using System.IO;
using System.Security.Cryptography;

namespace ES3Internal
{
	public class AESEncryptionAlgorithm : EncryptionAlgorithm
	{
		private const int ivSize = 16;

		private const int keySize = 16;

		private const int pwIterations = 100;

		public override byte[] Encrypt(byte[] bytes, string password, int bufferSize)
		{
			using MemoryStream input = new MemoryStream(bytes);
			using MemoryStream memoryStream = new MemoryStream();
			Encrypt(input, memoryStream, password, bufferSize);
			return memoryStream.ToArray();
		}

		public override byte[] Decrypt(byte[] bytes, string password, int bufferSize)
		{
			using MemoryStream input = new MemoryStream(bytes);
			using MemoryStream memoryStream = new MemoryStream();
			Decrypt(input, memoryStream, password, bufferSize);
			return memoryStream.ToArray();
		}

		public override void Encrypt(Stream input, Stream output, string password, int bufferSize)
		{
			input.Position = 0L;
			using Aes aes = Aes.Create();
			aes.Mode = CipherMode.CBC;
			aes.Padding = PaddingMode.PKCS7;
			aes.GenerateIV();
			Rfc2898DeriveBytes rfc2898DeriveBytes = new Rfc2898DeriveBytes(password, aes.IV, 100);
			aes.Key = rfc2898DeriveBytes.GetBytes(16);
			output.Write(aes.IV, 0, 16);
			using ICryptoTransform transform = aes.CreateEncryptor();
			using CryptoStream output2 = new CryptoStream(output, transform, CryptoStreamMode.Write);
			EncryptionAlgorithm.CopyStream(input, output2, bufferSize);
		}

		public override void Decrypt(Stream input, Stream output, string password, int bufferSize)
		{
			using (Aes aes = Aes.Create())
			{
				byte[] array = new byte[16];
				input.Read(array, 0, 16);
				aes.IV = array;
				Rfc2898DeriveBytes rfc2898DeriveBytes = new Rfc2898DeriveBytes(password, aes.IV, 100);
				aes.Key = rfc2898DeriveBytes.GetBytes(16);
				using ICryptoTransform transform = aes.CreateDecryptor();
				using CryptoStream input2 = new CryptoStream(input, transform, CryptoStreamMode.Read);
				EncryptionAlgorithm.CopyStream(input2, output, bufferSize);
			}
			output.Position = 0L;
		}
	}
}