Java中常用加密/解密方法详解

安全问题已经成为一个越来越重要的问题，在java中如何对重要数据进行加密解密是本文的主要内容。

一、常用的加密/解密算法

1.base64

严格来说base64并不是一种加密/解密算法，而是一种编码方式。base64不生成密钥，通过base64编码后的密文就可以直接“翻译”为明文，但是可以通过向明文中添加混淆字符来达到加密的效果。

2.des

des是一种基于56位密钥的对称算法，1976年被美国联邦*的国家标准局确定为联邦资料处理标准（fips），随后在国际上广泛流传开来。现在des已经不是一种安全的加密算法，已被公开破解，现在des已经被高级加密标准（aes）所代替。

3.3des

3des是des的一种派生算法，主要提升了des的一些实用所需的安全性。

4.aes

aes是现在对称加密算法中最流行的算法之一。

二、实现所需的一些库

为了实现上述的算法，我们可以实用jdk自带的实现，也可以使用一些开源的第三方库，例如bouncy castle（）和comnons codec（）。

三、具体实现

1.base64

package com.tancky.security;
import java.io.ioexception;
import sun.misc.base64decoder;
import sun.misc.base64encoder;
public class base64demo {
 private static string src = "testbase64";
 public static void main(string[] args) {
 base64demo.jdkbase64();
 base64demo.commonscodecbase64 ();
 base64demo.bouncycastlebase64 ();
 }
 //使用jdk的base64实现，
 public static void jdkbase64 (){
 base64encoder encoder = new base64encoder();
 string encode = encoder.encode(base64demo.src.getbytes());
 system.out.println("encode: " + encode);
 base64decoder decoder = new base64decoder();
 try {
  string decode = new string ( decoder.decodebuffer(encode));
  system.out.println("decode: " + decode);
 } catch (ioexception e) {
  e.printstacktrace();
 } 
 }
 //使用apache的commonscodec实现
 public static void commonscodecbase64 (){
 byte[] encodebytes = org.apache.commons.codec.binary.base64.encodebase64(base64demo.src.getbytes());
 string encode = new string (encodebytes);
 system.out.println("encode: " + encode);
 byte[] decodebytes = org.apache.commons.codec.binary.base64.decodebase64(encode);
 string decode = new string(decodebytes);
 system.out.println("decode: " + decode);
 }
 //使用bouncycastlede实现
 public static void bouncycastlebase64 () {
 byte[] encodebytes = org.bouncycastle.util.encoders.base64.encode(base64demo.src.getbytes()) ;
 string encode = new string (encodebytes);
 system.out.println("encode: " + encode);
 byte[] decodebytes = org.bouncycastle.util.encoders.base64.decode(encode);
 string decode = new string(decodebytes);
 system.out.println("decode: " + decode);
 }
}

2.des

package com.tancky.security;
import java.security.invalidkeyexception;
import java.security.key;
import java.security.nosuchalgorithmexception;
import java.security.nosuchproviderexception;
import java.security.security;
import java.security.spec.invalidkeyspecexception;
import javax.crypto.badpaddingexception;
import javax.crypto.cipher;
import javax.crypto.illegalblocksizeexception;
import javax.crypto.keygenerator;
import javax.crypto.nosuchpaddingexception;
import javax.crypto.secretkey;
import javax.crypto.secretkeyfactory;
import javax.crypto.spec.deskeyspec;
import org.bouncycastle.jce.provider.bouncycastleprovider;
import org.bouncycastle.util.encoders.hex;
public class desdemo {
 private static string src = "testdes";
 public static void jdkdes () {
 try {
  //生成密钥key
  keygenerator keygenerator = keygenerator.getinstance("des");
  keygenerator.init(56);
  secretkey secretkey = keygenerator.generatekey();
  byte[] byteskey = secretkey.getencoded();
  //key转换
  deskeyspec desedekeyspec = new deskeyspec(byteskey);
  secretkeyfactory factory = secretkeyfactory.getinstance("des");
  key convertsecretkey = factory.generatesecret(desedekeyspec);
  //加密
  cipher cipher = cipher.getinstance("des/ecb/pkcs5padding");
  cipher.init(cipher.encrypt_mode, convertsecretkey);
  byte[] encoderesult = cipher.dofinal(desdemo.src.getbytes());
  system.out.println("desencode :" + hex.tohexstring(encoderesult));
  //解密
  cipher.init(cipher.decrypt_mode,convertsecretkey);
  byte[] decoderesult = cipher.dofinal(encoderesult);
  system.out.println("desdncode :" + new string (decoderesult));
 } catch (nosuchalgorithmexception e) {
  e.printstacktrace();
 } catch (invalidkeyexception e) {
  // todo 自动生成的 catch 块
  e.printstacktrace();
 } catch (invalidkeyspecexception e) {
  // todo 自动生成的 catch 块
  e.printstacktrace();
 } catch (nosuchpaddingexception e) {
  // todo 自动生成的 catch 块
  e.printstacktrace();
 } catch (illegalblocksizeexception e) {
  // todo 自动生成的 catch 块
  e.printstacktrace();
 } catch (badpaddingexception e) {
  // todo 自动生成的 catch 块
  e.printstacktrace();
 }
 }
 public static void bcdes (){
 try {
  //使用bouncycastle 的des加密
  security.addprovider(new bouncycastleprovider());
  //生成密钥key
  keygenerator keygenerator = keygenerator.getinstance("des","bc");
  keygenerator.init(56);
  secretkey secretkey = keygenerator.generatekey();
  byte[] byteskey = secretkey.getencoded();
  //key转换
  deskeyspec desedekeyspec = new deskeyspec(byteskey);
  secretkeyfactory factory = secretkeyfactory.getinstance("des");
  key convertsecretkey = factory.generatesecret(desedekeyspec);
  //加密
  cipher cipher = cipher.getinstance("des/ecb/pkcs5padding");
  cipher.init(cipher.encrypt_mode, convertsecretkey);
  byte[] encoderesult = cipher.dofinal(desdemo.src.getbytes());
  system.out.println("desencode :" + hex.tohexstring(encoderesult));
  //解密
  cipher.init(cipher.decrypt_mode,convertsecretkey);
  byte[] decoderesult = cipher.dofinal(encoderesult);
  system.out.println("desdncode :" + new string (decoderesult));

 } catch (nosuchalgorithmexception e) {
  e.printstacktrace();
 } catch (invalidkeyexception e) {
  // todo 自动生成的 catch 块
  e.printstacktrace();
 } catch (invalidkeyspecexception e) {
  // todo 自动生成的 catch 块
  e.printstacktrace();
 } catch (nosuchpaddingexception e) {
  // todo 自动生成的 catch 块
  e.printstacktrace();
 } catch (illegalblocksizeexception e) {
  // todo 自动生成的 catch 块
  e.printstacktrace();
 } catch (badpaddingexception e) {
  // todo 自动生成的 catch 块
  e.printstacktrace();
 } catch (nosuchproviderexception e) {
  // todo 自动生成的 catch 块
  e.printstacktrace();
 }
 }
 public static void main(string[] args) {
 desdemo.jdkdes ();
 desdemo.bcdes();
 }
}

3.3des

package com.tancky.security;
import java.security.invalidkeyexception;
import java.security.key;
import java.security.nosuchalgorithmexception;
import java.security.nosuchproviderexception;
import java.security.security;
import java.security.spec.invalidkeyspecexception;
import javax.crypto.badpaddingexception;
import javax.crypto.cipher;
import javax.crypto.illegalblocksizeexception;
import javax.crypto.keygenerator;
import javax.crypto.nosuchpaddingexception;
import javax.crypto.secretkey;
import javax.crypto.secretkeyfactory;
import javax.crypto.spec.desedekeyspec;
import org.bouncycastle.jce.provider.bouncycastleprovider;
import org.bouncycastle.util.encoders.hex;
public class tripledesdemo {
 private static string src = "testtripledes";
 public static void jdktripledes () {
 try {
  //生成密钥key
  keygenerator keygenerator = keygenerator.getinstance("desede");
  keygenerator.init(168);
  secretkey secretkey = keygenerator.generatekey();
  byte[] byteskey = secretkey.getencoded();
  //key转换
  desedekeyspec desedekeyspec = new desedekeyspec(byteskey);
  secretkeyfactory factory = secretkeyfactory.getinstance("desede");
  key convertsecretkey = factory.generatesecret(desedekeyspec);
  //加密
  cipher cipher = cipher.getinstance("desede/ecb/pkcs5padding");
  cipher.init(cipher.encrypt_mode, convertsecretkey);
  byte[] encoderesult = cipher.dofinal(tripledesdemo.src.getbytes());
  system.out.println("tripledesencode :" + hex.tohexstring(encoderesult));
  //解密
  cipher.init(cipher.decrypt_mode,convertsecretkey);
  byte[] decoderesult = cipher.dofinal(encoderesult);
  system.out.println("tripledesdncode :" + new string (decoderesult));
 } catch (nosuchalgorithmexception e) {
  e.printstacktrace();
 } catch (invalidkeyexception e) {
  // todo 自动生成的 catch 块
  e.printstacktrace();
 } catch (invalidkeyspecexception e) {
  // todo 自动生成的 catch 块
  e.printstacktrace();
 } catch (nosuchpaddingexception e) {
  // todo 自动生成的 catch 块
  e.printstacktrace();
 } catch (illegalblocksizeexception e) {
  // todo 自动生成的 catch 块
  e.printstacktrace();
 } catch (badpaddingexception e) {
  // todo 自动生成的 catch 块
  e.printstacktrace();
 }
 }
public static void bctripledes () {
 try {
  security.addprovider(new bouncycastleprovider());
  //生成密钥key
  keygenerator keygenerator = keygenerator.getinstance("desede","bc");
  keygenerator.getprovider();
  keygenerator.init(168);
  secretkey secretkey = keygenerator.generatekey();
  byte[] byteskey = secretkey.getencoded();
  //key转换
  desedekeyspec desedekeyspec = new desedekeyspec(byteskey);
  secretkeyfactory factory = secretkeyfactory.getinstance("desede");
  key convertsecretkey = factory.generatesecret(desedekeyspec);
  //加密
  cipher cipher = cipher.getinstance("desede/ecb/pkcs5padding");
  cipher.init(cipher.encrypt_mode, convertsecretkey);
  byte[] encoderesult = cipher.dofinal(tripledesdemo.src.getbytes());
  system.out.println("tripledesencode :" + hex.tohexstring(encoderesult));
  //解密
  cipher.init(cipher.decrypt_mode,convertsecretkey);
  byte[] decoderesult = cipher.dofinal(encoderesult);
  system.out.println("tripledesdncode :" + new string (decoderesult));
 } catch (nosuchalgorithmexception e) {
  e.printstacktrace();
 } catch (invalidkeyexception e) {
  // todo 自动生成的 catch 块
  e.printstacktrace();
 } catch (invalidkeyspecexception e) {
  // todo 自动生成的 catch 块
  e.printstacktrace();
 } catch (nosuchpaddingexception e) {
  // todo 自动生成的 catch 块
  e.printstacktrace();
 } catch (illegalblocksizeexception e) {
  // todo 自动生成的 catch 块
  e.printstacktrace();
 } catch (badpaddingexception e) {
  // todo 自动生成的 catch 块
  e.printstacktrace();
 } catch (nosuchproviderexception e) {
  // todo 自动生成的 catch 块
  e.printstacktrace();
 }
 }
 public static void main(string[] args) {
 jdktripledes ();
 bctripledes ();
 }
}

4.aes

package com.tancky.security;
import java.security.invalidkeyexception;
import java.security.key;
import java.security.nosuchalgorithmexception;
import java.security.nosuchproviderexception;
import java.security.securerandom;
import java.security.security;
import javax.crypto.badpaddingexception;
import javax.crypto.cipher;
import javax.crypto.illegalblocksizeexception;
import javax.crypto.keygenerator;
import javax.crypto.nosuchpaddingexception;
import javax.crypto.secretkey;
import javax.crypto.spec.secretkeyspec;
import org.bouncycastle.jce.provider.bouncycastleprovider;
import org.bouncycastle.util.encoders.hex;
public class aesdemo {
 private static string src = "testaes";
 public static void jdkaes (){
 try {
  //生成key
  keygenerator keygenerator = keygenerator.getinstance("aes");
  keygenerator.init(128); 
  //keygenerator.init(128, new securerandom("seedseedseed".getbytes())); 
  //使用上面这种初始化方法可以特定种子来生成密钥，这样加密后的密文是唯一固定的。
  secretkey secretkey = keygenerator.generatekey();
  byte[] keybytes = secretkey.getencoded();
  //key转换
  key key = new secretkeyspec(keybytes, "aes");
  //加密
  cipher cipher = cipher.getinstance("aes/ecb/pkcs5padding");
  cipher.init(cipher.encrypt_mode, key);
  byte[] encoderesult = cipher.dofinal(aesdemo.src.getbytes());
  system.out.println("aesencode : " + hex.tohexstring(encoderesult) );
  //解密
  cipher.init(cipher.decrypt_mode, key);
  byte[] decoderesult = cipher.dofinal(encoderesult);
  system.out.println("aesdecode : " + new string (decoderesult));
 } catch (nosuchalgorithmexception e) {
  // todo 自动生成的 catch 块
  e.printstacktrace();
 } catch (nosuchpaddingexception e) {
  // todo 自动生成的 catch 块
  e.printstacktrace();
 } catch (invalidkeyexception e) {
  // todo 自动生成的 catch 块
  e.printstacktrace();
 } catch (illegalblocksizeexception e) {
  // todo 自动生成的 catch 块
  e.printstacktrace();
 } catch (badpaddingexception e) {
  // todo 自动生成的 catch 块
  e.printstacktrace();
 }
 }
 public static void bcaes (){
 try {
  //使用bouncycastle 的des加密
  security.addprovider(new bouncycastleprovider());
  //生成key
  keygenerator keygenerator = keygenerator.getinstance("aes","bc");
  keygenerator.getprovider();
  keygenerator.init(128); 
  secretkey secretkey = keygenerator.generatekey();
  byte[] keybytes = secretkey.getencoded();
  //key转换
  key key = new secretkeyspec(keybytes, "aes");
  //加密
  cipher cipher = cipher.getinstance("aes/ecb/pkcs5padding");
  cipher.init(cipher.encrypt_mode, key);
  byte[] encoderesult = cipher.dofinal(aesdemo.src.getbytes());
  system.out.println("aesencode : " + hex.tohexstring(encoderesult) );
  //解密
  cipher.init(cipher.decrypt_mode, key);
  byte[] decoderesult = cipher.dofinal(encoderesult);
  system.out.println("aesdecode : " + new string (decoderesult));
 } catch (nosuchalgorithmexception e) {
  // todo 自动生成的 catch 块
  e.printstacktrace();
 } catch (nosuchpaddingexception e) {
  // todo 自动生成的 catch 块
  e.printstacktrace();
 } catch (invalidkeyexception e) {
  // todo 自动生成的 catch 块
  e.printstacktrace();
 } catch (illegalblocksizeexception e) {
  // todo 自动生成的 catch 块
  e.printstacktrace();
 } catch (badpaddingexception e) {
  // todo 自动生成的 catch 块
  e.printstacktrace();
 } catch (nosuchproviderexception e) {
  // todo 自动生成的 catch 块
  e.printstacktrace();
 }
 }
 public static void main(string[] args) {
 jdkaes();
 bcaes();
 }
}

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