Dec2017-Script-Dump/ICSharpCode.SharpZipLib/Encryption/ZipAESTransform.cs

using System;
using System.Security.Cryptography;

namespace ICSharpCode.SharpZipLib.Encryption
{
	// Token: 0x02000026 RID: 38
	internal class ZipAESTransform : ICryptoTransform, IDisposable
	{
		// Token: 0x06000105 RID: 261 RVA: 0x00008134 File Offset: 0x00007134
		public ZipAESTransform(string key, byte[] saltBytes, int blockSize, bool writeMode)
		{
			if (blockSize != 16 && blockSize != 32)
			{
				throw new Exception("Invalid blocksize " + blockSize + ". Must be 16 or 32.");
			}
			if (saltBytes.Length != blockSize / 2)
			{
				throw new Exception(string.Concat(new object[]
				{
					"Invalid salt len. Must be ",
					blockSize / 2,
					" for blocksize ",
					blockSize
				}));
			}
			this._blockSize = blockSize;
			this._encryptBuffer = new byte[this._blockSize];
			this._encrPos = 16;
			Rfc2898DeriveBytes rfc2898DeriveBytes = new Rfc2898DeriveBytes(key, saltBytes, 1000);
			RijndaelManaged rijndaelManaged = new RijndaelManaged();
			rijndaelManaged.Mode = CipherMode.ECB;
			this._counterNonce = new byte[this._blockSize];
			byte[] bytes = rfc2898DeriveBytes.GetBytes(this._blockSize);
			byte[] bytes2 = rfc2898DeriveBytes.GetBytes(this._blockSize);
			this._encryptor = rijndaelManaged.CreateEncryptor(bytes, bytes2);
			this._pwdVerifier = rfc2898DeriveBytes.GetBytes(2);
			this._hmacsha1 = new HMACSHA1(bytes2);
			this._writeMode = writeMode;
		}

		// Token: 0x06000106 RID: 262 RVA: 0x00008248 File Offset: 0x00007248
		public int TransformBlock(byte[] inputBuffer, int inputOffset, int inputCount, byte[] outputBuffer, int outputOffset)
		{
			if (!this._writeMode)
			{
				this._hmacsha1.TransformBlock(inputBuffer, inputOffset, inputCount, inputBuffer, inputOffset);
			}
			for (int i = 0; i < inputCount; i++)
			{
				if (this._encrPos == 16)
				{
					int num = 0;
					for (;;)
					{
						byte[] counterNonce = this._counterNonce;
						int num2 = num;
						if ((counterNonce[num2] += 1) != 0)
						{
							break;
						}
						num++;
					}
					this._encryptor.TransformBlock(this._counterNonce, 0, this._blockSize, this._encryptBuffer, 0);
					this._encrPos = 0;
				}
				outputBuffer[i + outputOffset] = inputBuffer[i + inputOffset] ^ this._encryptBuffer[this._encrPos++];
			}
			if (this._writeMode)
			{
				this._hmacsha1.TransformBlock(outputBuffer, outputOffset, inputCount, outputBuffer, outputOffset);
			}
			return inputCount;
		}

		// Token: 0x1700002F RID: 47
		// (get) Token: 0x06000107 RID: 263 RVA: 0x0000831C File Offset: 0x0000731C
		public byte[] PwdVerifier
		{
			get
			{
				return this._pwdVerifier;
			}
		}

		// Token: 0x06000108 RID: 264 RVA: 0x00008324 File Offset: 0x00007324
		public byte[] GetAuthCode()
		{
			if (!this._finalised)
			{
				byte[] array = new byte[0];
				this._hmacsha1.TransformFinalBlock(array, 0, 0);
				this._finalised = true;
			}
			return this._hmacsha1.Hash;
		}

		// Token: 0x06000109 RID: 265 RVA: 0x00008361 File Offset: 0x00007361
		public byte[] TransformFinalBlock(byte[] inputBuffer, int inputOffset, int inputCount)
		{
			throw new NotImplementedException("ZipAESTransform.TransformFinalBlock");
		}

		// Token: 0x17000030 RID: 48
		// (get) Token: 0x0600010A RID: 266 RVA: 0x0000836D File Offset: 0x0000736D
		public int InputBlockSize
		{
			get
			{
				return this._blockSize;
			}
		}

		// Token: 0x17000031 RID: 49
		// (get) Token: 0x0600010B RID: 267 RVA: 0x00008375 File Offset: 0x00007375
		public int OutputBlockSize
		{
			get
			{
				return this._blockSize;
			}
		}

		// Token: 0x17000032 RID: 50
		// (get) Token: 0x0600010C RID: 268 RVA: 0x0000837D File Offset: 0x0000737D
		public bool CanTransformMultipleBlocks
		{
			get
			{
				return true;
			}
		}

		// Token: 0x17000033 RID: 51
		// (get) Token: 0x0600010D RID: 269 RVA: 0x00008380 File Offset: 0x00007380
		public bool CanReuseTransform
		{
			get
			{
				return true;
			}
		}

		// Token: 0x0600010E RID: 270 RVA: 0x00008383 File Offset: 0x00007383
		public void Dispose()
		{
			this._encryptor.Dispose();
		}

		// Token: 0x04000093 RID: 147
		private const int PWD_VER_LENGTH = 2;

		// Token: 0x04000094 RID: 148
		private const int KEY_ROUNDS = 1000;

		// Token: 0x04000095 RID: 149
		private const int ENCRYPT_BLOCK = 16;

		// Token: 0x04000096 RID: 150
		private int _blockSize;

		// Token: 0x04000097 RID: 151
		private ICryptoTransform _encryptor;

		// Token: 0x04000098 RID: 152
		private readonly byte[] _counterNonce;

		// Token: 0x04000099 RID: 153
		private byte[] _encryptBuffer;

		// Token: 0x0400009A RID: 154
		private int _encrPos;

		// Token: 0x0400009B RID: 155
		private byte[] _pwdVerifier;

		// Token: 0x0400009C RID: 156
		private HMACSHA1 _hmacsha1;

		// Token: 0x0400009D RID: 157
		private bool _finalised;

		// Token: 0x0400009E RID: 158
		private bool _writeMode;
	}
}