sheikh iqbal ahamed marquette university, milwaukee, wisconsin, usa [email protected] 1 secured tag...

Sheikh Iqbal Ahamed

Marquette University, Milwaukee,

Wisconsin, USA

[email protected]

1

Secured Tag Identification Using EDSA

(Enhanced Distributed Scalable Architecture)

Farzana RahmanBangladesh Univ. of Eng. & Tech.

Dhaka, [email protected]

Md. Endadul HoqueBangladesh Univ. of Eng. & Tech.

Dhaka, [email protected]

Outline

2

Basic introduction to RFID technology.

What is meant by privacy protection and scalability.

Problems of unsecure and non-scalable RFID application.

Importance of secure and scalable RFID application.

Overview of related work.

Our contribution

Hexagonal Cell Based Architecture – alleviates scalability problem.

Use of serverless protocols for authentication and search purposeReduces setup and maintenance cost. In case of emergency situation, usage of serverless protocol is

practical and feasible.Now back-end server can be devoted to some higher level

maintenance.

Evaluation - use of our architecture in emergency evacuation system.

Conclusion & Future work

Introduction – Radio Frequency Identification Technology

3

Radio Frequency Identification (RFID) is a type of automatic

identification system.

Each tag has a unique ID. An authorized reader can identify a tag by

communicating through radio transmission.

Mass exploitation of RFID technology requires the entire system to be

scalable.

But if used improperly, RFID application has the potential to jeopardize

consumer privacy.

Our main concern :

Privacy protection – how can we ensure that users privacy is not

hampered?

Ensuring scalability – how can we ensure scalability when the

number of tags increase continually?

Important terms and their definitions

4

What is Security in the context of RFID applications?RFID technology may bring spontaneous risks because of the

proliferation of RFID tags. So RFID applications must be secure against all

major attacks that are possible to be done by the adversaries.

What is Privacy Protection? By privacy protection we mean that a tag cannot be tracked by an

adversary without tampering it and realizing all its stored information.

What is Scalability? Scalability means that a reader can find a tag’s ID with constant

computational time regardless of the number of tags that is owned by it.

Problems of Unsecured and Non-scalable RFID application

5

Security problemsWhile applying RFID tags to individual objects, there exists a

possibility that these items can be tracked. Individuals having these items can be followed to know what

items they carry.Surely nobody wants to be traced. So to capture future market

RFID applications need to be secured and protected.

Scalability problemsPrivate tag identification involves decryption the of ID of the

tag which is identified by exhaustive search.Definitely this will not ensure scalability when the number of

tag increases.But many real life RFID application needs to maintain

scalability throughout the lifetime of their application, no matter how large the number of tags is.

Importance of Secure and Scalable RFID application

6

So, we now know that Privacy Protection & Scalability are two conflicting goals !!

But Some real life application of RFID requires the

entire system to be protected against all type of

security attacks.

These systems also need to be scalable over the

entire lifetime of the system.

Importance of Secure and Scalable RFID application (Cont.)

7

So we realized that both strong privacy protection and

scalability are very important for the real life

implementation of RFID technology.

No matter how many tags are present, the system should

be scalable and secure against all attacks.Adversary: WOW! So

many tags, but how can we

reach them now??

System is secure and adversary

cannot attack no matter how many tags are in the system

Yes, We are safe now

Secure

Shield

8

A. Solanas et al. first contributed to mitigate scalability

problems with a distributed architecture for RFID privacy-

preserving technique.

According to them, an area is divided into cells where each

cell was assumed as square shape.

Here tags capable of performing simple cryptographic

computation can use improved randomized hash lock in a

scalable manner to send its encrypted ID to the reader.

Other authentication techniques can be used in addition to

improved randomized hash lock.

Related work

9

Scalability is ensured by using information sharing

protocol suites, though the system would be more

scalable by assuming different structure of a cell.

There is no explicit mention of a search option.

Related work (Cont.)

10

We propose a distributed architecture for large scale

application where not only secure RFID authentication is

needed, but also efficiency, cost-effectiveness and

accuracy are a great concern.

Then we address some challenges in emergency

evacuation system and demonstrate how our system

resolves those.

Our system is actually an improved version of the

architecture that was proposed by A. Solanas et al. We try

to alleviate the shortcomings noticed in that architecture.

Overview of our approach

11

Our system comprises its components, their location and

capabilities, and their privacy and search functionalities.

ComponentsRFID reader, tags and back-end server are defined as main

components of the system.

The tags are assumed to be passive. We also assume tag

can compute simple one way hash functions and generate

random numbers. Moreover, tags can change their

location at any time.

On the other hand, readers are static and active devices.

They are capable of detecting tags by performing crucial

functions. To cover an area, readers are logically

distributed.

Details of our approach

12

The proposal of Solanas et al. had square cells. In our

architecture the area is divided into equal hexagon and each is

covered by a single reader.

We refer to each hexagon as a cell which improves our system.

Each single reader covers a specific cell. Our assumption

includes that all communication channel are secure.

The backbone of our system is a back-end server. It can access

database of tag IDs. On basis of requirements, server can

communicate with each reader.

In spite of having a back-end server in the system, ours does not

comply with a centralized scheme. In fact, it is a servered as well

as serverless scheme.

Details of our approach (Cont.)

13

Coverage AreaThe readers are spatially distributed and tags are

scattered among them. Consider an area S which can be covered by a couple of readers. We have two permitted points called ENtrance Point (ENP) and EXit Point (EXP) for tags to enter or exit the area S respectively. The size of each cell, covered by each reader, is equal. denotes the cell of S . Formally, we consider

Suppose, cell is covered by reader . Also, is the set of readers adjacent to .


thi

iC

iC

iR

iR

14

Privacy and SearchServerless authentication and search protocol is used in

our system for authentication and search of tags.

Protocols and Functionalities

There will be three types of communication in our system.

1)

Between tag and reader, there will be two types of

functionalities. One is for authentication and other

is for search. Here each reader can perform like a

serverless reader. However a reader can

communicate with the back-end server.


15

2)

A reader can share its information with its adjacent

readers. The shared information (Ownership

Information) contains the used for a tag along

with the tag ID and reader ID of the reader which locates

the particular tag within its cell.

If a reader locates a tag in , then after

authentication, reader will send its (Ownership

Information ) to all its adjacent readers. All the adjacent

readers store this Ownership Information in their contact

lists so that they can authenticate this tag whenever it

enters one of their cells.


iCjTiR

jT

16

In order to communicate between the readers three protocols are

proposed.

Arrival ProtocolThis protocol starts when a tag enters the system through ENP.

At the very beginning all readers other than that at ENP own no tags.

Whenever an authorized tag enters the system through ENP, after

authentication

sends the ownership information to all its adjacent readers.

Otherwise alerts the system about the attempt of an unauthorized

tag.

When an authorized tag enters into a cell, reader of that cell

authenticates the tag without any involvement of the back-end server.

Because the contact list of the reader is supposed to have tag’s

ownership information. And this information was received from any of its

adjacent readers where the tag lived before.


ENPRENPR

17

Roaming ProtocolThis protocol sets off when a tag enters a cell equipped

with a reader from another cell.

If a tag enters a cell of a reader ( ) which is adjacent

to the cell in which it was residing before ( ), the tag

will be authenticated as already has the ownership

information of the tag.

After authentication will send the ownership

information to all of its adjacent readers.

Now depending on the information in its contact lists,

each adjacent reader takes measurements differently.


iR

ownR

iR

iR

18

Departure ProtocolWhenever a tag is about to exit the system through EXP, this

protocol starts.

When tag reaches the EXP to exit from the system,

sends the ownership information to its adjacent readers to

erase the information of the tag as there is no chance to go

back.

Moreover, the previous owner (reader) propagates this

information to its neighboring readers to remove the tag’s

ownership information from their contact lists.

Hence nothing remains in the system about the departed

tag.


jT EXPR

19

3)

Our system is equipped with a back-end server which can

efficiently access a database of tag IDs. Server can authorize all

readers. But it authorizes only for tags. Server monitors

the system constantly.

The server can do a search whenever it faces a request from

application.

Server just sends a search request to all the readers in the

system along with tag ID for which readers have to perform

a search. However, only those readers that have ownership

information related to this tag invokes the search operation,

while other readers remain silent. Whenever a reader locates

the tag within its cell, it replies to server with the search result.


20

Through searching for a tag, server ascertains in which cell

the tag actually is. This feature can be used in the application

where locating or tracking of something is required.

For this back-end server, we cannot refer our system as

entirely serverless. Though intervention of the server is

limited to search, authorization, monitoring, etc., we cannot

deny the presence of back-end server.

Justification of Enhanced Cell Organization

Our system is improved by introducing hexagonal cell. There are

several reasons behind it.

Depending on the mobility purpose, a tag can be at

different locations at different times.


21

For locating a tag, a reader faces

five different situations in case of

square cell (see Fig.2) and four

different situations in case of

hexagonal cell (see Fig.1).

Using square area as a cell a tag

can be located by at most four

readers at a time. However using

hexagonal cell a tag can be located

by at most three readers at a time.

As a result, it reduces the traffic of

communication channel between

reader and server.


Fig.1

Fig.2

22

In hexagonal cell organization, total number of adjacent

readers of a specific reader is less than that in square cell

organization.

In our system, whenever a tag changes its location from one

cell to another, at most 3 readers have to add the ownership

information of the particular tag into their contact lists and at

most 3 readers have to delete the information. While in

previous system, at most 5 readers do insertion and at most 5

readers do deletion. Thus, our system ensures more scalability.

Radio frequency is omni-directional. So a cell should be

circular. But practically circular cell is not possible. A hexagon

has more resemblance to a circle than a square.


23

In square pattern, all the neighboring readers of a reader are

not at an equal distance. Some neighbors are at distance

while others are at √2 distance. In contrast, all neighboring

readers in hexagonal pattern are at an equal distance .


A hexagonal pattern

provides a reduced

overlapping area. The area

is reduced by

for a single cell (see Fig.3).Fig.3

24

Emergency evacuation system is a real life situation in

which RFID tags can be used -

to keep track of each and every person stuck in danger

persons who were unable to leave the danger premises and

persons who were undetected.

It will raise scalability problem with typical RFID systems.

Our proposed enhanced distributed architecture can be

used in this situation as it ensures scalability and security

by using serverless RFID authentication and search

protocols.

Evaluation

25

The emergency evacuation system must be able to keep track

of who is entering and leaving the system on a hands-free

basis.

It must cover all entrances/exits and handles people one-by-one

basis. But in case of any emergency it needs to handle a

number of people at a time, because there is no time for a

personnel to think in which pocket a personnel card was kept

and to use it to exit the building.

Even it has to know more specifically who has already entered

the system so that it can determine who are still inside at the

time of emergency.

Because of these situations, EDSA accompanied by RFID can be

the appropriate solution to the architecture of the system.

Evaluation (Cont.)

26

For more than one entrance or exit point more than one ENP

or EXP have to be build in EDSA.

To account for personnel, building occupants must have ID

card, badge or other cards with embedded RFID tag.

As a tag needs to be authenticated to enter the system, the

ENPs of EDSA can be authorized by back-end server for all

possible tags that can enter through them.

ENPs are placed in every possible entry point in the system.

So that each people entering the building through any gate

must be accounted.

Whenever it is required, the back-end server can keep track

the whereabouts of people by executing a search operation.

Evaluation (Cont.)

27

Those who have entered and

who are still inside can readily

be available to back-end server

by getting information from the

contact lists of readers.

The back-end server can come

to know about the sparse

distribution of people

throughout the whole building.

The back-end server can

provide total numbers of

people left in the building as

well as who are leaving the

building through EXPs.

Evaluation (Cont.)

EXIT

Fire !

Fire !

Ms. Linda has left the building. Oh no!! Rachel

is still inside. We

have to save her.

28

The automated system concept must be based on a “hands-

off” approach and require no user intervention upon entry or

exit. In fact, EDSA follows the hands-off approach.

As buildings grow and workplace increase in size in recent

times, the need for more sophisticated emergency systems

grows.

Accurate location information is essential to any emergency

system and thus the implementation of RFID and EDSA is

crucial to the society.

Evaluation (Cont.)

29

Implementation of EDSA in real life scenario.

Simulation results can be used to evaluate the success

rate in real circumstances.

Future Work

30

RFID systems will be widely used in the future

depending on the strength of privacy protection and

the improvement of performance features such as

scalability.

Unfortunately, there is a trade-off between

maintaining scalability and ensuring security.

Our architecture incorporates these two conflicting

goals. Logically it can be successfully implemented in

real-life situation like Emergency Evacuation System.

Conclusion

sheikh iqbal ahamed marquette university, milwaukee, wisconsin, usa [email protected] 1 secured tag...

Documents