DES加密解密

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;
import java.security.Key;

import javax.crypto.Cipher;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESedeKeySpec;
import javax.crypto.spec.IvParameterSpec;

/**
 * Date: 2019/4/1
 * autor:Wayne
 */

public class DesUtils
{ // 密钥
//  private final static String secretKey = "my.oschina.net/penngo?#@" ;
  // 向量
  private final static String iv = "01234567" ;
  // 加解密统一使用的编码方式
  private final static String encoding = "utf-8" ;

  /**
   * 3DES加密
   *
   * @param plainText 普通文本
   * @return
   * @throws Exception
   */
  public static String encode(String secretKey, String plainText) throws Exception {
    Key deskey = null ;
    DESedeKeySpec spec = new DESedeKeySpec(secretKey.getBytes());
    SecretKeyFactory keyfactory = SecretKeyFactory.getInstance( "desede" );
    deskey = keyfactory.generateSecret(spec);

    Cipher cipher = Cipher.getInstance( "desede/CBC/PKCS5Padding" );
    IvParameterSpec ips = new IvParameterSpec(iv.getBytes());
    cipher.init(Cipher.ENCRYPT_MODE, deskey, ips);
    byte [] encryptData = cipher.doFinal(plainText.getBytes(encoding));
    return Base64.encode(encryptData);
  }

  /**
   * 3DES解密
   *
   * @param encryptText 加密文本
   * @return
   * @throws Exception
   */
  public static String decode(String secretKey,String encryptText) throws Exception {
    Key deskey = null ;
    DESedeKeySpec spec = new DESedeKeySpec(secretKey.getBytes());
    SecretKeyFactory keyfactory = SecretKeyFactory.getInstance( "desede" );
    deskey = keyfactory.generateSecret(spec);
    Cipher cipher = Cipher.getInstance( "desede/CBC/PKCS5Padding" );
    IvParameterSpec ips = new IvParameterSpec(iv.getBytes());
    cipher.init(Cipher.DECRYPT_MODE, deskey, ips);

    byte [] decryptData = cipher.doFinal(Base64.decode(encryptText));

    return new String(decryptData, encoding);
  }

  public static String padding(String str) {
    byte[] oldByteArray;
    try {
      oldByteArray = str.getBytes("UTF8");
      int numberToPad = 8 - oldByteArray.length % 8;
      byte[] newByteArray = new byte[oldByteArray.length + numberToPad];
      System.arraycopy(oldByteArray, 0, newByteArray, 0,
          oldByteArray.length);
      for (int i = oldByteArray.length; i < newByteArray.length; ++i) {
        newByteArray[i] = 0;
      }
      return new String(newByteArray, "UTF8");
    } catch (UnsupportedEncodingException e) {
      System.out.println("Crypter.padding UnsupportedEncodingException");
    }
    return null;
  }

  /**
   * Base64编码工具类
   *
   */
  public static class Base64 {
    private static final char [] legalChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/" .toCharArray();

    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 ;
      }
    }
  }

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

    String secretKey = "my.oschina.net/penngo?#@" ;

    String plainText = "来自http://my.oschina.net/penngo的博客";
    String encryptText = DesUtils.encode(secretKey,plainText);
    System.out.println(encryptText);
    System.out.println(DesUtils.decode(secretKey,encryptText));


  }
}

要是得到一个MD5值

import android.content.Context;
import android.content.pm.PackageInfo;
import android.content.pm.PackageManager;
import android.content.pm.Signature;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

/**
 * Date: 2019/4/1
 * autor:Wayne
 */

public class SignUtils {

  public static String getPackageSignInfo(Context context, String packageName) {
    try {
      PackageInfo pis = context.getPackageManager().
          getPackageInfo(packageName, PackageManager.GET_SIGNATURES);
      Signature[] sigs = pis.signatures;
      String sig = new String(sigs[0].toChars());
      return sig;
    } catch (Exception e) {
      return "";
    }
  }

  public static String MD5Encode(String str) {
    try {
      byte[] digest = MessageDigest.getInstance("MD5").digest(str.getBytes());
      StringBuffer stringBuffer = new StringBuffer();
      for (byte b : digest) {
        String toHexString = Integer.toHexString(b & 255);
        if (toHexString.length() == 1) {
          stringBuffer.append(0);
        }
        stringBuffer.append(toHexString);
      }
      return stringBuffer.toString();
    } catch (NoSuchAlgorithmException e) {
      e.printStackTrace();
      return null;
    }
  }

最后：前端后端配合加解密

//请求得到加密的数据
String data= json.getString(data);
//md5值
String packageSignInfo = SignUtils.getPackageSignInfo(context, CommonUtils.getPackageName());
String md5 = SignUtils.MD5Encode(packageSignInfo);
//解密后的数据
String data=DesUtils.decode(md5,data);