How to use java 3DES encryption and decryption

This time I will show you how to use java 3DES encryption and decryption, and what are the precautions for using java 3DES encryption and decryption. The following is a practical case, let's take a look.

<pre name="code" class="java">Java写的加密解密算法及调用范例

1、.JAVA算法范例

package Common.JUtility;

 

import javax.crypto.*;

import javax.crypto.spec.SecretKeySpec;

import com.sun.org.apache.xerces.internal.impl.dv.util.Base64;

 

public class EncryptUtils {

 

    /// <summary>

    /// 3des解码

    /// </summary>

    /// <param name="value">待解密字符串</param>

    /// <param name="key">原始密钥字符串</param>

    /// <returns></returns>

    public static String Decrypt3DES(String value, String key) throws Exception {

        byte[] b = decryptMode(GetKeyBytes(key), Base64.decode(value));

        return new String(b);

    }

 

    /// <summary>

    /// 3des加密

    /// </summary>

    /// <param name="value">待加密字符串</param>

    /// <param name="strKey">原始密钥字符串</param>

    /// <returns></returns>

    public static String Encrypt3DES(String value, String key) throws Exception {

        String str = byte2Base64(encryptMode(GetKeyBytes(key), value.getBytes()));

        return str;

    }

 

    //计算24位长的密码byte值,首先对原始密钥做MD5算hash值，再用前8位数据对应补全后8位

    public static byte[] GetKeyBytes(String strKey) throws Exception {

        if (null == strKey || strKey.length() < 1)

            throw new Exception("key is null or empty!");

 

        java.security.MessageDigest alg = java.security.MessageDigest.getInstance("MD5");

        alg.update(strKey.getBytes());

        byte[] bkey = alg.digest();

        System.out.println("md5key.length=" + bkey.length);

        System.out.println("md5key=" + byte2hex(bkey));

        int start = bkey.length;

        byte[] bkey24 = new byte[24];

        for (int i = 0; i < start; i++) {

            bkey24[i] = bkey[i];

        }

        for (int i = start; i < 24; i++) {//为了与.net16位key兼容

            bkey24[i] = bkey[i - start];

        }

 

        System.out.println("byte24key.length=" + bkey24.length);

        System.out.println("byte24key=" + byte2hex(bkey24));

        return bkey24;

    }

 

    private static final String Algorithm = "DESede"; //定义 加密算法,可用 DES,DESede,Blowfish       

 

    //keybyte为加密密钥，长度为24字节

    //src为被加密的数据缓冲区（源）  

    public static byte[] encryptMode(byte[] keybyte, byte[] src) {

        try {

            //生成密钥

            SecretKey deskey = new SecretKeySpec(keybyte, Algorithm); //加密 

            Cipher c1 = Cipher.getInstance(Algorithm);

            c1.init(Cipher.ENCRYPT_MODE, deskey);

            return c1.doFinal(src);

       } catch (java.security.NoSuchAlgorithmException e1) {

            e1.printStackTrace();

        } catch (javax.crypto.NoSuchPaddingException e2) {

            e2.printStackTrace();

        } catch (java.lang.Exception e3) {

            e3.printStackTrace();

        }

        return null;

    }

 

    //keybyte为加密密钥，长度为24字节  

    //src为加密后的缓冲区

    public static byte[] decryptMode(byte[] keybyte, byte[] src) {

        try { //生成密钥   

            SecretKey deskey = new SecretKeySpec(keybyte, Algorithm);

            //解密     

            Cipher c1 = Cipher.getInstance(Algorithm);

            c1.init(Cipher.DECRYPT_MODE, deskey);

            return c1.doFinal(src);

        } catch (java.security.NoSuchAlgorithmException e1) {

            e1.printStackTrace();

        } catch (javax.crypto.NoSuchPaddingException e2) {

            e2.printStackTrace();

        } catch (java.lang.Exception e3) {

            e3.printStackTrace();

        }

        return null;

    }

 

    //转换成base64编码

    public static String byte2Base64(byte[] b) {

        return Base64.encode(b);

    }

 

    //转换成十六进制字符串  

    public static String byte2hex(byte[] b) {

        String hs = "";

        String stmp = "";

        for (int n = 0; n < b.length; n++) {

            stmp = (java.lang.Integer.toHexString(b[n] & 0XFF));

            if (stmp.length() == 1)

                hs = hs + "0" + stmp;

            else

                hs = hs + stmp;

            if (n < b.length - 1)

                hs = hs + ":";

        }

        return hs.toUpperCase();

    }

}

 

2、JAVA 算法调用范例

package test.com;

 

import com.sun.org.apache.xerces.internal.impl.dv.util.Base64;

import Common.JUtility.EncryptUtils;//用原始密钥经MD5转换和补位后的新密钥来做3DES加密解密

 

public class Test3DES {

   

    public static void main(String[] args) {

        String key = "abcd1234";

        String password = "password";

        System.out.println("key=" + key + ",password=" + password);

        System.out.println();

        System.out.println("----------示例开始：使用java写的算法加密解密-----------");

       try {

            String encrypt = "";

            String decrypt = "";

           byte[] bkey = EncryptUtils.GetKeyBytes(key);

            encrypt = EncryptUtils.byte2Base64(EncryptUtils.encryptMode(bkey, password.getBytes()));

            System.out.println("用预转换密钥算加密结果=" + encrypt);

            System.out.println("加密后base64表示=" + EncryptUtils.byte2hex(Base64.decode(encrypt)));

            System.out.println("调用原始密钥算加密结果=" + EncryptUtils.Encrypt3DES(password, key));

 

           try {

                decrypt = new String(EncryptUtils.decryptMode(bkey, Base64.decode(encrypt)));

                System.out.println("用预转换密钥算解密结果=" + decrypt);

                System.out.println("调用原始密钥算解密结果=" + EncryptUtils.Decrypt3DES(encrypt, key));

            } catch (Exception ex) {

                System.out.println("Exception:" + ex.getMessage());

            }

        } catch (Exception ex) {

            System.out.println("Exception:" + ex.getMessage());

        }

        System.out.println("----------示例结束：使用java写的算法加密解密-----------");

    }

}

 

3、(7)的运算结果

key=abcd1234,password=password

 

----------示例开始：使用java写的算法加密解密-----------

md5key.length=16

md5key=E1:9D:5C:D5:AF:03:78:DA:05:F6:3F:89:1C:74:67:AF

byte24key.length=24

byte24key=E1:9D:5C:D5:AF:03:78:DA:05:F6:3F:89:1C:74:67:AF:E1:9D:5C:D5:AF:03:78:DA

用预转换密钥算加密结果=ftwPzxFH4WpzT4Orq8uSLQ==

 

加密后base64表示=7E:DC:0F:CF:11:47:E1:6A:73:4F:83:AB:AB:CB:92:2D

md5key.length=16

md5key=E1:9D:5C:D5:AF:03:78:DA:05:F6:3F:89:1C:74:67:AF

byte24key.length=24

byte24key=E1:9D:5C:D5:AF:03:78:DA:05:F6:3F:89:1C:74:67:AF:E1:9D:5C:D5:AF:03:78:DA

调用原始密钥算加密结果=ftwPzxFH4WpzT4Orq8uSLQ==

 

用预转换密钥算解密结果=password

md5key.length=16

md5key=E1:9D:5C:D5:AF:03:78:DA:05:F6:3F:89:1C:74:67:AF

byte24key.length=24

byte24key=E1:9D:5C:D5:AF:03:78:DA:05:F6:3F:89:1C:74:67:AF:E1:9D:5C:D5:AF:03:78:DA

调用原始密钥算解密结果=password

----------示例结束：使用java写的算法加密解密-----------

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