Android AES加密算法及其实现

        Android AES加密算法及其实现       

        分类：            Android学习2011-07-06 14:2110398人阅读评论(9)收藏举报

加密androidbytestringexception算法

       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http://snowolf.iteye.com/blog/379860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 plaincopyprint?

1. package com.qq; 
2. import java.security.SecureRandom; 
3.  
4. import javax.crypto.Cipher; 
5. import javax.crypto.KeyGenerator; 
6. import javax.crypto.SecretKey; 
7. import javax.crypto.spec.SecretKeySpec; 
8.  
9. import android.app.Activity; 
10. import android.os.Bundle; 
11. import android.util.Log; 
12.  
13. public class SimpleCryptoextends Activity { 
14.      public static String encrypt(String seed, String cleartext)throws Exception {     
15.             byte[] rawKey = getRawKey(seed.getBytes());     
16.             byte[] result = encrypt(rawKey, cleartext.getBytes());     
17.             return toHex(result);     
18.         }     
19.              
20.         public static String decrypt(String seed, String encrypted)throws Exception {     
21.             byte[] rawKey = getRawKey(seed.getBytes());     
22.             byte[] enc = toByte(encrypted);     
23.             byte[] result = decrypt(rawKey, enc);     
24.             return new String(result);     
25.         }     
26.         
27.         private staticbyte[] getRawKey(byte[] seed)throws Exception {     
28.             KeyGenerator kgen = KeyGenerator.getInstance("AES");     
29.             SecureRandom sr = SecureRandom.getInstance("SHA1PRNG");     
30.             sr.setSeed(seed);     
31.             kgen.init(128, sr);// 192 and 256 bits may not be available     
32.             SecretKey skey = kgen.generateKey();     
33.             byte[] raw = skey.getEncoded();     
34.             return raw;     
35.         }     
36.         
37.              
38.         private staticbyte[] encrypt(byte[] raw,byte[] clear) throws Exception {     
39.             SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");     
40.             Cipher cipher = Cipher.getInstance("AES");     
41.             cipher.init(Cipher.ENCRYPT_MODE, skeySpec);     
42.             byte[] encrypted = cipher.doFinal(clear);     
43.             return encrypted;     
44.         }     
45.         
46.         private staticbyte[] decrypt(byte[] raw,byte[] encrypted) throws Exception {     
47.             SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");     
48.             Cipher cipher = Cipher.getInstance("AES");     
49.             cipher.init(Cipher.DECRYPT_MODE, skeySpec);     
50.             byte[] decrypted = cipher.doFinal(encrypted);     
51.             return decrypted;     
52.         }     
53.         
54.         public static String toHex(String txt) {     
55.             return toHex(txt.getBytes());     
56.         }     
57.         public static String fromHex(String hex) {     
58.             return new String(toByte(hex));     
59.         }     
60.              
61.         public staticbyte[] toByte(String hexString) {     
62.             int len = hexString.length()/2;     
63.             byte[] result =new byte[len];     
64.             for (int i =0; i < len; i++)     
65.                 result[i] = Integer.valueOf(hexString.substring(2*i,2*i+2),16).byteValue();     
66.             return result;     
67.         }     
68.         
69.         public static String toHex(byte[] buf) {     
70.             if (buf == null)     
71.                 return "";     
72.             StringBuffer result = new StringBuffer(2*buf.length);     
73.             for (int i =0; i < buf.length; i++) {     
74.                 appendHex(result, buf[i]);     
75.             }     
76.             return result.toString();     
77.         }     
78.         private finalstatic String HEX = "0123456789ABCDEF";     
79.         private staticvoid appendHex(StringBuffer sb, byte b) {     
80.             sb.append(HEX.charAt((b>>4)&0x0f)).append(HEX.charAt(b&0x0f));     
81.         }  
82.     /** Called when the activity is first created. */ 
83.     @Override 
84.     public void onCreate(Bundle savedInstanceState) { 
85.         super.onCreate(savedInstanceState); 
86.         setContentView(R.layout.main); 
87.         String masterPassword = "a"; 
88.         String originalText = "0123456789"; 
89.         byte[] text = new byte[]{'0','1','2','3','4','5','6','7','8','9'}; 
90.         byte[] password = newbyte[]{'a'}; 
91.         try { 
92.             String encryptingCode = SimpleCrypto.encrypt(masterPassword,originalText); 
93. //          System.out.println("加密结果为 " + encryptingCode); 
94.             Log.i("加密结果为 ",encryptingCode); 
95.             String decryptingCode = SimpleCrypto.decrypt(masterPassword, encryptingCode); 
96.             System.out.println("解密结果为 " + decryptingCode); 
97.             Log.i("解密结果",decryptingCode); 
98.            } catch (Exception e) { 
99.             // TODO Auto-generated catch block 
100.             e.printStackTrace(); 
101.     } 
102.     } 
103. } 

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