using System;
using System.Collections.ObjectModel;

namespace SUISS.Cloud.Crypto
{
	public class HmacSha256
	{
		public HmacSha256(byte[] key)
		{
			this._key = new byte[64];
			if (key.Length > 64)
			{
				ReadOnlyCollection<byte> readOnlyCollection = Sha256.HashBytes(new object[]
				{
					key
				});
				readOnlyCollection.CopyTo(this._key, 0);
			}
			else
			{
				Array.Copy(key, this._key, key.Length);
			}
		}

		public byte[] ComputeHash(byte[] message)
		{
			byte[] array = new byte[64];
			Array.Copy(this._key, array, 64);
			byte[] array2 = new byte[64];
			Array.Copy(this._key, array2, 64);
			for (int i = 0; i < 64; i++)
			{
				byte[] array3 = array;
				int num = i;
				array3[num] ^= 92;
				byte[] array4 = array2;
				int num2 = i;
				array4[num2] ^= 54;
			}
			ReadOnlyCollection<byte> readOnlyCollection = Sha256.HashBytes(new object[]
			{
				array,
				Sha256.HashBytes(new object[]
				{
					array2,
					message
				})
			});
			byte[] array5 = new byte[readOnlyCollection.Count];
			readOnlyCollection.CopyTo(array5, 0);
			return array5;
		}

		private const int BlockSize = 64;

		private byte[] _key;
	}
}