Android AES加密解密

import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;

/**
* AES加密解密工具
*
* @author yangle
*/
public class AESUtils {

/**
* AES加密
*
* @param data
*            将要加密的内容
* @param key
*            密钥
* @return 已经加密的内容
*/
public static byte[] encrypt(byte[] data, byte[] key) {
//不足16字节，补齐内容为差值
int len = 16 - data.length % 16;
for (int i = 0; i < len; i++) {
byte[] bytes = { (byte) len };
data = ArrayUtils.concat(data, bytes);
}
try {
SecretKeySpec skeySpec = new SecretKeySpec(key, "AES");
Cipher cipher = Cipher.getInstance("AES/ECB/NoPadding");
cipher.init(Cipher.ENCRYPT_MODE, skeySpec);
return cipher.doFinal(data);
} catch (Exception e) {
e.printStackTrace();
}
return new byte[] {};
}

/**
* AES解密
*
* @param data
*            将要解密的内容
* @param key
*            密钥
* @return 已经解密的内容
*/
public static byte[] decrypt(byte[] data, byte[] key) {
data = ArrayUtils.noPadding(data, -1);
try {
SecretKeySpec skeySpec = new SecretKeySpec(key, "AES");
Cipher cipher = Cipher.getInstance("AES/ECB/NoPadding");
cipher.init(Cipher.DECRYPT_MODE, skeySpec);
byte[] decryptData = cipher.doFinal(data);
int len = 2 + ByteUtils.byteToInt(decryptData[4]) + 3;
return ArrayUtils.noPadding(decryptData, len);
} catch (Exception e) {
e.printStackTrace();
}
return new byte[] {};
}
}

/**
* 数组工具
*
* @author yangle
*/
public class ArrayUtils {

/**
* 合并数组
*
* @param firstArray
*            第一个数组
* @param secondArray
*            第二个数组
* @return 合并后的数组
*/
public static byte[] concat(byte[] firstArray, byte[] secondArray) {
if (firstArray == null || secondArray == null) {
return null;
}
byte[] bytes = new byte[firstArray.length + secondArray.length];
System.arraycopy(firstArray, 0, bytes, 0, firstArray.length);
System.arraycopy(secondArray, 0, bytes, firstArray.length,
secondArray.length);
return bytes;
}

/**
* 去除数组中的补齐
*
* @param paddingBytes
*            源数组
* @param dataLength
*            去除补齐后的数据长度
* @return 去除补齐后的数组
*/
public static byte[] noPadding(byte[] paddingBytes, int dataLength) {
if (paddingBytes == null) {
return null;
}

byte[] noPaddingBytes = null;
if (dataLength > 0) {
if (paddingBytes.length > dataLength) {
noPaddingBytes = new byte[dataLength];
System.arraycopy(paddingBytes, 0, noPaddingBytes, 0, dataLength);
} else {
noPaddingBytes = paddingBytes;
}
} else {
int index = paddingIndex(paddingBytes);
if (index > 0) {
noPaddingBytes = new byte[index];
System.arraycopy(paddingBytes, 0, noPaddingBytes, 0, index);
}
}

return noPaddingBytes;
}

/**
* 获取补齐的位置
*
* @param paddingBytes
*            源数组
* @return 补齐的位置
*/
private static int paddingIndex(byte[] paddingBytes) {
for (int i = paddingBytes.length - 1; i >= 0; i--) {
if (paddingBytes[i] != 0) {
return i + 1;
}
}
return -1;
}
}