Smart Client Security

Smart Client Security

The smart client architecture does not depend on a gateway for protocol conversion, so it does not suffer from the WAP gap. However, these applications do have security issues that must be addressed. Anytime data is available outside of corporate firewalls, security mechanisms are required to protect sensitive information. With a smart client architecture, it is possible to provide end-to-end security for your enterprise data. This goes beyond what is currently capable with many thin client solutions.

The main areas of security concern for smart client applications include user authentication, encryption of the client data store, and transport-level security. We will take a look at each of these in turn.

User Authentication

Smart client applications store data directly on the device, much like a client server desktop application does on a PC. To restrict access to this data, user authentication is required. A username/password combination is the minimal level of authentication that should be implemented. The password used should not be stored anywhere on the device, as this would jeopardize the system security. Commonly, this form of authentication is implemented as a check between a userid/password stored within the data store against the userid/password typed in by the user. This usually results in a machine-code jump if the comparison is successful, and, unfortunately, this kind of application can be hacked to always jump, thereby giving the hacker access to the data whenever he or she uses a cracked application. For a better implementation, refer to the Data Store Security section, which follows.

However you implement user authentication to the device and its data, it should not automatically authenticate the user to the enterprise server's data. At this level, a second form of authentication should be implemented, usually one more sophisticated, such as a VPN or digital certificate. In this way, an enterprise can minimize the amount of data that can be accessed by unauthorized users. They will be able to view the small amount of data stored locally, but be unable to update or retrieve any of the enterprise data.

It is also a good idea to take advantage of the security offering of the mobile operating system. All of the leading operating systems provide a mechanism to lock the machine, requiring users to be authenticated before they can gain any device access at all. This would provide a third layer of authentication and serve as a deterrent for someone who may find a lost device.

Data Store Security

With smart client applications, corporate data is stored locally on mobile devices. This data requires protection from unauthorized access, just as other parts of a mobile solution do. In many cases, requiring users to be authenticated before accessing the data is one step to securing this data. Another step is to encrypt the data store itself, making it impossible to view without providing the proper identification, ideally in the form of a digital certificate.

Implementing both authentication and encryption in a single process is the best way to ensure the data remains confidential. The data store can be encrypted using the password as the seed to a symmetric key algorithm. In this way there is no single check to gain access to the application, as all data being returned from the data store will be decrypted using the password.

The encryption should be strong enough so it cannot be easily broken; 128-bit security is not uncommon. This high level of security comes at a price, however: Every time data is added or retrieved, it has to go through the encryption algorithm. This could potentially have a significant negative impact on performance, especially on devices with limited computing power. Also, if for some reason the encryption key is lost, there is no way to access the data without breaking the key, which is computationally infeasible.

If the performance penalty of strong encryption is deemed to be too high, a weaker form of protection, such as data obfuscation, could be used. Obfuscation can scramble the data so it is not viewable by a text-viewing tool. It does, however, not provide nearly the level of security that strong encryption does, but it may be enough for some types of data. Obfuscation has little or no impact on overall performance.

The leading mobile database vendors, including iAnywhere Solutions, provide built-in encryption technologies for their products. If another form of data storage is being used, such as Palm DB or a custom solution, the developer should ensure that data encryption is implemented in the solution. Many of the mobile operating systems provide cryptography libraries to help with this process.

Transport-Level Security

At the transport level, data encryption is required to secure the enterprise data being synchronized. Whether you are using a packaged synchronization solution or building one in-house, the synchronization may be the most important part of the application to secure. Fortunately, there are many encryption products available to provide this security. Companies including Certicom and RSA provide products that can be used to encrypt nearly any type of data being transferred to and from mobile devices. Many of the smart client application vendors include 128-bit data encryption with their solutions. In this way, you can be ensured that the data being transferred over public networks is private from the time it leaves the device to the time it reaches the enterprise server.

Along with encryption, using a strong form of authentication, such as digital certificates, is recommended. In addition, try to keep the firewall around your corporate data as secure as possible; don't open any ports that are not absolutely required by your synchronization server.