AES Android 加密

package cn.com.smartpay.app.http;

import java.security.SecureRandom;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;

/**
* @author carlos carlosk@163.com
* @version 创建时间：2012-5-17 上午9:48:35 类说明
*/

public class AESUtils {
public static final String TAG = "AESUtils";

public static String encrypt(String seed, String clearText) {
// Log.d(TAG, "加密前的seed=" + seed + ",内容为:" + clearText);
byte[] result = null;
try {
byte[] rawkey = getRawKey(seed.getBytes());
result = encrypt(rawkey, clearText.getBytes());
} catch (Exception e) {
e.printStackTrace();
}
String content = toHex(result);
// Log.d(TAG, "加密后的内容为:" + content);
return content;

}

public static String decrypt(String seed, String encrypted) {
// Log.d(TAG, "解密前的seed=" + seed + ",内容为:" + encrypted);
byte[] rawKey;
try {
rawKey = getRawKey(seed.getBytes());
byte[] enc = toByte(encrypted);
byte[] result = decrypt(rawKey, enc);
String coentn = new String(result);
// Log.d(TAG, "解密后的内容为:" + coentn);
return coentn;
} catch (Exception e) {
e.printStackTrace();
return null;
}

}

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);
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 cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
cipher.init(Cipher.ENCRYPT_MODE, skeySpec, new IvParameterSpec(
new byte[cipher.getBlockSize()]));
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 cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
cipher.init(Cipher.DECRYPT_MODE, skeySpec, new IvParameterSpec(
new byte[cipher.getBlockSize()]));
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 static void appendHex(StringBuffer sb, byte b) {
final String HEX = "0123456789ABCDEF";
sb.append(HEX.charAt((b >> 4) & 0x0f)).append(HEX.charAt(b & 0x0f));
}
}

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