chizui/YarikStudio
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

- [Core] Added new entries.

Browse Source
This commit is contained in:
Razmoth
2023-12-30 14:38:43 +04:00
parent c51c2b81d8
commit 6cdcc2c292
5 changed files with 103 additions and 16 deletions
Download Patch File Download Diff File Expand all files Collapse all files

27
AssetStudio/Crypto/NetEaseUtils.cs
View File

@@ -9,29 +9,38 @@ namespace AssetStudio
public static class NetEaseUtils
{
private static readonly byte[] Signature = new byte[] { 0xEE, 0xDD };
public static void Decrypt(Span<byte> bytes)
public static void DecryptWithHeader(Span<byte> bytes)
{
var (encryptedOffset, encryptedSize) = ReadHeader(bytes);
var encrypted = bytes.Slice(encryptedOffset, encryptedSize);
Decrypt(encrypted);
}
public static void DecryptWithoutHeader(Span<byte> bytes)
{
var encrypted = bytes[..Math.Min(bytes.Length, 0x1000)];
Decrypt(encrypted);
}
private static void Decrypt(Span<byte> bytes)
{
Logger.Verbose($"Attempting to decrypt block with NetEase encryption...");
var (encryptedOffset, encryptedSize) = ReadHeader(bytes);
var encrypted = bytes.Slice(encryptedOffset, encryptedSize);
var encryptedInts = MemoryMarshal.Cast<byte, int>(encrypted);
var encryptedInts = MemoryMarshal.Cast<byte, int>(bytes);
var seedInts = new int[] { encryptedInts[3], encryptedInts[1], encryptedInts[4], encrypted.Length, encryptedInts[2] };
var seedInts = new int[] { encryptedInts[3], encryptedInts[1], encryptedInts[4], bytes.Length, encryptedInts[2] };
var seedBytes = MemoryMarshal.AsBytes<int>(seedInts).ToArray();
var seed = (int)CRC.CalculateDigest(seedBytes, 0, (uint)seedBytes.Length);
var keyPart0 = seed ^ (encryptedInts[7] + 0x1981);
var keyPart1 = seed ^ (encrypted.Length + 0x2013);
var keyPart1 = seed ^ (bytes.Length + 0x2013);
var keyPart2 = seed ^ (encryptedInts[5] + 0x1985);
var keyPart3 = seed ^ (encryptedInts[6] + 0x2018);
for (int i = 0; i < 0x20; i++)
{
encrypted[i] ^= 0xA6;
bytes[i] ^= 0xA6;
}
var block = encrypted[0x20..];
var block = bytes[0x20..];
var keyVector = new int[] { keyPart2, keyPart0, keyPart1, keyPart3 };
var keysVector = new int[] { 0x571, keyPart3, 0x892, 0x750, keyPart2, keyPart0, 0x746, keyPart1, 0x568 };
if (block.Length >= 0x80)
@@ -65,7 +74,7 @@ namespace AssetStudio
var remainingCount = dataBlock.Length % 0x80;
if (remainingCount > 0)
{
var remaining = encrypted[^remainingCount..];
var remaining = bytes[^remainingCount..];
for (int i = 0; i < remainingCount; i++)
{
remaining[i] ^= (byte)(keyBlock[i] ^ ((uint)keysVector[(uint)keyVector[i % keyVector.Length] % keysVector.Length] % 0xFF) ^ i);