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。
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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;
}
}
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2、使用
新建Android工程
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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 ;
}
}
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3、打印结果
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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
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