安卓渗透第三弹-Apk反编译分析加密编写自动化解密脚本

package APP;//import android.util.Base64;  
import java.net.URLEncoder;  
import java.nio.charset.StandardCharsets;  
import java.security.MessageDigest;  
import java.util.*;  
import java.util.stream.Collectors;  
import javax.crypto.Cipher;  
import javax.crypto.SecretKey;  
import javax.crypto.SecretKeyFactory;  
import javax.crypto.spec.DESKeySpec;  
import javax.crypto.spec.IvParameterSpec;  
  
/* loaded from: classes.dex */  
public class DuDu {  
    Cipher deCipher;  
    Cipher enCipher;  
  
    public DuDu(String key, String iv) throws Exception {  
        if (key == null) {  
            throw new NullPointerException("Parameter is null!");  
        }  
        InitCipher(key.getBytes(), iv.getBytes());  
    }  
  
    private void InitCipher(byte[] secKey, byte[] secIv) throws Exception {  
        MessageDigest md = MessageDigest.getInstance("MD5");  
        md.update(secKey);  
        DESKeySpec dsk = new DESKeySpec(md.digest());  
        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");  
        SecretKey key = keyFactory.generateSecret(dsk);  
        IvParameterSpec iv = new IvParameterSpec(secIv);  
        this.enCipher = Cipher.getInstance("DES/CBC/PKCS5Padding");  
        this.deCipher = Cipher.getInstance("DES/CBC/PKCS5Padding");  
        this.enCipher.init(1, key, iv);  
        this.deCipher.init(2, key, iv);  
    }  
  
    public String encrypt64(byte[] data) throws Exception {  
        byte[] encryptedBytes = this.enCipher.doFinal(data);  
        return Base64.getEncoder().encodeToString(encryptedBytes);  
    }  
  
    public byte[] decrypt64(String data) throws Exception {  
        return this.deCipher.doFinal(Base64.getDecoder().decode(data));  
    }  
  
    public String sign(String data) throws Exception {  
        String append = "sdlkjsdljf0j2fsjk";  
  
        // 将 JSON 字符串转换为 Map        Map<String, String> paramMap = Arrays.stream(data.replace("{", "").replace("}", "").split(","))  
                .map(pair -> pair.split(":"))  
                .collect(Collectors.toMap(  
                        kv -> kv[0].trim().replace("\"", ""),  
                        kv -> kv[1].trim().replace("\"", "")  
                ));  
  
        // 对 Map 中的键进行排序  
        List<String> keys = new ArrayList<>(paramMap.keySet());  
        Collections.sort(keys);  
  
        // 拼接参数字符串  
        String paramStr = keys.stream()  
                .filter(key -> !"sign".equals(key))  
                .map(key -> {  
                    return key + "=" + URLEncoder.encode(paramMap.get(key), StandardCharsets.UTF_8);  
                })  
                .collect(Collectors.joining("&")) + "&key=" + URLEncoder.encode(append, StandardCharsets.UTF_8);  
  
        System.out.println("sign明文：" + paramStr);  
        // 对拼接后的参数字符串进行 MD5 加密  
        MessageDigest md = MessageDigest.getInstance("MD5");  
        byte[] digest = md.digest(paramStr.getBytes(StandardCharsets.UTF_8));  
        StringBuilder hexString = new StringBuilder();  
  
        for (byte b : digest) {  
            String hex = Integer.toHexString(0xFF & b);  
            if (hex.length() == 1) {  
                hexString.append('0');  
            }  
            hexString.append(hex);  
        }  
  
        return hexString.toString().toUpperCase();  
    }  
    public static void main(String[] args) throws Exception {  
        DuDu du = new DuDu("65102933","32028092");  
          
        String enc = "";  
        String decryptedString = new String(du.decrypt64(enc));  
        System.out.println("明文：" + decryptedString);  
  
        System.out.println("sign密文:" + du.sign(decryptedString));  
    }  
}