GARbro-mirror/ArcFormats/DxLib/DxKey.cs
2024-07-14 20:59:18 +02:00

211 lines
6.7 KiB
C#

//! \file DxKey.cs
//! \date 2019 Feb 01
//! \brief DxLib archive encryption classes.
//
// Copyright (C) 2019 by morkt
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to
// deal in the Software without restriction, including without limitation the
// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
// sell copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
// IN THE SOFTWARE.
//
using System;
using System.Linq;
using System.Security.Cryptography;
using System.Xml.Linq;
using GameRes.Utility;
namespace GameRes.Formats.DxLib
{
public interface IDxKey
{
string Password { get; }
byte[] Key { get; }
byte[] GetEntryKey (string name);
}
[Serializable]
public class DxKey : IDxKey
{
string m_password;
byte[] m_key;
public DxKey () : this (string.Empty)
{
}
public DxKey (string password)
{
Password = password;
}
public DxKey (byte[] key)
{
Key = key;
}
public string Password
{
get { return m_password; }
set { m_password = value; m_key = null; }
}
public byte[] Key
{
get { return m_key ?? (m_key = CreateKey (m_password)); }
set { m_key = value; m_password = RestoreKey (m_key); }
}
public virtual byte[] GetEntryKey (string name)
{
return Key;
}
protected virtual byte[] CreateKey (string keyword)
{
byte[] key;
if (string.IsNullOrEmpty (keyword))
{
key = Enumerable.Repeat<byte> (0xAA, 12).ToArray();
}
else
{
key = new byte[12];
int char_count = Math.Min (keyword.Length, 12);
int length = Encodings.cp932.GetBytes (keyword, 0, char_count, key, 0);
if (length < 12)
Binary.CopyOverlapped (key, 0, length, 12-length);
}
key[0] ^= 0xFF;
key[1] = Binary.RotByteR (key[1], 4);
key[2] ^= 0x8A;
key[3] = (byte)~Binary.RotByteR (key[3], 4);
key[4] ^= 0xFF;
key[5] ^= 0xAC;
key[6] ^= 0xFF;
key[7] = (byte)~Binary.RotByteR (key[7], 3);
key[8] = Binary.RotByteL (key[8], 3);
key[9] ^= 0x7F;
key[10] = (byte)(Binary.RotByteR (key[10], 4) ^ 0xD6);
key[11] ^= 0xCC;
return key;
}
protected virtual string RestoreKey (byte[] key)
{
var bin = key.Clone() as byte[];
bin[0] ^= 0xFF;
bin[1] = Binary.RotByteL (bin[1], 4);
bin[2] ^= 0x8A;
bin[3] = Binary.RotByteL ((byte)~bin[3], 4);
bin[4] ^= 0xFF;
bin[5] ^= 0xAC;
bin[6] ^= 0xFF;
bin[7] = Binary.RotByteL ((byte)~bin[7], 3);
bin[8] = Binary.RotByteR (bin[8], 3);
bin[9] ^= 0x7F;
bin[10] = Binary.RotByteL ((byte)(bin[10] ^ 0xD6), 4);
bin[11] ^= 0xCC;
return Encodings.cp932.GetString (bin);
}
}
[Serializable]
public class DxKey7 : DxKey
{
public DxKey7 (string password) : base (password ?? "DXARC")
{
}
public override byte[] GetEntryKey (string name)
{
var password = this.Password;
var path = name.Split ('\\', '/');
password += string.Join ("", path.Reverse().Select (n => n.ToUpperInvariant()));
return CreateKey (password);
}
protected override byte[] CreateKey (string keyword)
{
using (var sha = SHA256.Create())
{
var bytes = Encodings.cp932.GetBytes (keyword);
return sha.ComputeHash (bytes);
}
}
protected override string RestoreKey (byte[] key)
{
throw new NotSupportedException ("SHA-256 key cannot be restored.");
}
}
[Serializable]
public class DxKey8 : DxKey
{
public DxKey8(string password) : base(password ?? "DXARC")
{
}
public override byte[] GetEntryKey(string name)
{
var password = this.Password;
var path = name.Split('\\', '/');
password += string.Join("", path.Reverse().Select(n => n.ToUpperInvariant()));
return CreateKey(password);
}
protected override byte[] CreateKey(string keyword)
{
//from DxArchive.cpp
//first check if the keyword is too short
if (keyword.Length < 4)
{
keyword += "DXARC";
}
string oddString, evenString;
byte[] key = new byte[7];
oddString = string.Concat(keyword.Where((c, i) => i % 2 == 0));
evenString = string.Concat(keyword.Where((c, i) => (i+1) % 2 == 0));
UInt32 crc_0, crc_1;
crc_0 = Crc32.Compute(Encodings.ASCII.GetBytes(oddString), 0, oddString.Length);
crc_1 = Crc32.Compute(Encodings.ASCII.GetBytes(evenString), 0, evenString.Length);
byte[] crc_0_Bytes = BitConverter.GetBytes(crc_0),crc_1_Bytes=BitConverter.GetBytes(crc_1);
key[0] = crc_0_Bytes[0];
key[1] = crc_0_Bytes[1];
key[2] = crc_0_Bytes[2];
key[3] = crc_0_Bytes[3];
key[4] = crc_1_Bytes[0];
key[5] = crc_1_Bytes[1];
key[6] = crc_1_Bytes[2];
return key;
/*
using (var sha = SHA256.Create())
{
var bytes = Encodings.cp932.GetBytes(keyword);
return sha.ComputeHash(bytes);
} */
}
protected override string RestoreKey(byte[] key)
{
throw new NotSupportedException("CRC key cannot be restored.");
}
}
}