新-sec6-lesson6-平头哥框架hook实战(一个通用的Java层加密算法hook程序) | 关于[B@

package com.sam.myapplicationcj;

import android.util.Log;

import com.virjar.ratel.api.rposed.IRposedHookLoadPackage;
import com.virjar.ratel.api.rposed.RC_MethodHook;
import com.virjar.ratel.api.rposed.RposedHelpers;
import com.virjar.ratel.api.rposed.callbacks.RC_LoadPackage;

import java.math.BigInteger;
import java.security.MessageDigest;

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

public class HookCryptoEntry implements IRposedHookLoadPackage {
    private static final String TAG = "yuanrenxue->";

    @Override
    public void handleLoadPackage(RC_LoadPackage.LoadPackageParam lpparam) throws Throwable {
        if("com.yuanrenxue.course6".equals(lpparam.packageName)){
            Log.d(TAG, "handleLoadPackage: hook success");

            // 想hook这个：new SecretKeySpec(key.getBytes(),"AES");这里用的是findAndHookConstructor因为new ... 就是一个
            // 实例化的过程，所以需要hook的是构造方法而不是普通方法
            RposedHelpers.findAndHookConstructor(SecretKeySpec.class, byte[].class, String.class, new RC_MethodHook() {
                @Override
                protected void afterHookedMethod(MethodHookParam param) throws Throwable {
                    super.afterHookedMethod(param);
                    Log.d(TAG, String.format("SecretKeySpec(%s,%s))",new String((byte[]) param.args[0]),param.args[1]));
                }
            });

            // hook iv:new IvParameterSpec(iv.getBytes());
            RposedHelpers.findAndHookConstructor(IvParameterSpec.class, byte[].class, new RC_MethodHook() {
                @Override
                protected void afterHookedMethod(MethodHookParam param) throws Throwable {
                    super.afterHookedMethod(param);
                    Log.d(TAG, String.format("IvParameterSpec(%s)",new String((byte[]) param.args[0])));
                }
            });

            // hook 采用了什么加密算法:Cipher.getInstance("AES/CBC/PKCS5Padding")
            RposedHelpers.findAndHookMethod(Cipher.class, "getInstance", String.class, new RC_MethodHook() {
                @Override
                protected void afterHookedMethod(MethodHookParam param) throws Throwable {
                    super.afterHookedMethod(param);
                    Log.d(TAG, "发现使用如下加密算法: " + param.args[0]);
                }
            });

            // hook 加密解密过程：cipher.doFinal(content.getBytes());
            RposedHelpers.findAndHookMethod(Cipher.class, "doFinal", byte[].class, new RC_MethodHook() {
                @Override
                protected void afterHookedMethod(MethodHookParam param) throws Throwable {
                    super.afterHookedMethod(param);
                    // 对于加密来说：入参（明文），返回值（密文）
                    // 对于解密来说：入参（密文），返回值（明文） 可以通过这来判断在加密还是在解密
                    // 加密的返回值因为是随机的字节，所以打印出来很可能是鬼画符一样的东西�7sZ������O��像这种，是正常的
                    Log.d(TAG, String.format("入参为：%s,返回值为：%s",new String((byte[])param.args[0]),new String((byte[])param.getResult())));
                }
            });

            // hook采用了哪种哈希函数（摘要算法） MessageDigest.getInstance("MD5");
            RposedHelpers.findAndHookMethod(MessageDigest.class, "getInstance", String.class, new RC_MethodHook() {
                @Override
                protected void afterHookedMethod(MethodHookParam param) throws Throwable {
                    super.afterHookedMethod(param);
                    Log.d(TAG, "发现使用如下哈希函数: " + param.args[0]);
                }
            });

            // 对于摘要内容的hook
            // 1. md.digest(content.getBytes());
            RposedHelpers.findAndHookMethod(MessageDigest.class, "digest", byte[].class, new RC_MethodHook() {
                @Override
                protected void afterHookedMethod(MethodHookParam param) throws Throwable {
                    super.afterHookedMethod(param);
                    Log.d(TAG, "消息内容为: " + new String((byte[]) param.args[0]));
                    Log.d(TAG, "摘要结果为: " + new String((byte[]) param.getResult()));
                    Log.d(TAG, "摘要结果为: " + new BigInteger(1, (byte[]) param.getResult()).toString(16));
                }
            });

            // 2. md.update(content.getBytes());
            RposedHelpers.findAndHookMethod(MessageDigest.class, "update", byte[].class, new RC_MethodHook() {
                @Override
                protected void afterHookedMethod(MethodHookParam param) throws Throwable {
                    super.afterHookedMethod(param);
                    Log.d(TAG, "2.消息内容为: " + new String((byte[]) param.args[0]));
                }
            });

            RposedHelpers.findAndHookMethod(MessageDigest.class, "digest",new RC_MethodHook() {
                @Override
                protected void afterHookedMethod(MethodHookParam param) throws Throwable {
                    super.afterHookedMethod(param);
                    Log.d(TAG, "2.摘要结果为: " + new BigInteger(1, (byte[]) param.getResult()).toString(16));
                }
            });

        }
    }
}

Object 默认的toString 返回的内容
是从内存地址计算出来的一个数值
没有什么实际意义
可以作为对象的唯一ID

String  str = "虎虎生威";
byte[] sb = str.getBytes();
System.out.println(Arrays.toString(sb));
System.out.println("------------");
System.out.println(new String(sb));

System.out.println("------------");
byte[] t={-24, -103, -114, -24, -103, -114, -25, -108, -97, -27, -88, -127};
String str1= new String (t);
System.out.println(str1);