using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Security.Cryptography;
using System.Text;
using System.Text.Json.Serialization;
using System.Threading.Tasks;
using System.Windows;
using WechatPCMsgBakTool.Model;
namespace WechatPCMsgBakTool.Helpers
{
public class DecryptionHelper
{
const int IV_SIZE = 16;
const int HMAC_SHA1_SIZE = 20;
const int KEY_SIZE = 32;
const int AES_BLOCK_SIZE = 16;
const int DEFAULT_ITER = 64000;
const int DEFAULT_PAGESIZE = 4096; //4048数据 + 16IV + 20 HMAC + 12
const string SQLITE_HEADER = "SQLite format 3";
public static byte[]? GetWechatKey(bool mem_find_key,string account)
{
Process? process = ProcessHelper.GetProcess("WeChat");
if (process == null)
{
return null;
}
ProcessModule? module = ProcessHelper.FindProcessModule(process.Id, "WeChatWin.dll");
if (module == null)
{
return null;
}
string? version = module.FileVersionInfo.FileVersion;
if (version == null)
{
return null;
}
if (!mem_find_key)
{
List<VersionInfo>? info = null;
string json = File.ReadAllText("version.json");
info = JsonConvert.DeserializeObject<List<VersionInfo>?>(json);
if (info == null)
return null;
if (info.Count == 0)
return null;
VersionInfo? cur = info.Find(x => x.Version == version);
if (cur == null)
return null;
//这里加的是版本偏移量，兼容不同版本把这个加给改了
long baseAddress = (long)module.BaseAddress + cur.BaseAddr;
byte[]? bytes = ProcessHelper.ReadMemoryDate(process.Handle, (IntPtr)baseAddress, 8);
if (bytes != null)
{
IntPtr baseAddress2 = (IntPtr)(((long)bytes[7] << 56) + ((long)bytes[6] << 48) + ((long)bytes[5] << 40) + ((long)bytes[4] << 32) + ((long)bytes[3] << 24) + ((long)bytes[2] << 16) + ((long)bytes[1] << 8) + (long)bytes[0]);
byte[]? twoGet = ProcessHelper.ReadMemoryDate(process.Handle, baseAddress2, 32);
if (twoGet != null)
{
string key = BytesToHex(twoGet);
return twoGet;
}
}
}
else
{
List<int> read = ProcessHelper.FindProcessMemory(process.Handle, module, account);
if(read.Count >= 2)
{
byte[] buffer = new byte[8];
int key_offset = read[1] - 64;
if (ProcessHelper.ReadProcessMemory(process.Handle, module.BaseAddress + key_offset, buffer, buffer.Length, out _))
{
ulong addr = BitConverter.ToUInt64(buffer, 0);
byte[] key_bytes = new byte[32];
if(ProcessHelper.ReadProcessMemory(process.Handle, (IntPtr)addr, key_bytes, key_bytes.Length, out _))
{
return key_bytes;
}
}
}
else
{
MessageBox.Show("搜索不到微信账号，请确认用户名是否正确，如错误请重新新建工作区，务必确认账号是否正确", "错误");
}
}
return null;
}
public static byte[] DecryptDB(byte[] db_file_bytes, byte[] password_bytes)
{
//数据库头16字节是盐值
var salt = db_file_bytes.Take(16).ToArray();
//HMAC验证时用的盐值需要亦或0x3a
byte[] hmac_salt = new byte[16];
for (int i = 0; i < salt.Length; i++)
{
hmac_salt[i] = (byte)(salt[i] ^ 0x3a);
}
//计算保留段长度
int reserved = IV_SIZE;
reserved += HMAC_SHA1_SIZE;
reserved = ((reserved % AES_BLOCK_SIZE) == 0) ? reserved : ((reserved / AES_BLOCK_SIZE) + 1) * AES_BLOCK_SIZE;
//密钥扩展，分别对应AES解密密钥和HMAC验证密钥
byte[] key = new byte[KEY_SIZE];
byte[] hmac_key = new byte[KEY_SIZE];
OpenSSLInterop.PKCS5_PBKDF2_HMAC_SHA1(password_bytes, password_bytes.Length, salt, salt.Length, DEFAULT_ITER, key.Length, key);
OpenSSLInterop.PKCS5_PBKDF2_HMAC_SHA1(key, key.Length, hmac_salt, hmac_salt.Length, 2, hmac_key.Length, hmac_key);
int page_no = 0;
int offset = 16;
Console.WriteLine("开始解密...");
var hmac_sha1 = HMAC.Create("HMACSHA1");
hmac_sha1!.Key = hmac_key;
List<byte> decrypted_file_bytes = new List<byte>();
while (page_no < db_file_bytes.Length / DEFAULT_PAGESIZE)
{
byte[] decryped_page_bytes = new byte[DEFAULT_PAGESIZE];
byte[] going_to_hashed = new byte[DEFAULT_PAGESIZE - reserved - offset + IV_SIZE + 4];
db_file_bytes.Skip((page_no * DEFAULT_PAGESIZE) + offset).Take(DEFAULT_PAGESIZE - reserved - offset + IV_SIZE).ToArray().CopyTo(going_to_hashed, 0);
var page_bytes = BitConverter.GetBytes(page_no + 1);
page_bytes.CopyTo(going_to_hashed, DEFAULT_PAGESIZE - reserved - offset + IV_SIZE);
//计算分页的Hash
var hash_mac_compute = hmac_sha1.ComputeHash(going_to_hashed, 0, going_to_hashed.Count());
//取出分页中存储的Hash
var hash_mac_cached = db_file_bytes.Skip((page_no * DEFAULT_PAGESIZE) + DEFAULT_PAGESIZE - reserved + IV_SIZE).Take(hash_mac_compute.Length).ToArray();
//对比两个Hash
if (!hash_mac_compute.SequenceEqual(hash_mac_cached))
{
Console.WriteLine("Hash错误...");
return decrypted_file_bytes.ToArray();
}
else
{
Console.WriteLine($"解密第[{page_no + 1}]页");
if (page_no == 0)
{
var header_bytes = Encoding.ASCII.GetBytes(SQLITE_HEADER);
header_bytes.CopyTo(decryped_page_bytes, 0);
}
var encrypted_content = db_file_bytes.Skip((page_no * DEFAULT_PAGESIZE) + offset).Take(DEFAULT_PAGESIZE - reserved - offset).ToArray();
var iv = db_file_bytes.Skip((page_no * DEFAULT_PAGESIZE) + (DEFAULT_PAGESIZE - reserved)).Take(16).ToArray();
var decrypted_content = DecryptionHelper.AESDecrypt(encrypted_content, key, iv);
decrypted_content.CopyTo(decryped_page_bytes, offset);
var reserved_bytes = db_file_bytes.Skip((page_no * DEFAULT_PAGESIZE) + DEFAULT_PAGESIZE - reserved).Take(reserved).ToArray();
reserved_bytes.CopyTo(decryped_page_bytes, DEFAULT_PAGESIZE - reserved);
}
page_no++;
offset = 0;
foreach (var item in decryped_page_bytes)
{
decrypted_file_bytes.Add(item);
}
}
return decrypted_file_bytes.ToArray();
}
public static byte[] AESDecrypt(byte[] content, byte[] key, byte[] iv)
{
Aes rijndaelCipher = Aes.Create();
rijndaelCipher.Mode = CipherMode.CBC;
rijndaelCipher.Padding = PaddingMode.None;
rijndaelCipher.KeySize = 256;
rijndaelCipher.BlockSize = 128;
rijndaelCipher.Key = key;
rijndaelCipher.IV = iv;
ICryptoTransform transform = rijndaelCipher.CreateDecryptor();
byte[] plain_bytes = transform.TransformFinalBlock(content, 0, content.Length);
return plain_bytes;
}
private static string BytesToHex(byte[] bytes)
{
return BitConverter.ToString(bytes, 0).Replace("-", string.Empty).ToLower().ToUpper();
}
public static byte[] DecImage(string source)
{
//读取数据
byte[] fileBytes = File.ReadAllBytes(source);
//算差异转换
byte key = GetImgKey(fileBytes);
fileBytes = ConvertData(fileBytes, key);
return fileBytes;
}
public static string CheckFileType(byte[] data)
{
switch (data[0])
{
case 0XFF: //byte[] jpg = new byte[] { 0xFF, 0xD8, 0xFF };
{
if (data[1] == 0xD8 && data[2] == 0xFF)
{
return ".jpg";
}
break;
}
case 0x89: //byte[] png = new byte[] { 0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A };
{
if (data[1] == 0x50 && data[2] == 0x4E && data[7] == 0x0A)
{
return ".png";
}
break;
}
case 0x42: //byte[] bmp = new byte[] { 0x42, 0x4D };
{
if (data[1] == 0X4D)
{
return ".bmp";
}
break;
}
case 0x47: //byte[] gif = new byte[] { 0x47, 0x49, 0x46, 0x38, 0x39(0x37), 0x61 };
{
if (data[1] == 0x49 && data[2] == 0x46 && data[3] == 0x38 && data[5] == 0x61)
{
return ".gif";
}
break;
}
case 0x49: // byte[] tif = new byte[] { 0x49, 0x49, 0x2A, 0x00 };
{
if (data[1] == 0x49 && data[2] == 0x2A && data[3] == 0x00)
{
return ".tif";
}
break;
}
case 0x4D: //byte[] tif = new byte[] { 0x4D, 0x4D, 0x2A, 0x00 };
{
if (data[1] == 0x4D && data[2] == 0x2A && data[3] == 0x00)
{
return ".tif";
}
break;
}
}
return ".dat";
}
private static byte GetImgKey(byte[] fileRaw)
{
byte[] raw = new byte[8];
for (int i = 0; i < 8; i++)
{
raw[i] = fileRaw[i];
}
for (byte key = 0x01; key < 0xFF; key++)
{
byte[] buf = new byte[8];
raw.CopyTo(buf, 0);
if (CheckFileType(ConvertData(buf, key)) != ".dat")
{
return key;
}
}
return 0x00;
}
private static byte[] ConvertData(byte[] data, byte key)
{
for (int i = 0; i < data.Length; i++)
{
data[i] ^= key;
}
return data;
}
public static string SaveDecImage(byte[] fileRaw,string source,string to_dir,string type)
{
FileInfo fileInfo = new FileInfo(source);
string fileName = fileInfo.Name.Substring(0, fileInfo.Name.Length - 4);
string saveFilePath = Path.Combine(to_dir, fileName + type);
using (FileStream fileStream = File.OpenWrite(saveFilePath))
{
fileStream.Write(fileRaw, 0, fileRaw.Length);
fileStream.Flush();
}
return saveFilePath;
}
}
}