A Survey Of RFID Authentication Protocols Based On Hash-Chain Method

A Survey of RFID Authentication Protocols Based on
Hash-Chain Method
Irfan Syamsuddina
, Tharam Dillonb
, Elizabeth Changc
, and Song Hand
a
State Polytechnic of Ujung Pandang, Indonesia
b,c,d
DEBI Institute, Curtin University of Technology, Australia
irfans@ poliupg.ac.id, tharam@it.uts.edu.au, change@cbs.curtin.edu.au,
song.han@cbs.curtin.edu.au
Abstract
Security and privacy are the inherent problems in
RFID communications. There are several protocols
have been proposed to overcome those problems. Hash
chain is commonly employed by the protocols to
improve security and privacy for RFID authentication.
Although the protocols able to provide specific
solution for RFID security and privacy problems, they
fail to provide integrated solution. This article is a
survey to closely observe those protocols in terms of its
focus and limitations.
Keywords: RFID, security, privacy, hash chain.
1. Introduction
Radio frequency identification or RFID was first
used during the Second World War in Identification
Friend or Foe systems onboard military aircraft. Soon
after, Harry Stockman demonstrated a system
energized completely by reflected power. Then in
1960s, the first Electronic Article Surveillance anti-
theft systems were commercialized. Later, in 1970s,
the US Department of Energy investigated the
technology’s potential to safeguard materials at nuclear
weapons sites [17].
Recently, radio frequency identification (RFID) has
been regarded as the main driver of the future
ubiquitous technology. It is also claimed as the core
technology to realize internet of things environment
where large amount of items are connected seamlessly
anytime and anywhere [2]. RFID offers simplicity for
people to object (P2O) and object to object (O2O)
communications. It is believed that it will play a
significant role for future ubiquitous society [11].
Generally, RFID systems consist of Radio
Frequency Identification (RFID) tags and RFID
readers. While RF tags operate as transponders, RF
readers act as transceivers. In case of a more complex
application, a database server is required to store
information comes from both transponders and
receivers sides [12].
It is assumed that communication between RF tags
and server is secure. The process of RFID
communication can be described as follows, RFID
reader request access to the RFID tag and return the
reply to the database server. After identification and
authentication on server side, then server will return
the information of RFID tag to the reader [12][13].
Automatic identification is the basic characteristic of
RFID. In its simplest form, identification can be
binary, e.g., paid or nor paid which is useful for
alerting. Therefore, alerting is become the next
powerful feature of RFID. Also, RFID enable real time
monitoring to a large number of in a short time. In
addition, RFID has ability to perform on-chip
computation, accordingly it support cryptographic
protocol for authentication. In general, RFID has four
basic capabilities, identification, alerting, monitoring,
and authentication [9].
RFID has become a new and exciting area of
technological development, and is receiving increasing
amounts of attention. There is tremendous potential for
applying it even more widely, and increasing numbers
of companies have already started up pilot schemes or
successfully used it in real-world environments.
Based on the various industry areas that are featured
in the reviewed literature, RFID technology is widely
used in many areas such as
- Animal detection.
- Aviation.
- Transportation.
- Building management.
- Construction.
Third 2008 International Conference on Convergence and Hybrid Information Technology
978-0-7695-3407-7/08 $25.00 © 2008 IEEE
DOI 10.1109/ICCIT.2008.314
559
Third 2008 International Conference on Convergence and Hybrid Information Technology
978-0-7695-3407-7/08 $25.00 © 2008 IEEE
DOI 10.1109/ICCIT.2008.314
559
Authorized licensed use limited to: Seoul National University. Downloaded on August 14,2010 at 15:00:52 UTC from IEEE Xplore. Restrictions apply.

- Enterprise feedback control.
- Fabric and clothing.
- Food safety warranties.
- Health,
- Military, etc.
Therefore, RFID related business experiences many
significant advantages. Das [21] confirms market
research report from IDTechEx that the increasing
sales of RFID tags for the 60 years up to the beginning
of 2006 reached 2.4 billion, which was accounted for
more than 600 million tags being sold in 2005. Then in
2006, it was expected that approximately 1.3 billion
tags and 500 million RFID smart labels would be
needed in a range of areas, such as retailing, logistics,
animals and farming, library services, and military
equipment.
In terms of academic point of view, RFID is
regarded as an exciting research area due to its relative
uniqueness and exploding growth. RFID research has
led to the emergence of a new academic research area
that builds on existing research in a host of disciplines,
such as electronic engineering, information systems,
computer science, environmental science, medical and
public health and also business strategic management,
and there has been a significant increase in the number
of papers on RFID in research journals [20]. As noted
by Heinrich [22], RFID is likely to be among the most
exciting and fastest-growing technologies in terms of
scope of application in the next generation of business
intelligence which attract many researchers from
different field to collaborate in a specific research.
However, to continue the advancement of
knowledge in this area, it is important to understand
the current status of RFID research and to examine
contemporary trends in the research domain. It is vital
to determine the principal concerns of current RFID
research, whether technological, application related, or
security related. An academic review of the literature is
essential for appropriately shaping future research.
One of a growing area in RFID literature is
authentication protocol with hash chain model which
will be deeply discussed in this paper. The rest of this
paper is organized as follows. In the next section, we
will briefly review security and privacy issues of
RFID. The application of hash chain in RFID
authentication is presented in Sections 3. In Section 4,
we propose our comparative study of recent RFID
authentication protocols based on hash chain model.
And some conclusions will be made in the last section.
2. Security and privacy of RFID
RFID technology poses exclusive privacy and
security concerns since it is promiscuous the tags
themselves typically maintain no history of past
readings. As a result, security and privacy issues are
considered as the fundamental issue the RFID
technology [4][12].
2.1. Security Objectives
Although generally it is assumed that
communication between RFID tag and the readers is
secure, yet since it is basically wireless based
communication, a number of security and privacy
issues could not be avoided. Fundamental information
security objectives, such as confidentiality, integrity,
availability, authentication, authorization, non-
repudiation and anonymity are often not achieved
unless special security mechanisms are integrated into
the system [23].
The privacy aspect has gained special attention for
RFID systems. Consumers may carry objects with
silently communicating transponders without even
realising the existence of the tags. Passive tags usually
send their identifier without further security
verification when they are powered by electromagnetic
waves from a reader. The ID information can also be
linked to other identity data and to location
information. Consumers might employ a personal
reader to identify tags in their environment but the
large number of different standards may render this
difficult. Therefore, user privacy is the main
consideration of RFID security.
2.2. Security Properties
A. Confidentiality
The communication between reader and tag is
unprotected in most cases. Eavesdroppers may thus
listen in if they are in immediate vicinity. Furthermore,
the tag’s memory can be read if access control is not
implemented.
B. Integrity
With the exception of high-end ISO 14443 systems
which use message authentication codes (MACs), the
integrity of transmitted information cannot be assured.
Checksums (CRCs) are often employed on the
communication interface but protect only against
random failures. Furthermore, the writable tag memory
can be manipulated if access control is not
implemented.
560
560

C. Availability
Any RFID system can easily be disturbed by
frequency jamming. But, denial-of-service attacks are
also feasible on higher communication layers.
D. Authenticity
The authenticity of a tag is at risk since the unique
identifier (UID) of a tag can be spoofed or
manipulated. The tags are in general not tamper
resistant.
2.3. RFID Security and Privacy Schema
To get a clear understanding on how those security
and privacy issues exist within RFID technology, a
schema introduced in [17] is presented.
Garkenfield, et.al. [17] clearly describe the actual
existing security and privacy problems within RFID
technology as can be seen in figure 1.
Figure 1. Security and Privacy threats within RFID
They use the Electronic Product Code (EPC) based
schema as a popular account of RFID technology. It
shows where security and privacy threats exist within
common RFID applications.
Physical attacks, denial of service, man in the
middle attack, eavesdropping, traffic analysis,
counterfeiting, and tag cloning attack are several
security related problems commonly addressed to
RFID technology [10][17].
In terms of privacy, RFID is mainly questioned in
tracking and inventorying capabilities. Another privacy
concern is authentication problem. Authenticating legal
communication between RFID tag and reader is the
main question intensive studies in this field
[10][12][13].
This paper surveys some papers that introduce RFID
authentications with hash chain method.
3. Hash Chain Model and Its applications
in RFID authentication
Hash chain is basically a cryptography approach for
safeguarding against password eavesdropping which is
firstly proposed in [7]. Now, it can be found in other
applications such as micropayment systems and RFID
authentication due to elegant and versatile low-cost
associated to this technique.
Lamport [7] describes that a hash chain of length N
could be constructed by applying a one-way hash
function h(.) recursively to an initial seed value s.
hN
(s) = h(h(...h(s)...)) (N times)
The last element hN(s) is also called the tip T of the
hash chain. By knowing hN
(s), hN-1
(s) can not be
generated by those who do not know the value s,
however given hN-1
(s), its correctness can be verified
using hN
(s). This property of hash chains has evolved
from the property of one-way hash functions [7].
Then, the application of hash chain model into RFID
application is firstly introduced by Ohkubo et.al [8].
After reviewing previous protocols for improving
privacy of RFID applications, they suggest five points
for an approach to RFID scheme design.
- keep complete user privacy.
- eliminate the need for extraneous rewrites of the
tag information.
- minimize the tag cost.
- eliminate the need for high power of computing
units.
- provide forward security.
Their protocol for secure RFID privacy protection
scheme is described as follows [8].
.
Figure 2. Hash chain in RFID application.
Hash chain technique is employed to renew the
secret information contained in the tag from G to H.
The following is a brief description how it works. In
561
561

the beginning, a tag has initial information s1. In the i-
th transaction with the reader, the RFID tag will do two
things:
1. Sends answer ai = G(si) to the reader,
2. Renews secret si+1 = H(si) as determined from
previous secret si,
where H and G are hash functions, as in Figure 1.
The reader sends ai to the back-end database.
The back-end database maintains a list of pairs (ID,
si), where si is the initial secret information and is
different for each tag. So the back-end database that
received tag output ai from the reader calculates a0i =
G(Hi(si)) for each si in the list, and checks if ai a’i.
Then, it will find a’i, a’i = ai, then return the ID, which
is a pair of a’i.
This is the basic hash chain method implementing
in RFID authentication protocol which is then followed
by many researchers by proposing new protocols in
different perspectives and techniques.
4. Comparative study of hash chain based
RFID authentication protocols
This part will discuss several RFID authentication
protocols that using hash chain as a method for
properly enhancing security and privacy of RFID. We
introduce hash chain method of each protocol and
review its limitation. There are ten protocols of RFID
authentication with hash chain will be compared in this
section.
As mentioned earlier, Ohkubo et al. [8] proposed a
hash-based authentication protocol. The aim of the
protocol is to provide better protection of user privacy
with the basic concept of refreshing the identifier of the
tag each time it is queried by a reader. The protocol
changes RFID identities on each read based on hash
chains. Hash chain method is used in this two ways
communication of RFID tag. This protocol does not
require a random number generator. However, it is
confirmed that this protocol is flawed to certain replay
attacks.
The next protocol is a cryptographically controlled
access protocol for RFID tag by using hash locks was
proposed by Weis et al. [15]. They argue that although
the hash value can be read out by any reader, yet only
authorized ones would be able to look up the tags key
in a database of key-hash pairs. The objective of this
protocol is improving RFID tag security and privacy
by using an integrated hash function where key could
be verified by comparing the key hash with the stored
hash value. The drawback of this protocol is that the
static hash value would still be traceable.
In addition, Molnar et al. [4] proposed a hash-tree
based authentication protocol for RFID tags. They
exposed privacy issues related to RFID in libraries,
described current deployments, and suggested novel
architectures for library RFID. This protocol utilizes a
dynamic amount of computation required per tag,
which depends on the number of tags available in the
hash-tree. However, the protocol is confirmed has a
serious problem, where another security leak will arise
if the tag lost. In this case, anonymity for the rest of the
hash-tree group may be compromised by attacker.
Therefore, the protocol does not provide for forward-
anonymity.
The following approach is the hash chain based
RFID authentication protocol by Henrici [3]. This
protocol only requires a hash function in the tag and
data management at the back-end. It offers a high
degree of location privacy and is resistant to many
forms of attacks. Further, only a single message
exchange is required, the communications channel
needs not be reliable and the reader/third party need
not be trusted, and no long-term secrets need to be
stored in tags. However, the limitation of this protocol
is that it does not guarantee to provide full privacy,
since the tag is vulnerable to tracing when the attacker
interrupts the authentication protocol mid-way.
Therefore, this approach also has
Then, Avoine [5] introduced the modification of
authentication protocol. This proposed protocol is
aimed at solving the replay attack problem of [8]. He
argued that privacy issues cannot be solved without
looking at each layer separately, where RFID system
has three layers, application, communication and
physical. Yet, it does not consider the issue of
availability, and the protocol is vulnerable to attacks
where the attacker forces an honest tag to fall out of
synchronization with the server so that it can no longer
authenticate itself successfully.
Similarly, anonymous RFID protocol is also offered
by Dimitriou [19]. The objective of this protocol is to
protecting forward privacy from cloning and privacy
attacks. Mutual authentication is performed within the
protocol based on the use of secrets which are shared
between tag and database, and refreshed to avoid tag
tracing. Yet, limitation of the protocol is addressed to
desynchronization problem which occurs in database
side. This is confirmed to be vulnerable from man in
the middle attack.
The following protocol is offered by Rhee et al. [6].
It is called hash-based challenge-response which is
aimed at providing security protection mechanism
from the replay and spoofing attacks. The proposed
562
562

protocol is based on challenge response using one-way
hash function and random number which is claimed
suitable for security database environment. Hash chain
function is used in the protocol to guarantee secret key
in the form of ID. Then, the tag does not need to
update the secret key which avoids attacks by
interrupting the session. However, this solution does
not provide forward secrecy which means if a tag can
be compromised then attacker will be able to trace the
past communications from the same tag.
Lee et al. [18] proposed a new RFID authentication
protocol with hash chain. The objective of this effort is
to solve the desynchronization problem by maintaining
a previous identification number in the database server.
However, since the hashed identification number is
always identical, an adversary who queries tag actively
without updating identity able to trace the RFID tag.
Unfortunately, although it able to secure
desynchronization problem, this protocol still suffer
from traceability attack which is become a serious
limitation of the protocol to solve privacy problem of
RFID.
Likewise, RFID authentication scheme whith a hash
function and synchronized secret information was
introduced by Lee, et.al. [14]. The protocol is aimed at
securing user privacy including against tag cloning
attack through an additional hash operation.
Unfortunately, this protocol suffers from
desynchronization attacks that could be conducted by
adversaries. This occurs due to unavailability of PRNG
in the RFID tag while the server does not know how
many times an RFID tag may have not yet updated its
secret information.
Finally, Han,et.al. [13] offer new kind of mutual
authentication protocol to solve some problems of
previous protocols. In their protocol, the authentication
mechanism is supported by a monitoring component.
The component which exists in database server,
constantly monitors the synchronized secret
information between RFID tag and reader. This
protocol is argued to provide more secure
communication mechanism since the communication
between tag, reader and database is mutually
authenticated and constantly monitored. In addition,
the protocol also supports the low-cost non-volatile
memory of RFID tags. However, it also has limitation
since it still needs the back-end database support.
Table 1. Comparison of all RFID authentication
protocols with hash chain method.
As can be seen in table 1, all protocols being studied
are vary in terms of the way of using hash chain
method but focus on the same objective that is
providing better privacy mechanism while maintaining
anonymity .
5. Conclusion
RFID authentication protocols in this study provide
privacy and anonymity. Hash chain method is used in
these RFID authentication protocols in various ways a
unique solution for security and privacy problems of
RFID technology. As a result, while problems in
particular cases can be addressed, other problem is
arising. Therefore, it can be concluded that recent
RFID authentication protocols with hash chain failed
to satisfy an integrated security and privacy solutions
for RFID.
Based on the findings, we recommend future study
in this area to focus on a level such as developing a
framework for RFID authentication model. The
framework will be useful for researchers as a
foundation for collaborative research in the future for
integrated RFID authentication solutions.
6. References
[1] A, Juels, “Minimalist Cryptography for RFID Tags,” ,
in Blundo, C., Cimato, S. (eds.) SCN 2004. LNCS, vol.
3352, Springer, Heidelberg, 2005.
[2] B, Violino, “Leveraging Internet of Things,” RFID
Journal November/ December, 2005, 1-2.
[3] D, Henrici, and P. Muller, ‘‘Hash-based Enhancement of
Location Privacy for Radio-Frequency Identification
Devices using Varying Identifiers, ‘‘ in Proceedings of
Workshop on Pervasive Computing and
Communications Security, 2004.
[4] D, Molnar and D. Wagner, ‘‘Privacy and Security in
Library RFID Issues, Practices, and Architectures,’’ in
ACM Conference on Computer and Communication
Security, 2004.
AUTHOR Hash Chain Privacy Anonymity
Ohkubo Yes Yes Yes
Weis Yes+PRNG Yes Yes
Molnar Yes No Yes
Henrici Yes Yes Yes
Avoine Yes Yes Yes
Dimitriou Yes+PRNG Yes Yes
Rhee Yes+PRNG Yes Yes
Lee Yes Yes Yes
Lee Yes+PRNG Yes Yes
Han Yes Yes Yes
563
563

[5] G. Avoine, P. Oechslin, “RFID Traceability: A
Multilayer Problem,” Financial Cryptography, 2005.
[6] K. Rhee, J. Kwak, S. Kim, D. Won, “Challenge-
response based RFID authentication protocol for
distributed database environment, ” International
Conference on Security in Pervasive Computing SPC
2005, pp. 70-84, 2005.
[7] Lamport, “Password Authentication with Insecure
Communication”, Communications of the ACM vol. 24,
no.11, pp 770-772, 1981.
[8] M. Ohkubo, K. Suzuki, and S. Kinoshita,
‘‘Cryptographic approach to privacy-friendly tags,’’
RFID Privacy Workshop, 2003.
[9] M.Langheinrich and R.Marti, “Practical Minimalist
Cryptography for RFID Privacy,” IEEE Systems
Journal, vol. 1, no. 2, Dec 2007.
[10] P.P.Lopez, J.C.H. Castro, J.M.E. Tapiador, and
A.Ribagorda, “RFID Systems: A Survey on Security
Threats and Proposed Solutions,” IFIP 2006, PWC
2006, LNCS 4217, pp. 159–170, 2006.
[11] R. Want, Enabling Ubiquitous sensing with RFID,
Computer 37 (4), 2004, pp. 84-86.
[12] S. Han, T.S. Dhillon, and E. Chang, “Anonymous
Mutual Authentication Protocol for RFID Tag Without
Back-End Database,” MSN 2007, LNCS 4864, pp. 623--
-
632.
[13] S. Han, V. Potdar, and E. Chang, “Mutual
Authentication Protocol for RFID Tags Based on
Synchronized Secret Information with Monitor”,
ICCSA 2007, LNCS 4707, pp. 227 – 238, 2007.
[14] S. Lee, H. Lee, T. Asano, and K. Kim, “Enhanced RFID
Mutual Authentication Scheme based on Synchronized
Secret Information”, AUTO-ID Labs White Paper,
WPHARDWARE 032, 2006.
[15] S.A. Weis, S.E. Sarma, R.L. Rivest, D.W. Engels,
“Security & Privacy Aspects of Low-Cost Radio
Frequency Identification Systems, ”Security in
Pervasive Computing, LNCS no. 2802, pp. 201-212,
2004.
[16] S.E.Sarma, S.A.Weis, and D.W.Engels, “RFID systems,
security and privacy implications,” in Technical Report
MIT-AUTOID-WH-014, AutoID center, MIT,
Cambridge, 2002.
[17] S.L. Garfinkel, A.Juels and R. Pappu, “RFID Privacy:
An Overview of Problems and Proposed Solutions,”
IEEE Security and Privacy May 2005, pp. 34-43.
[18] S.M.Lee, Y.J.Hwang, D.H.Lee, and J.I.Lim, “Efficient
Authentication for Low-Cost RFID Systems, “ in
International Conference on Computational Science and
Its Applications, pp. 619–627, May 2005
[19] T. Dimitriou, “A Lightweight RFID Protocol to Protect
against Traceability and Cloning Attacks,” in
International Conference on Security and Privacy for
Emerging Areas in Communication Networks,
September 2005.H. Poor, An Introduction to Signal
Detection and Estimation. New York: Springer-Verlag,
1985, ch. 4.
[20] J. Curtin, R. Kauffman, and F. Riggins, “Making the
‘MOST’ out of RFID technology: A research agenda for
the study of the adoption, usage and impact of RFID,”
Information Technology and Management, vol. 8, no. 2,
87–110. 2007
[21] R. Das, “RFID Tag Sales in 2005—How Many and
Where,” DTechEx Ltd., 2005.
[22] C. Heinrich, RFID and Beyond, Wiley, Indianapolis,
2005.
[23] H. Knospe and H. Pohl, “RFID Security,” Information
Security Technical Report, vol. 9, issue 4, pp 39-50, Dec
2004
564
564

A Survey Of RFID Authentication Protocols Based On Hash-Chain Method

More Related Content

Similar to A Survey Of RFID Authentication Protocols Based On Hash-Chain Method (20)

More from Luz Martinez (20)

Recently uploaded (20)

A Survey Of RFID Authentication Protocols Based On Hash-Chain Method