v0.80.30

2023-01-06 22:33:59 +04:00
parent a3cf868dfb
commit 2b31232b30
178 changed files with 5213 additions and 23780 deletions
--- a/AssetStudio/Crypto/BlkUtils.cs
+++ b/AssetStudio/Crypto/BlkUtils.cs
@@ -0,0 +1,59 @@
+using System;
+using System.Buffers.Binary;
+
+namespace AssetStudio
+{
+    public static class BlkUtils
+    {
+        private const int KeySize = 0x1000;
+        private const int SeedBlockSize = 0x800;
+
+        public static CryptoStream Decrypt(FileReader reader, Blk blk)
+        {
+            reader.Endian = EndianType.LittleEndian;
+
+            var signature = reader.ReadStringToNull();
+            var count = reader.ReadInt32();
+            var key = reader.ReadBytes(count);
+            reader.Position += count;
+            var seedSize = Math.Min(reader.ReadInt16(), blk.SBox.IsNullOrEmpty() ? SeedBlockSize : SeedBlockSize * 2);
+
+            if (!blk.SBox.IsNullOrEmpty() && blk.Type.IsGI())
+            {
+                for (int i = 0; i < 0x10; i++)
+                {
+                    key[i] = blk.SBox[(i % 4 * 0x100) | key[i]];
+                }
+            }
+
+            AES.Decrypt(key, blk.ExpansionKey);
+
+            for (int i = 0; i < 0x10; i++)
+            {
+                key[i] ^= blk.InitVector[i];
+            }
+
+            ulong keySeed = ulong.MaxValue;
+
+            var dataPos = reader.Position;
+            for (int i = 0; i < seedSize; i += 8)
+            {
+                keySeed ^= reader.ReadUInt64();
+            }
+            reader.Position = dataPos;
+
+            var keyLow = BinaryPrimitives.ReadUInt64LittleEndian(key.AsSpan(0, 8));
+            var keyHigh = BinaryPrimitives.ReadUInt64LittleEndian(key.AsSpan(8, 8));
+            var seed = keyLow ^ keyHigh ^ keySeed ^ blk.InitSeed;
+
+            MT19937_64.Init(seed);
+            var xorpad = new byte[KeySize];
+            for (int i = 0; i < KeySize; i += 8)
+            {
+                BinaryPrimitives.WriteUInt64LittleEndian(xorpad.AsSpan(i, 8), MT19937_64.Int64());
+            }
+
+            return new CryptoStream(reader.BaseStream, xorpad);
+        }
+    }
+}