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Anonymity communication VPN and Tor: a
comparative study
To cite this article: E Ramadhani 2018 J. Phys.: Conf. Ser. 983 012060
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1234567890 ‘’“”
International Conference on Mathematics, Science and Education 2017 (ICMSE2017) IOP Publishing
IOP Conf. Series: Journal of Physics: Conf. Series 983 (2018) 012060 doi :10.1088/1742-6596/983/1/012060
Anonymity communication VPN and Tor: a comparative
study
E Ramadhani1,*
1Department of Industrial Engineering, Faculty of Industrial Technology, Universitas
Islam Indonesia
*Corresponding author: erika@uii.ac.id
Abstract. VPN and Tor is a technology based on anonymity communication. These two
technologies have their advantage and disadvantage. The objective of this paper is to find the
difference between VPN and Tor technologies by comparing their security of communication
on the public network based on the CIA triad concept. The comparative study in this paper is
based on the survey method. At last, the result of this paper is a recommendation on when to
use a VPN and Tor to secure communication
1. Introduction
Anonymity communication is a communication that provides a hiding services on the Internet. The
aim is to secure the communication line from an authorized user. Virtual Private Network (VPN) and
The onion routing (Tor) are examples of anonymity communication. VPN and Tor have the same
tunneling model communication, and they are also using encryption technology to reach the integrity
of data. VPN usually implemented in an enterprise, while Tor tends to be used in a darknet side of the
Internet.
The problem is although VPN and Tor have a similarity in their purpose, we cannot implement it
arbitrarily. Inappropriate use may cause a fatal error in a network security system. We need to know
on when to use between VPN and Tor; we need to do a comparative study between VPN and Tor
regarding the security of communication. The comparative study is based on the survey method. The
comparison covers the technology that has been used, the vulnerability of system so we can see the
advantage and the disadvantages of the system, and the comparison based on the CIA triad concept in
network security.
The result of this paper may be used as a recommendation when to use a VPN and Tor to get a
secure communication based on anonymity communication.
2. Theoretical Background
2.1. Virtual Private Networks (VPN)
VPN is a network technology for securing communications lines between members or groups that
together use public communications infrastructure that provides privacy services to communication
lines using security and tunneling protocols. Characteristic of the VPN itself is the use of tunnels that
provide security privacy to the communication path between nodes. VPN technology is usually called
2
1234567890 ‘’“”
International Conference on Mathematics, Science and Education 2017 (ICMSE2017) IOP Publishing
IOP Conf. Series: Journal of Physics: Conf. Series 983 (2018) 012060 doi :10.1088/1742-6596/983/1/012060
VPN tunneling. Tunneling is a network technology that encompasses one type of protocol that
contains packets and datagrams from different protocols [1]. For example, a Windows VPN uses
point-to-point tunneling (PPTP) protocol package to complement and transmit private network traffic
such as TCP / IP over public networks such as the Internet.
2.2. The onion routing (Tor)
The Onion Routing (Tor) is a computer network technology that uses the routing process to several
hops to get to the destination. During the routing process to some hops, the encryption process occurs.
The encryption process is done three times by the hops that passed. Tor provides the type of data
delivery security from the anonymity side of the communication path. The client will be connected to
the destination by passing through 3 relays namely entry node, middle relay, and exit relay. These
three relays will then perform the process of encryption of the data [2].
2.3. CIA Triad Concept
Security components in the computer network system consisting of three kinds of confidentiality,
integrity, and availability commonly abbreviated to the CIA. Essential components related to data
communications security are confidentiality and integrity. Confidentiality is usually associated with
data confidentiality. Data or information can only be read by an authenticated user. Usually, the
implementation is using cryptographic techniques in the process of sending data. Two things to
consider in confidentiality, are data confidentiality and privacy. Integrity relates to the authenticity of
data that already transmitted, requires unmanipulated data. While the availability associated with the
provision of services to access data or information by the user. Systems should always be available to
provide services to users [3]. Two important things to note on this point are data integrity and system
integrity.
3. Methods
This research method is done by doing a comparative review of previous research papers that talk
about VPN and Tor. To compute the system against VPN and Tor, it is necessary to consider the
security characteristics of data communications that have been discussed previously, namely
confidentiality, integrity, and availability. The research flow is shown in Figure 1.
4. Result and Discussion
The result of security comparison of data communication between VPN and Tor is divided into two
categories: based on security components and based on weaknesses in topology and technology used.
Figure 1. Flowchart of research
Start Data Collection Data Processing
Analysis and
Comparative
Study
Result Recomendation
End
3
1234567890 ‘’“”
International Conference on Mathematics, Science and Education 2017 (ICMSE2017) IOP Publishing
IOP Conf. Series: Journal of Physics: Conf. Series 983 (2018) 012060 doi :10.1088/1742-6596/983/1/012060
The following is the result of comparison of data communication security between VPN and Tor,
shown in Table 1.
Table 1. Comparison between VPN and Tor based on CIA triad concept
Confidentiality
Integrity
Availability
VP
N
Tunneling encryption
SSL/TLS and digital
signature
Integrity check
Conventional authentication
Using AH and ESP
protocol [4]
Good performance by
using sustainable ping
process [5]
Tor
Three hops tunneling
encryption
Negotiation secret key
Using TLS/SSLv3 Protocol
Using SOCKS proxy
Using symmetric crypto
Sustainable
communication by
using relay
Low latency
In this section, the discussion will cover the differences between VPN and Tor based on
communication security from CIA components. The subject matter will be based on the table 2 of
relationships between Security Services and Mechanisms written by Stallings, W.
Table 2. Relationship between security services and mechanisms
Service
Enciphermen
t
Digital
Signature
Data
Integrity
Authenticati
on Exchange
Routi
ng
Control
Confidentialit
y
Y
Y
Data Integrity
Y
Y
Y
Availability
Y
Y
4.1. Confidentiality
Confidentiality is one component of system security that maintains the confidentiality of a data. In this
section includes two concepts of data confidentiality and privacy. In the data confidentiality that is
concerned is the protection of data from access from outside that is not authorized. In the VPN, the
aspect of confidentiality is shown in the use of tunneling encryption. Encryption tunneling on a VPN
is an aspect that encrypts all data passing through its path. This encryption technology allows data
confidentiality to be maintained. The existence of this encryption technology also prevents an
unauthorized user from being able to read the contents of the transmitted data, even though the
intruder can intercept the data. Tunneling technology used by the VPN is the routing process is done
directly from the source to the destination. While the technology used by Tor, the encryption process
is done by three layers. This is done to avoid sniffing the data contents by the attacker. Also, to
achieve the goal of the Tor is anonymous communication. Tunneling used in Tor is a routing process
done by passing through 3 relays [6].
4.2. Integrity
This section discusses how VPN and Tor can maintain data integrity. On VPN there are three types of
protocols used for site-to-site connections: PPTP, L2TP over IPSec, and IPsec tunnel mode. In PPTP-
VPN the technology does not provide a guarantee of data integrity. PPTP also does not provide Public
Key Infrastructure (PKI) to check computer certificates [7]. While on the IP-Sec VPN there is a
4
1234567890 ‘’“”
International Conference on Mathematics, Science and Education 2017 (ICMSE2017) IOP Publishing
IOP Conf. Series: Journal of Physics: Conf. Series 983 (2018) 012060 doi :10.1088/1742-6596/983/1/012060
process of authentication, data integrity and encryption services to protect data from unauthorized
users and possible data modification. The protocols used are Authentication Header (AH) and
Encapsulated Security Payload (ESP). For L2TP is a combination of Microsoft Point-to-Point
Tunneling Protocol (PPTP) and Cisco L2F. Usually, L2TP does not provide encryption technology, so
L2TP is often implemented in conjunction with IPsec. IPSec provides two of key management; they
are Manual Key Management and Automated Key Management. HMAC-Message Diggest 5 (HMAC-
MD5) and HMAC –Secure Hash Algorithm 1 (HMAC-SHA1) is the two popular algorithm in a VPN
gateway that uses for verifying the integrity of data. VPN also uses Diffie-Hellman Group 1 (DH-1) &
Diffie-Hellman Group 2 (DH-2) as an encryption algorithms, but it is not a data integrity algorithms.
OpenVPN is an open source technology that uses OpenSSL encryption libraries and SSL v3 / TLS
v1 protocols. The configuration allows using AES or Blowfish encryption technology [8]. A Hashed
Message Authentication Code (HMAC) is a data integrity algorithm that ensures the integrity of the
message.
Table 3. Vulnerabilities Comparison between VPN and Tor
VPN
Tor
Type of attacks:
VPN – Hijacking
Man – in – the – Middle
Attacks
Type of attacks:
End-to-end attacks
Tagging attacks[9]
Lack of topology:
In many enterprises provided
a connection between
wireless and wired based.
Usually, the Ethernet jack is
open, but 802.1X enabled
authentication. This
condition called the hidden
wireless router (HWR)
vulnerability.
The IP address is not
restricted because ISP could
see it as an exit point.
Lack of topology:
Entry node and exit node is the vulnerable part.
According to [10], Tor exit node is the
vulnerability section. One of many categories of
attack is a malicious exit node modifies
webpages, inserting JavaScript code that
repeatedly connects to a logger server and
sending a distinctive signal along the link. If the
client uses a malicious entry node while
JavaScript is active, the entry node can detect
the signal and attacker can associate the client
using his communication.
We can not trust a relay in the onion network,
one of them maybe can act as an attacker.
In Tor, the integrity of the data draws much criticism and praise. Keep in mind Tor consists of
many relays hosted by volunteers. You can imagine many relays if more hosts are willing to be a node
inside a Tor network. So based on the exposure, the Tor topology will make the data becomes more
difficult to know where it came from and where to go. The encryption technology used is three layers
and passes the path using the TLS protocol. Here is a translation of Tor technology used regarding
data integrity:
Tor uses SOCKS proxy.
Before establishing the inter-node communication circuit, Tor uses Public Key Crypto.
Communication between circuits using Diffie-Helman crypto symmetric.
SIG: a signature of a SHA256 hash and OAEP-MGF1 padding
Tor also uses RSA and Diffie-Helman as an encryption algorithms, these two is not a data integrity
algorithms. In a study conducted by Seongmin Kim et al, they recommended an approach to improve
5
1234567890 ‘’“”
International Conference on Mathematics, Science and Education 2017 (ICMSE2017) IOP Publishing
IOP Conf. Series: Journal of Physics: Conf. Series 983 (2018) 012060 doi :10.1088/1742-6596/983/1/012060
security and privacy on the use of Tor using the Intel SGX they call SGX-Tor. Systems created based
on trusted computing. In a simple Tor topology, key pairs are stored as files, so there is the possibility
of a key leak. SGX-Tor protects cryptographic operations and wraps keys before being stored in a file
[11].
4.3. Availability
The more critical a service or component, the higher level of availability required. Interruptions that
occur in the service will cause the user cannot access the computer resources The assumption is when
a system provides authentication services for a critical application then the system can guard the
against the downtime and unreachable due to malicious actions. Based on table 2, the criteria reaching
the availability of a system is to have data integrity and authentication exchange mechanisms. VPN
and Tor have their data integrity and authentication exchange mechanisms that presented in section
5.2. VPN has their availability in one to one connection line straight from source to destination
without a low latency. While Tor is more slow because of its low latency, but the system is never
going down because the architecture is based on distributed system relay. The two has their advantage
in this section.
Table 4. Advantage and disadvantage between VPN and Tor
Communication
Advantage
Disadvantage
VPN
Fast
More secure than Tor if there
is no log in VPN provider.
Suitable for P2P filesharing
Not secure if the log could see
by VPN provider
IP address is known as exit
point or server
Sometimes not free
Tor
IP address is completely
secret
The topology is based on
distributed network
Free and open source
Not suitable for P2P
filesharing
Inefficient because of the low
latency
As conclution, in this section, we provide a recommendation when to use a VPN and Tor. Before
we are implementing between VPN or Tor, we should know the vulnerability of that two systems. The
vulnerability of VPN and Tor show on table 3. These vulnerabilities based on the type of attacks and
the lack of system topology. VPN is faster than Tor. Tor is very slow because the data is bounced
randomly through manfy relays which could be anywhere in the world. We do not need to trust anyone
while using Tor because it is completely anonymised. For such filesharing activities and streaming
geo-restricted media content, using VPN is better than a Tor. VPN very secure as long as there are no
logs at VPN provider. Tor is always oriented by mafia whistleblower or a dissident living under the
regime. VPN provider knows your real IP address and can see the internet traffic at the exit point but
not in Tor. To see the difference between VPN and Tor, we can see the summarized in table 4 based
on advantage and disadvantage. The use of Tor and VPN depends on how you want to use it.
According to [12] OnionCat is an application that using Tor's hidden services and implemented in a
layer between a client application and the Tor proxy. OnionCat and Tor claimed that it is a new kind
of anonymous VPN.
5. Conclusion
In this paper, we presented the difference between VPN and Tor based on their secure communication.
The purpose of VPN and Tor is very similar, i.e., to maintain internet users' online anonymity and to
6
1234567890 ‘’“”
International Conference on Mathematics, Science and Education 2017 (ICMSE2017) IOP Publishing
IOP Conf. Series: Journal of Physics: Conf. Series 983 (2018) 012060 doi :10.1088/1742-6596/983/1/012060
evade firewalls. The use of VPN and Tor depends on how you want to use it. Each has their
advantages and disadvantages. We can combine it to get more secure communication. One thing to
note is there is no such a thing as a fully guarantee of anonymity. Just use it wisely based on our
necessity.
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