06-07-2012, 01:47 PM
MOBILE DATA SECURITY
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Abstract
Every day, mobile workers take laptop computers and handheld devices outside of the organizations secure environment. Cell phones, PDAs, laptop computers, and other devices make it convenient to access information anywhere. However, the potential for confidential information to be exploited on these devices, the ability to access the corporate network from outside the firewall, as well as the susceptibility of these devices to loss and theft creates security risks that must be addressed in order to protect the privileged data. This paper discusses issues we have to consider when designing and implementing procedures to protect the mobile data, including the security problems of interception of data transmissions, authentication of users, rogue access to data, and lost devices. It also discusses how the security strategy can address these problems.
1. Introduction
Mobile devices, such as laptops and PDAs, make it possible for workers to access information anywhere. However, enhanced mobility means data can travel outside the boundaries of LAN firewall. As more workers use mobile devices to access privileged data outside organization's secure environment, security strategy needs to address ways of managing and securing the mobile devices that access and store privileged data. Making data available to all authorized users whenever they require it makes data more valuable. The use of mobile devices to access information has made it easier for users to be more productive by making data available outside the enterprise. But mobile computing necessitates the exchange of confidential data over public networks, rather than over wired networks inside the enterprise. There is also the risk of data being intercepted over wireless networks. With mobile computing, it is more difficult to identify the entity that is accessing the enterprise information than it is to identify the entity over a traditional wired network.
2. Implementing Security
Procedures
When thinking about mobile data security, there is no perfect solution. Security is about reducing risk, not eliminating it. In order to establish security procedures to protect the data, there are several questions that we can consider. The answers to these questions will vary from organization to organization, but they can help us understand what security measures will best meet our needs.
Five common problems encountered with mobile data are:
• interception of data transmissions
• authentication of users
• rogue access to data
• lost devices
• Protecting existing security investments
3. Solving mobile data security
Problems
It is important to find and address the weakest link in the security system. Addressing an area of weakness could include encrypting data on the device, encrypting data communications, password-protecting devices, incorporating user login mechanisms, or implementing device security policies. Now, let's examine each of the five mobile data security issues.
3.1. Protecting data transmissions
When data is being transmitted, we want to ensure that it is secure from end to end. There are many places where our data may be intercepted: in thin-client, browser-based applications, e-mail, voice, data synchronization, client/server communications, or messages and alerts. Secure data transmission has the following features:
• Confidentiality Communications should remain private.
• Integrity No one should be able to change the data, regardless of whether they are able to see it.
• Authentication we have to ensure that we know who we are communicating with on the other end and avoid a man-in-the-middle attack. Clients connecting to the enterprise system need to know that they are communicating with the correct server. We also want to ensure that only authorized clients are communicating with the server. In order to protect the data, we should ensure that there is end-to-end encryption of the data, from the remote device to behind the corporate firewall.
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3.1.1. Communication architecture
The communication stack isolates the different functions needed for reliable data transfer. Each layer of a protocol stack treats information passed to it by the layer above merely as data, labeling that data in such a way as to be identified and deciphered by the equivalent layer on the other computer. Only the physical layer is responsible for actually placing data onto the wire or over the air—all other layers provide some well-defined level of functionality, such as error detection, correction, and encryption [1] and so on. Figure 2 shows a typical communication stack and how adding security affects the architecture.
When an application needs to encrypt the data that it is sending, it is necessary to have a security protocol to establish a secure connection. Security protocols are a negotiation (often called a handshake) of security parameters required to securely establish an encrypted communication session. Generally, they also provide authentication. Examples of security protocols are Transport Layer Security (TLS) and Secure Sockets Layer (SSL). [4]
Transport-layer security is important whenever communications must travel over a public or private network where transmissions could be intercepted by an attacker. Using transport-layer security
Figure 1
Communication stack Communication stack
Without encryption with encryption
Client
Application
Database
Server
TL
S
Application
Figure 2
Transport
Layer (TCP)
IP Layer
Physical
Hardware
Encryption
Security Protocol
Application
Transport
Layer (TCP)
IP Layer
Physical
Hardware
allows a client application to verify the
.1.2. Public-key cryptography
es use of
A message encrypted with the
c
incorporate randomness designed to be truly
igital certificates
digital certificate is an electronic
a person or entity
gital signatures, to prevent
the certificate
digital signature [5] provides a means to
has been altered.
identity of a server. Clients can ensure that they communicate only with servers they trust
3
Public-key cryptography [3] mak
mathematical systems that work with pairs of very large, associated numbers. These numbers, called keys, have particular properties. Each key can be used to encrypt information. Once encrypted, these messages can be decrypted only using the matching key. One of the keys, called the public key, is published in a public forum and can be used to encrypt information that is sent to the owner of the public key. The owner keeps the second key, called the private key, secret.
public key an be decrypted only by using the private key. Since the public key is published, anyone can create a message that only the private key owner can read. In addition, anyone who knows the public key can decrypt a message encrypted with the private key. In this way, the owner of the private key can "prove" that they know the private key by using it to create a message that can be decrypted using the associated public key. It is essential that the private key cannot be found easily through knowledge of the public key. The ease with which the private key can be derived from the public key is often associated with the strength of the cryptosystem and the size (in bits) of the public key. Another aspect of the private key is that it must be difficult to guess. The generation of high-quality private keys must unpredictable. Algorithms that use public key cryptography include RSA, Diffie-Hellman, and Elliptic Curve Cryptography (ECC). 3.1.3. D
A
document that identifies
and contains a copy of their public key. Each certificate includes a public key so that anyone can communicate securely with the person or entity by encrypting information with this public key. Digital certificates conform to a standardized file format that contains the following information: 1. Identity information, such as the name and address of the certificate owner
2. Public key 3. Expiry date
4. One or more di
modification of
3.1.4. Digital signatures
A
detect whether a document
A digital signature is also used to verify that the certificate represents the person or company that it claims to represent. For example, if you receive a certificate from the ABC Company that is signed by VeriSign or another certificate authority, then you can be confident that you are communicating with the real ABC Company if you trust the certificate authority. A digital signature is a cryptographic operation created by calculating a value, called a message digest, from the document information, or in the