Android网络数据传输安全——AES加密解密（ECB模式）

import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.text.TextUtils;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

import tsou.com.encryption.R;
import tsou.com.encryption.aesecb.AESUtils;

/**
 * ECB模式自设定秘钥
 */
public class AESECBActivity extends AppCompatActivity implements View.OnClickListener {

    private EditText encryptionContext;
    private Button encryption;
    private TextView tvEncryption;
    private Button decode;
    private TextView tvDecode;
    private Activity mActivity;
    private Context mContext;
    private String key = "huangxiaoguo1234";//必须16位
    private byte[] encrypt;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_aes);
        mActivity = this;
        mContext = this;
        encryptionContext = (EditText) findViewById(R.id.et_encryption_context);
        encryption = (Button) findViewById(R.id.btn_encryption);
        tvEncryption = (TextView) findViewById(R.id.tv_encryption);
        decode = (Button) findViewById(R.id.btn_decode);
        tvDecode = (TextView) findViewById(R.id.tv_decode);
        initListener();
    }

    private void initListener() {
        encryption.setOnClickListener(this);
        decode.setOnClickListener(this);
    }

    @Override
    public void onClick(View view) {
        switch (view.getId()) {
            case R.id.btn_encryption://加密
                String encryptionString = encryptionContext.getText().toString().trim();
                if (TextUtils.isEmpty(encryptionString)) {
                    Toast.makeText(mContext, "请输入加密内容", Toast.LENGTH_SHORT).show();
                    return;
                }
                encrypt = AESUtils.encrypt(encryptionString.getBytes(), key.getBytes());
                tvEncryption.setText(new String(encrypt));
                break;
            case R.id.btn_decode://解密
                String decodeString = tvEncryption.getText().toString().trim();
                if (TextUtils.isEmpty(decodeString)) {
                    Toast.makeText(mContext, "请先加密", Toast.LENGTH_SHORT).show();
                    return;
                }
                byte[] decrypt = AESUtils.decrypt(encrypt, key.getBytes());
                tvDecode.setText(new String(decrypt));
                break;
        }
    }
}

package tsou.com.encryption.aesecb;

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

/**
 * AES加密解密工具 
 *  
 * @author huangxiaoguo
 */  
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[] {};  
    }  

package tsou.com.encryption.aesecb;

/**
 * 数组工具 
 *  
 * @author huangxiaoguo
 */  
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;  
    }  
}

package tsou.com.encryption.aesecb;

public class ByteUtils {
    public static int byteToInt(byte b) {
        return (b) & 0xff;
    }
}