Possibility to apply a position information as part of a user’s authentication
David Jaroš, Radek Kuchta, Radimir Vrba[email protected]; [email protected]; [email protected] Faculty of Electrical Engineering and Communication
Brno University of Technology Brno, Czech Republic
Abstract
This paper describes basic possibilities of applying position information for the user authentication. There are described available methods for determining position with using Global Position System, Bluetooth and Wi-Fi wireless networks and also IQRF non standard communication network. A user authentication device developed for the secured authentication is described.
Keywords:
GPS, authentication, position, Bluetooth, Wi-Fi.1
Introduction
Authentication and authorization are asked almost everywhere in the today’s world. People must be identified when they download emails, read newspaper over the Internet, fill out forms for the government, access company private information, etc. For the user authentication some private credentials are usually required. In many cases users are using their unique identification number or username, and password. If one of these values is wrong, new enter is required. If more than selected number of attempts has been done, user’s account is locked. This described scenario is insufficient and some extra information is required for many situations and systems. The paper describes new possibility of using position data as one of the authentication information. When an information system has information about authenticated person’s position, it can change access rights or show only part of accessible data. There is more than one possibility how to get position. In all of them authenticated user has to have own identification device with position information. The authentication device can use different methods to determine current position. One of the possibilities is using GPS (Global Position System) or planed Galileo - European satellite navigation system. In this case, identification device is using satellite communication to obtain right position. The other chance is using company wireless network. In this case identification device is wirelessly connected to the selected wireless access point. There is possible to use Wi-Fi or Bluetooth wireless communication network. In all described contingencies the identification device could be a GSM cellular phone. So user doesn’t need any special device, it only needs software implementation and because cellular phone is connected to the GSM network, it is also other chance to find position.
2
Position determination
When position of a subject in the space is needed to know three basic conditions have to be fulfilled. First, the space where the subject is found should be described. The most often coordinates are used to describe of the space [3]. Secondly, enough of anchor points with known position have to be had. And finally, distance between the subject and anchor points have to be found. Number of used anchor points depends on dimension of the space [1]. Example for two dimensional system is depicted in Figure 1.
General equation used for position determination is
2 2
2
(
)
)
(
x
−
m
+
y
−
n
=
r
, (1)where m and n are coordinates of the centre of a circle (position of an anchor point), x and y are coordinates of points on the circle (possible position of the subject) and r is radius of the circle (distance between the anchor point and the subject). Then we can get equation system for getting position of our subject [4]
(2)
When equation system is solved, coordinates of position of the subject will be gotten (for our example 11,11).
11
;
11
6
)
11
(
)
17
(
65
,
5
)
7
(
)
7
(
83
,
5
)
14
(
)
6
(
2 2 2 2 2 2 2 2 2=
=
=
−
+
−
=
−
+
−
=
−
+
−
y
x
y
x
y
x
y
x
3
Global Position System
GPS (Global Position System) was developed by the United States Department of Defense. It is a satellite based navigation system. First GPS were used just for military objectives. Presently GPS is used in public sector and it is for free.
Whole main system consists of transmitters that orbit earth and receivers that process specially coded signal from transmitters (satellites). Around the earth orbit 24 satellites in standard case. Satellites orbit in six equally spaced orbital planes. For determination actual position of receiver, receiver needs to determine signal from at least four satellites (3 - dimensional space).
Distance between receiver and transmitter (satellite) is calculated using known delay of signal [8]. Transmitted signal contains coded time stamp, time when signal has been transmitted. When the signal is received, time delay is calculated. For this reason clocks in the transmitter and receiver must be very accuracy and synchronized. Transmitter contains atomic clock and accuracy time for receiver is calculated from several received signals. From known delay and known propagation speed of the signal distance between transmitter and receiver could be calculated. For calculating actual receiver position we need to know position of satellites. This information is transmitted with time stamp and is coded in signal, called ephemeris. Whole principle can be depicted in Figure 2.
Figure 2: Principle of GPS system.
3.1
Features of standard OEM GPS module
Nowadays GPS modules [6] offer up to 50 channels, they could receive signal from 50 satellites at the same time. They use various methods for fast fix, first fix can take under 1 second. Position update rate can be 4 Hz. Communication between GPS module and target application is provided by standard serial buses (UART, SPI, IIC, USB) and commonly by protocol NMEA 0183 [7].On the market is wide range of manufacturers of OEM GPS modules (u-blox, sirf, navsync…).
4
Bluetooth
Bluetooth is wireless technology that was designed for exchanging data or voice signal over short distances. Bluetooth use ISM (industrial, scientific, medical) unlicensed bandwidth 2,4 GHz. Range of Bluetooth is divided to 3 classes dependent on maximum permitted power. Maximal range is 100 m for class 1 with maximum permitted power 100 mW. Data rate for Bluetooth version 2.0 is up to 3 Mbps with EDR (Enhanced Data Rate) [9], [10].
Bluetooth can be used also for roughly localization of devices with this technology. In the area where we do localization must be a number of devices with known position (Access Points). Accuracy of determinate position is dependent on density of access points and their classes or maximum power. Accuracy is proportional to area where is localized device probably found. Situation can be described by Figure 3. In the first case the area of possible position is formed by circle area of range. For this reason it is better to use AP’s with smaller range (class 2, 3), but in the other hand it is increasing probability not to localize the device. In the second case localized device is in ranges of both access points, so it is able to reduce possible position to area that is common for each range.
Figure 3: Bluetooth localization.
Bluetooth method of localization can be useful for smaller area with high density of APs with short range, for example in factory area.
Variety of following cases can be derived from this simple method. [2] It is possible to combine this way of localization with the other wireless technologies like Wi-Fi, Zigbee or IQRF [5].
main objects are available. The first one is a user’s authentication device; the second one is an authentication server. There are two main steps also. In the first step user’s credentials are sent to the authentication authority. If user is known and fulfils all requirements, authentication authority will ask authentication device for the position information. If the user is in the selected range, he will be authenticated. It is a basic scenario that can be used for user’s authentication with position information. In the previous paragraph some basic possibility of using position information is described, in this part the easiest version of the authentication device is described. Block diagram of the first generation of the user authentication device connected to the user terminal is shown in Figure 5. User is using user terminal to connect to the authentication server in this scenario. This terminal is interconnected with the user authentication device via USB data bus. Described authentication device consist of central processor unit and secured data repository, where user’s credentials are stored. To start authentication process user has to unlock the device. In this case keyboard is used to enter input password. The authentication device is connected to the user terminal over the USB. There is a software tool that allows interconnection between the user authentication device and the authentication server on the client terminal.
If user is using standard computer without installed software or public computer, the authentication device also contains alphanumeric display where authentication instructions are shown. Thus, web access can be used for the user’s authentication.
Authentication device also contains finger print reader which can fill keyboard authentication or can increase security features.
User Authentication device Authentication server
Zpráva1
Hello
Hello, I'm server XYZ. Who are you? I'm user ABC.
Internal authentication process I don’t know you. Bye.
Authenticated user Create user
Hello user ABC. Where are you? Authentication failed
Position
Position check You’re out of allowed range. Bye.
Authentication failed
You’ve been authenticated.
Figure 5: The user’s authentication device connected over the user’s terminal to the authentication server.
6
Feature work
We are on the beginning of our work now. Some basic communication tests have been done and the first version of the authentication device has been developed. This device is using Global Position System to get information about the current position. In the next step we plan to create software tool for standard cellular phone with integrated GPS chip. The second generation of the authentication device will contain sophisticated software and wireless communication hardware. This configuration will allow connection to the company network over the Bluetooth and Wi-Fi access points. In this scenario authentication authority will connect to the authentication device over the wireless network with known topology.
7
Conclusions
The basic possibilities of user authentication enhanced with position information were described in this paper. The basic version of the user authentication device was also described. The device is using GPS for the position determination. Also other possibilities of wireless networks for position determination were described. The main aim of this paper was to give review of potentiality integration user position information to the authentication process with using user authentication device.
8
Acknowledgement
This research and the paper has been supported by the Czech Ministry of Education, Youth and Sports in the frame of MSM 0021630503 MIKROSYN New Trends in Microelectronic Systems and Nanotechnologies Research Project, and partly in 2C08002 Project - KAAPS Research of Universal and Complex
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