AES加解密算法在Android中的应用及Android4.2以上版本调用问题

　　

 

　　密码学中的高级加密标准（Advanced Encryption Standard，AES），又称高级加密标准Rijndael加密法，是美国联邦政府采用的一种区块加密标准。这个标准用来替代原先的DES，已经被多方分析且广为全世界所使用。该算法为比利时密码学家Joan Daemen和Vincent Rijmen所设计，结合两位作者的名字，以Rijndael之命名之。

 要区别4.2以上版本的调用方法，否则将会出现意想不到的问题。

AESCipher.java

package com.test;import java.security.SecureRandom;import javax.crypto.Cipher;import javax.crypto.KeyGenerator;import javax.crypto.SecretKey;import javax.crypto.spec.SecretKeySpec;public class AESCipher {public static String encrypt(String key, String src) throws Exception {           byte[] rawKey = getRawKey(key.getBytes());           byte[] result = encrypt(rawKey, src.getBytes());           return toHex(result);       }              public static String decrypt(String key, String encrypted) throws Exception {           byte[] rawKey = getRawKey(key.getBytes());           byte[] enc = toByte(encrypted);           byte[] result = decrypt(rawKey, enc);           return new String(result);       }         private static byte[] getRawKey(byte[] seed) throws Exception {           KeyGenerator kgen = KeyGenerator.getInstance("AES");         // SHA1PRNG 强随机种子算法, 要区别4.2以上版本的调用方法         SecureRandom sr = null;       if (android.os.Build.VERSION.SDK_INT >=  17) {         sr = SecureRandom.getInstance("SHA1PRNG", "Crypto");       } else {         sr = SecureRandom.getInstance("SHA1PRNG");       }         sr.setSeed(seed);           kgen.init(256, sr); //256 bits or 128 bits,192bits        SecretKey skey = kgen.generateKey();           byte[] raw = skey.getEncoded();           return raw;       }                private static byte[] encrypt(byte[] key, byte[] src) throws Exception {           SecretKeySpec skeySpec = new SecretKeySpec(key, "AES");           Cipher cipher = Cipher.getInstance("AES");           cipher.init(Cipher.ENCRYPT_MODE, skeySpec);           byte[] encrypted = cipher.doFinal(src);           return encrypted;       }         private static byte[] decrypt(byte[] key, byte[] encrypted) throws Exception {           SecretKeySpec skeySpec = new SecretKeySpec(key, "AES");           Cipher cipher = Cipher.getInstance("AES");           cipher.init(Cipher.DECRYPT_MODE, skeySpec);           byte[] decrypted = cipher.doFinal(encrypted);           return decrypted;       }         public static String toHex(String txt) {           return toHex(txt.getBytes());       }       public static String fromHex(String hex) {           return new String(toByte(hex));       }              public static byte[] toByte(String hexString) {           int len = hexString.length()/2;           byte[] result = new byte[len];           for (int i = 0; i < len; i++)               result[i] = Integer.valueOf(hexString.substring(2*i, 2*i+2), 16).byteValue();           return result;       }         public static String toHex(byte[] buf) {           if (buf == null)               return "";           StringBuffer result = new StringBuffer(2*buf.length);           for (int i = 0; i < buf.length; i++) {               appendHex(result, buf[i]);           }           return result.toString();       }       private final static String HEX = "0123456789ABCDEF";       private static void appendHex(StringBuffer sb, byte b) {           sb.append(HEX.charAt((b>>4)&0x0f)).append(HEX.charAt(b&0x0f));       }   }

TestAES.java

package com.test;import android.app.Activity;import android.os.Bundle;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;import android.widget.EditText;import android.widget.TextView;public class TestAES extends Activity implements OnClickListener {private TextView tvTip = null;private EditText etKey = null;private EditText etStr = null;private Button btnEncrypt = null;private Button btnDecrypt = null;//String src = null;String key = null;String dest = null;/** Called when the activity is first created. */@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.main);tvTip = (TextView) findViewById(R.id.tvTip);etKey = (EditText) findViewById(R.id.etKey);etStr = (EditText) findViewById(R.id.etStr);btnEncrypt = (Button) findViewById(R.id.btnEncrypt);btnEncrypt.setOnClickListener(this);btnDecrypt = (Button) findViewById(R.id.btnDecrypt);btnDecrypt.setOnClickListener(this);btnEncrypt.setEnabled(true);btnDecrypt.setEnabled(false);}@Overridepublic void onClick(View v) {// TODO Auto-generated method stubif (v == btnEncrypt) {src = etStr.getText().toString().trim();key = etKey.getText().toString().trim();if (!src.equals("") && !key.equals("")) {try {dest = AESCipher.encrypt(key, src);tvTip.setText("Encrypted:");etStr.setText(dest);btnEncrypt.setEnabled(false);btnDecrypt.setEnabled(true);} catch (Exception e) {// TODO Auto-generated catch blocke.printStackTrace();}}} else if (v == btnDecrypt) {src = etStr.getText().toString().trim();key = etKey.getText().toString().trim();if (!src.equals("") && !key.equals("")) {try {dest = AESCipher.decrypt(key, src);tvTip.setText("Decrypted:");etStr.setText(dest);btnDecrypt.setEnabled(false);btnEncrypt.setEnabled(true);} catch (Exception e) {// TODO Auto-generated catch blocke.printStackTrace();}}else{tvTip.setText("Source:");btnDecrypt.setEnabled(false);btnEncrypt.setEnabled(true);}}}}

main.xml

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="fill_parent"    android:layout_height="fill_parent"    android:orientation="vertical" >    <LinearLayout        android:layout_width="fill_parent"        android:layout_height="wrap_content"        android:orientation="vertical" >        <TextView            android:layout_width="100dp"            android:layout_height="wrap_content"            android:text="Key：" />        <EditText            android:id="@+id/etKey"            android:layout_width="200dp"            android:layout_height="40dp"            android:maxLength="32"            android:hint="Input the key" />    </LinearLayout>    <LinearLayout        android:layout_width="fill_parent"        android:layout_height="wrap_content"        android:orientation="vertical" >        <TextView            android:id="@+id/tvTip"            android:layout_width="100dp"            android:layout_height="wrap_content"            android:text="Source:" />        <EditText            android:id="@+id/etStr"            android:layout_width="400dp"            android:layout_height="200dp"            android:hint="Input the source"            android:inputType="textMultiLine"            android:maxLength="4096"            android:maxLines="100"            android:scrollHorizontally="false" />    </LinearLayout>    <LinearLayout        android:layout_width="fill_parent"        android:layout_height="wrap_content"        android:orientation="horizontal" >        <Button            android:id="@+id/btnEncrypt"            android:layout_width="120dp"            android:layout_height="50dp"            android:text="加密字符串" />        <Button            android:id="@+id/btnDecrypt"            android:layout_width="120dp"            android:layout_height="50dp"            android:text="解密字符串" />            </LinearLayout></LinearLayout>

 源码：http://download.csdn.net/detail/xinzheng_wang/5639611