Android AES加密算法及其实现

昨天老大叫我看看android加密算法。于是网上找了找，找到了AES加密算法。（当然还有MD5,BASE64什么的/article/4183682.html这篇文章列举了很多，但是基本都是j2se平台的，android平台不一定支持，但是AES算法Android是自带了包的，从官方的http://developer.android.com/reference/javax/crypto/Cipher.html可以看到。

）

AES加密算法是什么？大家可以自己去google，专家级程序员写好包，工程人员会用就行了。

这个例子其实是来自http://www.tutorials-android.com/learn/How_to_encrypt_and_decrypt_strings.rhtml。

src目录主文件：

[java] view
plain copy

package com.qq;

import java.security.SecureRandom;

import javax.crypto.Cipher;

import javax.crypto.KeyGenerator;

import javax.crypto.SecretKey;

import javax.crypto.spec.SecretKeySpec;

import android.app.Activity;

import android.os.Bundle;

import android.util.Log;

public class SimpleCrypto extends Activity {

public static String encrypt(String seed, String cleartext) throws Exception {

byte[] rawKey = getRawKey(seed.getBytes());

byte[] result = encrypt(rawKey, cleartext.getBytes());

return toHex(result);

}

public static String decrypt(String seed, String encrypted) throws Exception {

byte[] rawKey = getRawKey(seed.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");

SecureRandom sr = SecureRandom.getInstance("SHA1PRNG");

sr.setSeed(seed);

kgen.init(128, sr); // 192 and 256 bits may not be available

SecretKey skey = kgen.generateKey();

byte[] raw = skey.getEncoded();

return raw;

}

private static byte[] encrypt(byte[] raw, byte[] clear) throws Exception {

SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");

Cipher cipher = Cipher.getInstance("AES");

cipher.init(Cipher.ENCRYPT_MODE, skeySpec);

byte[] encrypted = cipher.doFinal(clear);

return encrypted;

}

private static byte[] decrypt(byte[] raw, byte[] encrypted) throws Exception {

SecretKeySpec skeySpec = new SecretKeySpec(raw, "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));

}

/** Called when the activity is first created. */

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

String masterPassword = "a";

String originalText = "0123456789";

byte[] text = new byte[]{'0','1','2','3','4','5','6','7','8','9'};

byte[] password = new byte[]{'a'};

try {

String encryptingCode = SimpleCrypto.encrypt(masterPassword,originalText);

// System.out.println("加密结果为 " + encryptingCode);

Log.i("加密结果为 ",encryptingCode);

String decryptingCode = SimpleCrypto.decrypt(masterPassword, encryptingCode);

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();

}

}

}

布局文件main.xml和配置文件AndroidManifest.xml默认就好了。最后结果在Log里面看，利用adb logcat > d:\1.txt定位到D盘的1.txt文件，然后用记事本打开就，查找”加密结果为“就可以看到了：

运行结果（从log日志中看到的）：

I/加密结果为 ( 190): BFB77D8F1E1EE9D5E252926A12659DE8

I/解密结果( 190): 0123456789

转载地址：/article/2506197.html