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

from:// http://blog.csdn.net/xinzheng_wang/article/details/9159969

分类：Android 2013-06-24 11:25 328人阅读评论(3) 收藏举报

　　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

[java] view plain copy

packagecom.test;
importjava.security.SecureRandom;
importjavax.crypto.Cipher;
importjavax.crypto.KeyGenerator;
importjavax.crypto.SecretKey;
importjavax.crypto.spec.SecretKeySpec;
publicclassAESCipher{
publicstaticStringencrypt(Stringkey,Stringsrc)throwsException{
byte[]rawKey=getRawKey(key.getBytes());
byte[]result=encrypt(rawKey,src.getBytes());
returntoHex(result);
}
publicstaticStringdecrypt(Stringkey,Stringencrypted)throwsException{
byte[]rawKey=getRawKey(key.getBytes());
byte[]enc=toByte(encrypted);
byte[]result=decrypt(rawKey,enc);
returnnewString(result);
}
privatestaticbyte[]getRawKey(byte[]seed)throwsException{
KeyGeneratorkgen=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
SecureRandomsr=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);//256bitsor128bits,192bits
SecretKeyskey=kgen.generateKey();
byte[]raw=skey.getEncoded();
returnraw;
}
privatestaticbyte[]encrypt(byte[]key,byte[]src)throwsException{
SecretKeySpecskeySpec=newSecretKeySpec(key,"AES");
Ciphercipher=Cipher.getInstance("AES");
cipher.init(Cipher.ENCRYPT_MODE,skeySpec);
byte[]encrypted=cipher.doFinal(src);
returnencrypted;
}
privatestaticbyte[]decrypt(byte[]key,byte[]encrypted)throwsException{
SecretKeySpecskeySpec=newSecretKeySpec(key,"AES");
Ciphercipher=Cipher.getInstance("AES");
cipher.init(Cipher.DECRYPT_MODE,skeySpec);
byte[]decrypted=cipher.doFinal(encrypted);
returndecrypted;
}
publicstaticStringtoHex(Stringtxt){
returntoHex(txt.getBytes());
}
publicstaticStringfromHex(Stringhex){
returnnewString(toByte(hex));
}
publicstaticbyte[]toByte(StringhexString){
intlen=hexString.length()/2;
byte[]result=newbyte[len];
for(inti=0;i<len;i++)
result[i]=Integer.valueOf(hexString.substring(2*i,2*i+2),16).byteValue();
returnresult;
}
publicstaticStringtoHex(byte[]buf){
if(buf==null)
return"";
StringBufferresult=newStringBuffer(2*buf.length);
for(inti=0;i<buf.length;i++){
appendHex(result,buf[i]);
}
returnresult.toString();
}
privatefinalstaticStringHEX="0123456789ABCDEF";
privatestaticvoidappendHex(StringBuffersb,byteb){
sb.append(HEX.charAt((b>>4)&0x0f)).append(HEX.charAt(b&0x0f));
}
}

TestAES.java

[java] view plain copy

packagecom.test;
importandroid.app.Activity;
importandroid.os.Bundle;
importandroid.view.View;
importandroid.view.View.OnClickListener;
importandroid.widget.Button;
importandroid.widget.EditText;
importandroid.widget.TextView;
publicclassTestAESextendsActivityimplementsOnClickListener{
privateTextViewtvTip=null;
privateEditTextetKey=null;
privateEditTextetStr=null;
privateButtonbtnEncrypt=null;
privateButtonbtnDecrypt=null;
//
Stringsrc=null;
Stringkey=null;
Stringdest=null;
/**Calledwhentheactivityisfirstcreated.*/
@Override
publicvoidonCreate(BundlesavedInstanceState){
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);
}
@Override
publicvoidonClick(Viewv){
//TODOAuto-generatedmethodstub
if(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(Exceptione){
//TODOAuto-generatedcatchblock
e.printStackTrace();
}
}
}elseif(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(Exceptione){
//TODOAuto-generatedcatchblock
e.printStackTrace();
}
}else{
tvTip.setText("Source:");
btnDecrypt.setEnabled(false);
btnEncrypt.setEnabled(true);
}
}
}
}

main.xml

[html] view plain copy

<?xmlversion="1.0"encoding="utf-8"?>
<LinearLayoutxmlns: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="Inputthekey"/>
</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="Inputthesource"
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>

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

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

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