Android AES加密工具类分享

1、aes加密工具类

java不支持pkcs7padding，只支持pkcs5padding。我们知道加密算法由算法+模式+填充组成，下一篇介绍ios和android通用的aes加密，本篇文章使用pkcs5padding加密方式。

package com.example.aesdemo;

import java.io.unsupportedencodingexception;
import javax.crypto.cipher;
import javax.crypto.spec.secretkeyspec;
 
///** aes对称加密解密类 **/
public class aeshelper {
 
 // /** 算法/模式/填充 **/
 private static final string ciphermode = "aes/ecb/pkcs5padding";
 
 ///** 创建密钥 **/
 private static secretkeyspec createkey(string password) {
 byte[] data = null;
 if (password == null) {
  password = "";
 }
 stringbuffer sb = new stringbuffer(32);
 sb.append(password);
 while (sb.length() < 32) {
  sb.append("0");
 }
 if (sb.length() > 32) {
  sb.setlength(32);
 }
 
 try {
  data = sb.tostring().getbytes("utf-8");
 } catch (unsupportedencodingexception e) {
  e.printstacktrace();
 }
 return new secretkeyspec(data, "aes");
 }
 
 // /** 加密字节数据 **/
 public static byte[] encrypt(byte[] content, string password) {
 try {
  secretkeyspec key = createkey(password);
  system.out.println(key);
  cipher cipher = cipher.getinstance(ciphermode);
  cipher.init(cipher.encrypt_mode, key);
  byte[] result = cipher.dofinal(content);
  return result;
 } catch (exception e) {
  e.printstacktrace();
 }
 return null;
 }
 
 ///** 加密(结果为16进制字符串) **/
 public static string encrypt(string content, string password) {
 byte[] data = null;
 try {
  data = content.getbytes("utf-8");
 } catch (exception e) {
  e.printstacktrace();
 }
 data = encrypt(data, password);
 string result = byte2hex(data);
 return result;
 }
 
 // /** 解密字节数组 **/
 public static byte[] decrypt(byte[] content, string password) {
 try {
  secretkeyspec key = createkey(password);
  cipher cipher = cipher.getinstance(ciphermode);
  cipher.init(cipher.decrypt_mode, key);
  byte[] result = cipher.dofinal(content);
  return result;
 } catch (exception e) {
  e.printstacktrace();
 }
 return null;
 }
 
 ///** 解密16进制的字符串为字符串 **/
 public static string decrypt(string content, string password) {
 byte[] data = null;
 try {
  data = hex2byte(content);
 } catch (exception e) {
  e.printstacktrace();
 }
 data = decrypt(data, password);
 if (data == null)
  return null;
 string result = null;
 try {
  result = new string(data, "utf-8");
 } catch (unsupportedencodingexception e) {
  e.printstacktrace();
 }
 return result;
 }
 
 // /** 字节数组转成16进制字符串 **/
 public static string byte2hex(byte[] b) { // 一个字节的数，
 stringbuffer sb = new stringbuffer(b.length * 2);
 string tmp = "";
 for (int n = 0; n < b.length; n++) {
  // 整数转成十六进制表示
  tmp = (java.lang.integer.tohexstring(b[n] & 0xff));
  if (tmp.length() == 1) {
  sb.append("0");
  }
  sb.append(tmp);
 }
 return sb.tostring().touppercase(); // 转成大写
 }
 
 // /** 将hex字符串转换成字节数组 **/
 private static byte[] hex2byte(string inputstring) {
 if (inputstring == null || inputstring.length() < 2) {
  return new byte[0];
 }
 inputstring = inputstring.tolowercase();
 int l = inputstring.length() / 2;
 byte[] result = new byte[l];
 for (int i = 0; i < l; ++i) {
  string tmp = inputstring.substring(2 * i, 2 * i + 2);
  result[i] = (byte) (integer.parseint(tmp, 16) & 0xff);
 }
 return result;
 }
}

2、使用

新建android工程

package com.example.aesdemo;

import android.os.bundle;
import android.app.activity;
import android.view.menu;
import android.util.log; 

public class mainactivity extends activity {
		
 protected void oncreate(bundle savedinstancestate) {
 		super.oncreate(savedinstancestate);
 		setcontentview(r.layout.activity_main);
	
	 string masterpassword = "a"; 
	 string originaltext = "于"; 

	 try { 
	  string encryptingcode = aeshelper.encrypt(originaltext,masterpassword); 
//	  system.out.println("加密结果为 " + encryptingcode); 
	  log.i("加密结果为 ",encryptingcode); 
	  string decryptingcode = aeshelper.decrypt(encryptingcode,masterpassword); 
//	  system.out.println("解密结果为 " + decryptingcode); 
	  log.i("解密结果",decryptingcode); 
	  } catch (exception e) { 
	  // todo auto-generated catch block 
	  e.printstacktrace(); 
	 } 	
	}

	@override
	public boolean oncreateoptionsmenu(menu menu) {
		// inflate the menu; this adds items to the action bar if it is present.
		getmenuinflater().inflate(r.menu.main, menu);
		return true;
	}
}

3、打印结果

09-19 10:41:05.467: i/加密结果为(707): e55c24701f6380478e1940addfd08d22
09-19 10:41:05.467: i/解密结果(707): 于