Android加密与解密

2018-12-14 | 阅读：次

加密/解密对称加密:只有一把密钥,如果密钥暴露,文件就会被暴露

des: Data Encryption Standard

aes: Advanced Encryption Standard

特点:

加密速度比较快.可以加密比较大的文件
密码可以自己指定
非对称加密:有两把钥匙(密钥对),公钥和私钥,公钥的话给别人.私钥自己保存;

RSA

特点:加密速度比慢一些,但是安全系数比较高
秘钥对的话需要程序生成.不能我们自己定义

1.加密/解密:公钥加密–>私钥解密

public static byte[] encryptByPublicKey(byte[] data, String publicKey)//公钥加密

public static byte[] decryptByPrivateKey(byte[] encryptedData, String privateKey)//私钥解密

2.加密/解密:私钥加密–>公钥解密

public static byte[] encryptByPrivateKey(byte[] data, String privateKey)//私钥加密

public static byte[] decryptByPublicKey(byte[] encryptedData, String publicKey)//公钥解密

3.数字签名:私钥签名–>公钥校验,确定数据来源的不可否认性,确定所属关系–>其实就是确定privatekey在哪里.

签名:public static String sign(byte[] data, String privateKey)//只能使用私钥进行签名

校验:public static boolean verify(byte[] data, String publicKey, String sign)

公钥互换:两个人,两个机构,就是说两个密钥对的持有者相互的置换公钥

package com.cllstudy.aesdesrsa;
 
import java.util.Map;
import com.billy.androidutils.utils.encrypt.aes.AesHelper;
import com.billy.androidutils.utils.encrypt.des.DesHelper;
import com.billy.androidutils.utils.encrypt.rsa.RsaHelper;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;
 
public class MainActivity extends Activity {
private TextView textView;
private String context = "Sunshine always comes after the rain";
private String password = "11223344556677889900";
private boolean isAes = false;
private boolean isDes = false;
private boolean isRsa = false;
private String privateKey;
private String publicKey;
private String aesEncrypt;
private String encrypt;
private byte[] encryptByPrivateKey;
 
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    textView = (TextView) findViewById(R.id.textView);
    try {
        Map<String, Object> genKeyPair = RsaHelper.genKeyPair();
        privateKey = RsaHelper.getPrivateKey(genKeyPair);
        publicKey = RsaHelper.getPublicKey(genKeyPair);
    } catch (Exception e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
 
}
 
/**
 * aes加密解密
 *
 * @param view
 */
public void aes(View view) {
    if (!isAes) {
        // 加密
        aesEncrypt = AesHelper.encrypt(context, password);
        textView.setText(aesEncrypt);
    } else {
        String aesDecrypt = AesHelper.decrypt(aesEncrypt, password);
        textView.setText(aesDecrypt);
    }
    isAes = !isAes;
}
 
/**
 * des加密解密
 *
 * @param view
 */
public void des(View view) {
    try {
        if (!isDes) {
            // 加密
            encrypt = DesHelper.encrypt(context, password);
            textView.setText(encrypt);
        } else {
            // 解密
            String decrypt = DesHelper.decrypt(encrypt, password);
            textView.setText(decrypt);
        }
        isDes = !isDes;
 
    } catch (Exception e) {
        // TODO: handle exception
    }
}
 
/**
 * rsa加密解密
 *
 * @param view
 */
public void rsa(View view) {
    try {
        if (!isRsa) {
            // 加密
            encryptByPrivateKey = RsaHelper.encryptByPrivateKey(
                    context.getBytes(), privateKey);
            String encode = RsaHelper.encode(encryptByPrivateKey);
            textView.setText(encode);
        } else {
            // 解密
            byte[] decryptByPublicKey = RsaHelper.decryptByPublicKey(
                    encryptByPrivateKey, publicKey);
            textView.setText(new String(decryptByPublicKey));
        }
        isRsa = !isRsa;
    } catch (Exception e) {
        // TODO: handle exception
    }
}
 
}