Android加密篇 AES

大家好，又见面了，我是你们的朋友全栈君。

AES加密是一种高级加密标准，是一种区块加密标准。它是一个对称密码，就是说加密和解密用相同的密钥。WPA/WPA2经常用的加密方式就是AES加密算法。

import java.io.UnsupportedEncodingException;
import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;
public class AESUtils3 { 

/* 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;
}
}