System.Web.Security.RolePrincipal.DecryptTicket C# (CSharp) Method

		void DecryptTicket (string encryptedTicket)
		{
			if (encryptedTicket == null || encryptedTicket == String.Empty)
				throw new ArgumentException ("Invalid encrypted ticket", "encryptedTicket");

			byte [] ticketBytes = GetBytesFromBase64 (encryptedTicket);
			byte [] decryptedTicketBytes = null;

			CookieProtection cookieProtection = RoleManagerConfig.CookieProtection;

			if (cookieProtection == CookieProtection.All) {
				decryptedTicketBytes = MachineKeySectionUtils.VerifyDecrypt (MachineConfig, ticketBytes);
			} else if (cookieProtection == CookieProtection.Encryption) {
				decryptedTicketBytes = MachineKeySectionUtils.Decrypt (MachineConfig, ticketBytes);
			} else if (cookieProtection == CookieProtection.Validation) {
				decryptedTicketBytes = MachineKeySectionUtils.Verify (MachineConfig, ticketBytes);
			}

			if (decryptedTicketBytes == null)
				throw new HttpException ("ticket validation failed");

			MemoryStream ticket = new MemoryStream (decryptedTicketBytes);
			BinaryReader reader = new BinaryReader (ticket);

			// version
			_version = reader.ReadInt32 ();

			// issued date
			_issueDate = new DateTime (reader.ReadInt64 ());

			// expire date
			_expireDate = new DateTime (reader.ReadInt64 ());

			// cookie path
			_cookiePath = reader.ReadString ();
			
			// roles
			string roles = reader.ReadString ();

			if (!Expired) {
				InitializeRoles (roles);
				//update ticket if less than half of CookieTimeout remaining.
				if (Roles.CookieSlidingExpiration){
					if (_expireDate-DateTime.Now < TimeSpan.FromTicks (RoleManagerConfig.CookieTimeout.Ticks/2))	{
						_issueDate = DateTime.Now;
						_expireDate = DateTime.Now.Add (RoleManagerConfig.CookieTimeout);
						SetDirty ();
					}
				}
			} else {
				// issue a new ticket
				_issueDate = DateTime.Now;
				_expireDate = _issueDate.Add (RoleManagerConfig.CookieTimeout);
			}
		}