    switch (c) {
                    case '+':
                        return 62;
                    case '/':
                        return 63;
                    case '=':
                        return 0;
                    default:
                        throw new RuntimeException("unexpected code: " + c);
                    }
            }
     
            /**
             * Decodes the given Base64 encoded String to a new byte array. The byte
             * array holding the decoded data is returned.
             */
     
            public static byte[] decode(String s) {
     
                ByteArrayOutputStream bos = new ByteArrayOutputStream();
                try {
                    decode(s, bos);
                } catch (IOException e) {
                    throw new RuntimeException();
                }
                byte[] decodedBytes = bos.toByteArray();
                try {
                    bos.close();
                    bos = null;
                } catch (IOException ex) {
                    System.err.println("Error while decoding BASE64: " + ex.toString());
                }
                return decodedBytes;
            }
     
            private static void decode(String s, OutputStream os) throws IOException {
                int i = 0;
     
                int len = s.length();
     
                while (true) {
                    while (i < len && s.charAt(i) <= ' ')
                        i++;
     
                    if (i == len)
                        break;
     
                    int tri = (decode(s.charAt(i)) << 18)
                            + (decode(s.charAt(i + 1)) << 12)
                            + (decode(s.charAt(i + 2)) << 6)
                            + (decode(s.charAt(i + 3)));
     
                    os.write((tri >> 16) & 255);
                    if (s.charAt(i + 2) == '=')
                        break;
                    os.write((tri >> 8) & 255);
                    if (s.charAt(i + 3) == '=')
                        break;
                    os.write(tri & 255);
     
                    i += 4;
                }
            }
             
    }
    

      

     

    adnroid平台的主函数:

    public class main extends Activity {
        /** Called when the activity is first created. */
        @Override
        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.main);
            
            String key = "12345678";
            String text = "12345678";
             
             
            try {
                String result1 = DES.encryptDES(text,key);
                String result2 = DES.decryptDES(result1, key);
                Log.i("DES encode text is ", result1);
                Log.i("DES encode text is ", result2);
            } catch (Exception e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }    
        }
    }
    

      

    通过查看log日志就可以看到结果。

    两个平台的结果是一样的,都是:

    加密结果:X2p9Uo45Tzk6Ntu6W7Ev+Q==
    解密结果:12345678

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  • 原文地址:https://www.cnblogs.com/aprz512/p/4730537.html
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