Comparison of DNSSEC and DNSCurve securing theObject Name Service (ONS) of the EPC Architecture FrameworkRosenkranz, Demian, University of Applied Sciences Bonn-Rhein-Sieg, 53757 Sankt Augustin, GermanyDreyer, Mark, University of Applied Sciences Bonn-Rhein-Sieg, 53757 Sankt Augustin, GermanySchmitz, Patrick, University of Applied Sciences Bonn-Rhein-Sieg, 53757 Sankt Augustin, GermanySchönborn, Johannes, University of Applied Sciences Bonn-Rhein-Sieg, 53757 Sankt Augustin, GermanySakal, Peter, University of Applied Sciences Bonn-Rhein-Sieg, 53757 Sankt Augustin, GermanyPohl, Hartmut, University of Applied Sciences Bonn-Rhein-Sieg, 53757 Sankt Augustin, Germany
Using the Electronic Product Code (EPC) in the future mostly stored on a Radio Frequency Identification (RFID)-chip,it is possible via e.g. the ONS of the EPC Architecture Framework to distinguish each item worldwide and to trace itback in the supply chain to the producer and furthermore to the subcontractors. The paper describes the comparisonof two mechanisms with different security goals to improve the trust level of ONS: DNSSEC and DNSCurve. DNSSECenables integrity and authenticity - DNSCurve additionally enables confidentiality and a higher availability. The necessarymanpower to install DNSCurve is much lower compared to DNSSEC.
The previously mentioned example of the product Viagra Rillustrated on this framework outlines the process involved
The project Trusted EPC Administration (TEA)1 has been
components of the framework. In this case the starting
working on the problems and challenges discussing the
point in the figure would be the subscriber (customer, con-
trusted global tracking of products along the supply chain
sumer). A consumer owns a product with an unique EPC
since 2009. Last year the team of TEA published a pa-
stored on a RFID-chip. Now the consumer checks the au-
per  which explained and rated the options to increase
thenticity of his product using a terminal in the pharmacy.
the security level in the RFID based supply chain. In this
Using a RFID-reader he scans the EPC of his product and
paper the focus is the comparison of two possible DNS
starts sending a query to the ONS via the terminal. Trusted
security extensions. The following scenario has been se-
operating environment of the terminal i.e. protecting from
cured: A customer purchases a small bottle of an often
radio frequency emission is assumed. The ONS receives
faked medicine (e.g. Viagra R ) in a pharmacy and wants
the EPC and looks for the related EPCIS of the manufac-
to verify its originality immediately. He presents the bot-
turer. The terminal receives the address of the EPCIS and
tle to a RFID-reader inside the pharmacy, which sends the
contacts the EPCIS directly with a query containing the
acquired data using the internet to the Object Naming Ser-
EPC of the product. Now the EPCIS of the manufacturer
vice (ONS), Discovery Service (DS) and EPC Information
can check whether the requesting user at the terminal is a
System (EPCIS). First of all the customer asks for confi-
certain consumer, merchant, supplier, partner, anonymous
dentiality of the communication (his name etc.), further-
etc. and as a result the EPCIS sends the specific informa-
more he asks for anonymity against the producer and is
tion for the user back to the terminal. Eventually the con-
interested to get an answer with integrity. The producer
sumer gets the information whether the EPC of his product
asks for authenticity because he doesn’t want to answer to
is valid or a fake. To allow anonymous requests, not every
counterfeiters spoofing correct product numbers (EPC).
consumer must has a certificate, but in this case the con-sumer has only limited EPCIS functionality - according to
Every interface marked as a (optional) security service and
To allow tracking of products storing an unique EPC, an
every communication path between two incident security
open and supplier-neutral architecture which provides a
services is a possible attack surface and must be provided
worldwide and cross-company solution is necessary. The
with suitable services which secure the communication and
EPC Architecture Framework (Figure 1) provides a plat-
raise the resistance against attacks . By ACP the pro-
form independent configuration of hardware, software and
ducer must be enabled to configure his EPCIS to only send
approved information to a subscriber. However, for theONS itself an ACP is not necessary, as the ONS owns noinformation except the address of the producer. This en-
1 Sponsored by the German Federal Ministry of Education and Research No. 01 IS
ables the consumer to start an anonymous query to the
Figure 1 Security Services in EPC Architecture Framework
ONS and prevents the connection between customer and
The implementation of the ONS inside the EPC Archi-
tecture Framework is based on DNS. On account of thisat least the security goals confidentiality, authenticity and
integrity have to be achieved by the ONS. As DNS itselfdoes not suffice the demands of the TEA project (confiden-
The Query Front-end of the prototype of TEA is a graphi-
tiality, integrity, availability, authenticity/non-repudiation),
cal web-based user interface. Authorized subscribers have
several technologies to improve the security standard of
to validate themselves towards the EPCIS by certificates
generated by a Public Key Infrastructure (PKI)  in orderto receive specific information about a product provided
Table 1 shows the currently most important technologies
with an EPC. This allows a software-based solution for the
and their representative protective goals.
The Object Name Service (ONS) works like the well-known
Domain Name System (DNS). It starts with the resolution
of a query, in this case for an EPC, and ends with the an-
swer from the resolution in form of an address of an EP-
CIS related to the EPC. The essential difference compared
to the DNS is that the ONS owns in each case only oneaddress to a possible query based on an EPC and sends
it as an answer. Because the functionality and the require-
ments of both ONS and DNS are identical, the use of DNS-
AT –> Authenticity, CF –> Confidentiality, IN –> Integrity
In the following, Domain Name System Security Exten-
sions (DNSSEC) and DNSCurve will be discussed.
In the past two years, the Domain Name Service (DNS)
was repeatedly attacked mainly by cache poisoning  -a denial of service - accomplishing attacks .
DNSSEC guarantees the protective goals authenticity andintegrity for ONS information. Additional to the known re-
source records (RR) DNSSEC uses specific resource records.
adoption and maintenance. An error-prone migration to
DNSSEC applies an asymmetric pair of keys (zone sign-
DNSSEC might jam whole zones in result.
ing keys) to each secured zone. Each RR will be signedusing the private zone key. The signature of one or more
Until today many home office and small office routers are
RR of the same type will be deposited in a signature re-
not able to compute DNSSEC queries larger than 512 Byte
source record. DNSSEC is capable to use the algorithms
(UDP) and simply drop them without notifying the user
RSA2/Secure Hash Algorithm 1 (SHA-1), Digital Signa-
. This is a limiting factor for the integration of DNSSEC
ture Algorithm (DSA)/SHA-1 and RSA/Message-Digest
in a network like the EPC Architecture Framework.
Algorithm 5 (MD5). MD5 is not longer recommended be-cause of the insecure MD5 hash algorithm .
For this is a known problem a testbed has been establishedin Germany to promote the acceptance of DNSSEC. It is
The implementation of DNSSEC required significant changes supported by "Deutsches Network Information Center"in the configuration of the nameserver. Larger compounds
(DENIC) - the manager of top-level domain for Germany
of the zone file have to be changed or complemented. Among
these comes the integration of the key signing keysand thezone signing keys.
DNSCurve is currently the most important competitor ofDNSSEC. DNSCurve allows an easy integration because
of its black box architecture and requires only a small amount
The product suite DNSCurve  is based on the spe-
of maintenance costs. Also small office and home office
cial elliptic curve Curve25519. DNSCurve can be used to
routers can handle the encrypted content of the DNSCurve
achieve integrity, authenticity and confidentiality for ONS
information. By using DNSCurve the content of trans-mitted and received data packets are neither unrecognized
There is only a prototype implementation of DNSCurve
modified nor readable for attackers using encryption and
available at the moment. A date for a stable version of
DNSCurve is not known. The release of a stable version ofDNSCurve is mandatory for its use within the EPC Archi-
Only a patched forwarder on the server side and a patched
DNS-cache on the client side is needed (Figure 2). Thesecomponents have to be integrated between DNS server and
client to handle the incoming and outgoing requests.
Both DNSSEC and DNSCurve ensure the protective goalsauthenticity and integrity. In contrast to DNSCurve, DNS-SEC does not provide confidentiality. In a network likeEPC Architecture Framework that communicates sensitivedata, confidentiality is essential . The consequence is,that ONS secured by DNSSEC can’t serve the confiden-tiality for the customer (subscriber). This gets emphasisedby the example of the customer who wants to buy Viagra R .
The customer has to be anonym against the manufacturer.
Furthermore no third party may get the chance to attainthese information.
Contrary to DNSCurve DNSSEC requires the zone sign-
ing keys (ZSK) and key signing keys (KSK) to be updated
in a certain interval. In this context the KSK is responsiblefor the proof of identity. The renewal of the KSK is critical
Encryption and the key sharing process of DNSCurve is
as a breach of security might cripple a whole zone .
known as Two Key Communication  . Addition-ally - as for asymmetric encryption common - hash keys
Another important aspect of DNSSEC is the usage of the
will be compared to ensure integrity.
RSA-1024 as encryption of the root zone , which - in
consideration of major botnets  - does not provide suf-ficient trust level. RSA-1024 might be already broken (i.e.
by larger companies or botnets) ; but until today thereis no scientific verification. Using DNSSEC the EPC Ar-
Two reasons for the slow circulation of DNSSEC are the
chitecture Framework might be compromised.
high administrative effort and the involved costs within the
2 stands for Rivest, Shamir and Adleman who first publicly described it
DNSCurve uses Curve25519 which is efficient and applies
119 bytes (100%) 341 bytes (287%) 304 bytes (255%)
Table 2 Average size of response packets 
a high security level: A similar level of security is possiblewith 3000-bit RSA, but encryption and authentication with3000-bit RSA is not fast enough to handle modern DNS
loads and would require much more space in DNS packets
To ensure not only security but also scalability in the EPC
The calculation of DSA and ECC keys is significant faster
Architecture Framework dealing with enormous amounts
as the calculation of RSA keys. DSA and ECC needed a
of traffic, a high performance encryption algorithm has to
similar length of time to compute the keys, but a RSA and
be applied. Using DNSSEC increases the size of the re-
DSA key length of 1024 Bit corresponds to an ECC key
sponse packets enormously because of the additional Re-
length of 160 Bit at comparable trust level. ECC Curve
source Records (RR) sent. To illustrate the difference in
prime 192v1 has been used to compute the ECC equiva-
size, different signed and unsigned DNS requests were sent
lent. Therefore the ECC algorithm outperforms RSA and
to the server. The names of the requested domains had an
DSA by a factor of almost 10 . In view of the perfor-
average length of ten characters. The zone signature had a
mance the use of DNSCurve in ONS as a component of the
length of 1024 Bit. Table 2 illustrates the average size of
EPC Architecture Framework is recommended instead of
The size of DNSCurve packets is larger in comparison to
standard DNS packets. During the sample requests, sizeof DNSCurve packets rose by 255%. Using DNSSEC in-
The use of DNS was not to be recommended up to now if
creases packet size by 287%. It remains to note that DNS-
a high security level had to be guaranteed e.g. in the EPC
Curve achieves more protection goals (cf. table 1) then
Architecture Framework. Therefore, this paper has been
DNSSEC while getting along with smaller packet size. This
compared two possible solutions for securing DNS. Table
can be traced back to the shorter encryption keys of DNS-
4 summarizes the main findings from the comparison of
Curve which results of the use of Elliptic Curve Cryptog-
raphy (ECC). Furthermore DNSCurve and standard DNSdo not generate traffic when requesting a non-existing do-
main, while DNSSEC does (cf. table 2) .
According to Prof. Bernstein - the originator of DNScurve
- about 50 billion DNS packets are sent within the .com
zone each day. The application of DNSSEC would in-
crease the anyway enormous traffic significant. This is
counted to the 287% increased packet size compared to
DNS and additionally sent response packets when request-
ing non-existent domains . Using DNSSEC to secure
the ONS of the EPC Architecture Framework which han-
dles world wide requests would also increase the traffic sig-
The advantage in performance of DNSCurve is shown intable 3. 10.000 pairs of keys have been computed, using
DNSSEC does not implement confidentiality. The use of
RSA, DSA and ECC. Table 3 shows the mean time mea-
RSA 1024 is insecure and common routers might not be
sured in seconds needed to compute the belonging keys. To
able to process encrypted packets. Using DNSCurve to
minimize discordant values, three different CPU architec-
ensure the security goals authenticity, integrity and confi-
tures Intel Centrino Duo, Athlon X2 and Intel i7 920 were
dentiality enables the domain name service in the future to
used to calculate the mean time for computing the keys.
be used in environments where a high security level has tobe guaranteed, i.e. ONS.
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