Home > Articles > Operating Systems, Server > Solaris

  • Print
  • + Share This
Like this article? We recommend

Developing Your Own Trust Model

Just as we identified original entity authentication as the first step in establishing trust, we need to identify the starting point for defining a trust model. We have already talked about matching a model to business requirements, but at this point, we will go back an additional step. At the very foundation of trust model development, there should be a basic principle governing acceptable use of both data and processing resources. Sometimes this is referred to as the security stance. A common security principle used by many organizations in the Internet space is that data must be accessible only on a need-to-know basis, and processing resources must be accessible only to those explicitly approved to use them.

This principle would be appropriate for an organization with stringent security requirements, but another organization concerned with attracting customer interest would have a different philosophy about access to at least certain types of data.

With the underlying principle understood, the next step is to gather business requirements. These requirements must be specific to the organization, although they may well be similar to those of other comparable organizations. In many cases, requirements will be determined by legal and regulatory mandates. Perhaps a Service Level Agreement (SLA) will be a determining factor. If there is a requirement for a certain level of performance (such as speed, throughput, or availability), it must be identified, because a security mechanism with a noticeable impact on performance might be unacceptable.

Next, build a threat profile based on a data flow analysis. An example of a data flow analysis is provided below, but the key point here is to catalog threats and vulnerabilities. Some risks are going to be more significant than others and will require greater effort to mitigate. Some may even be judged relatively inconsequential and therefore not cost-effective to address.

In assessing risk, be sure not to focus solely on technical issues. It cannot be stated often enough that good security requires a combination of people, process, and technology. Look for those places where human error or poorly designed processes introduce risk.

Finally, identify security mechanisms to respond to those risks that must be addressed. Response mechanisms may be technical in nature (for example, a firewall), but they may also address the human factor (for example, better training). At this point, a technical solution will likely be identified at a relatively high level (for example, to install a firewall). The choice of the specific firewall to install and the configuration details generally come later in an implementation phase.

Example of a Data Flow Analysis

To illustrate what data flow analysis offers, consider the example of online banking. For the purposes of illustration, the following steps assume the customer wants to view his current account balance, and the bank has already established customer authentication credentials.

  1. The customer initiates a session with bank's server. The protocol governing the session is SSL.

  2. The SSL server dialog is established, which encompasses all of the following steps. (Note that client-side SSL authentication is not performed.)

  3. The customer enters the required information (for example, name, account number, and PIN) on the login screen.

  4. The authentication server validates credentials.

  5. The Web services server presents a welcome and a menu of options the customer can invoke.

  6. The customer's selection of the account query option is passed to the application server.

  7. The application server queries the authorization server to see if the selected option is allowed.

  8. The authentication server returns a response to the application server, based on rules. For this example, it allows the query to be made.

  9. The application server requests the database server to obtain account records.

  10. The database server returns records to the application server.

  11. The application server formats data and passes it to the Web services server for presentation to the customer.

  12. Note that the SSL server has encrypted all session data to and from the customer.

Figure 1FIGURE 1 Data Flow Analysis

In this example, two types of data were processed:

  • Customer authentication information (name, account number, PIN)

  • Customer account information (account balance)

A complete analysis requires examination of the type of data processed at each trust point, identification of the types of threats affecting each trust point, and specification of the appropriate countermeasure.

For the purposes of this example, start by identifying all the different servers involved:

  • SSL server
  • Authentication server
  • Web services server
  • Application server
  • Authorization server
  • Database server

For a seemingly simple request, the sheer number of servers dramatizes the number of communication paths, and therefore trust points, that data flows through. Each of the trust points is also a potential attack point. A security failure of any of these points could have very damaging consequences.

What is the risk of exploitation of a security failure? Presumably, it is very high, because sensitive financial data is at stake. Compromises could lead to disastrous results, such as:

  • Someone other than the account owner gaining access to data

  • Legitimate account owner being presented with more information than should be transmitted

  • Account owner (or someone else) being able to perform unauthorized transactions

Our hypothetical financial institution must have as minimum business requirements (no doubt reinforced by legal and regulatory requirements) the need to protect data confidentiality and integrity.

Trust Model Derived From the Example

Upon completion of a much more thorough analysis of threats, based on data flow analysis, risks, and business requirements, you have the information necessary to determine the appropriate trust model. In the example, to satisfy the requirements for confidentiality, integrity, and non-repudiation, there must be very stringent authentication and authorization mechanisms. Because sensitive data is being transmitted over the Internet, encryption should be required. The trust required is between the customer and the bank. No trust among the various customers using the online banking application is required or even allowed. Based on these facts, a direct trust model should be employed. Because the type of information a customer is allowed to access must be strictly controlled, the trust model incorporates the basic principle: data will be accessible only on a need-to-know basis.

Expressed more formally, our trust model might read something like the following:

  • The security architecture must implement a direct trust model.

  • All users must be identified and authenticated. Trust and authentication can never be implied or assumed.

  • No transitive or assumptive trust can exist between any component of the bank's computing environment and any external system.

  • Entities that are uniquely identified and authenticated may be trusted to access data and resources only on a predefined need-to-know basis.

  • Data transferred over the Internet between the bank and an authenticated user must be encrypted.

  • + Share This
  • 🔖 Save To Your Account

InformIT Promotional Mailings & Special Offers

I would like to receive exclusive offers and hear about products from InformIT and its family of brands. I can unsubscribe at any time.


Pearson Education, Inc., 221 River Street, Hoboken, New Jersey 07030, (Pearson) presents this site to provide information about products and services that can be purchased through this site.

This privacy notice provides an overview of our commitment to privacy and describes how we collect, protect, use and share personal information collected through this site. Please note that other Pearson websites and online products and services have their own separate privacy policies.

Collection and Use of Information

To conduct business and deliver products and services, Pearson collects and uses personal information in several ways in connection with this site, including:

Questions and Inquiries

For inquiries and questions, we collect the inquiry or question, together with name, contact details (email address, phone number and mailing address) and any other additional information voluntarily submitted to us through a Contact Us form or an email. We use this information to address the inquiry and respond to the question.

Online Store

For orders and purchases placed through our online store on this site, we collect order details, name, institution name and address (if applicable), email address, phone number, shipping and billing addresses, credit/debit card information, shipping options and any instructions. We use this information to complete transactions, fulfill orders, communicate with individuals placing orders or visiting the online store, and for related purposes.


Pearson may offer opportunities to provide feedback or participate in surveys, including surveys evaluating Pearson products, services or sites. Participation is voluntary. Pearson collects information requested in the survey questions and uses the information to evaluate, support, maintain and improve products, services or sites, develop new products and services, conduct educational research and for other purposes specified in the survey.

Contests and Drawings

Occasionally, we may sponsor a contest or drawing. Participation is optional. Pearson collects name, contact information and other information specified on the entry form for the contest or drawing to conduct the contest or drawing. Pearson may collect additional personal information from the winners of a contest or drawing in order to award the prize and for tax reporting purposes, as required by law.


If you have elected to receive email newsletters or promotional mailings and special offers but want to unsubscribe, simply email information@informit.com.

Service Announcements

On rare occasions it is necessary to send out a strictly service related announcement. For instance, if our service is temporarily suspended for maintenance we might send users an email. Generally, users may not opt-out of these communications, though they can deactivate their account information. However, these communications are not promotional in nature.

Customer Service

We communicate with users on a regular basis to provide requested services and in regard to issues relating to their account we reply via email or phone in accordance with the users' wishes when a user submits their information through our Contact Us form.

Other Collection and Use of Information

Application and System Logs

Pearson automatically collects log data to help ensure the delivery, availability and security of this site. Log data may include technical information about how a user or visitor connected to this site, such as browser type, type of computer/device, operating system, internet service provider and IP address. We use this information for support purposes and to monitor the health of the site, identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents and appropriately scale computing resources.

Web Analytics

Pearson may use third party web trend analytical services, including Google Analytics, to collect visitor information, such as IP addresses, browser types, referring pages, pages visited and time spent on a particular site. While these analytical services collect and report information on an anonymous basis, they may use cookies to gather web trend information. The information gathered may enable Pearson (but not the third party web trend services) to link information with application and system log data. Pearson uses this information for system administration and to identify problems, improve service, detect unauthorized access and fraudulent activity, prevent and respond to security incidents, appropriately scale computing resources and otherwise support and deliver this site and its services.

Cookies and Related Technologies

This site uses cookies and similar technologies to personalize content, measure traffic patterns, control security, track use and access of information on this site, and provide interest-based messages and advertising. Users can manage and block the use of cookies through their browser. Disabling or blocking certain cookies may limit the functionality of this site.

Do Not Track

This site currently does not respond to Do Not Track signals.


Pearson uses appropriate physical, administrative and technical security measures to protect personal information from unauthorized access, use and disclosure.


This site is not directed to children under the age of 13.


Pearson may send or direct marketing communications to users, provided that

  • Pearson will not use personal information collected or processed as a K-12 school service provider for the purpose of directed or targeted advertising.
  • Such marketing is consistent with applicable law and Pearson's legal obligations.
  • Pearson will not knowingly direct or send marketing communications to an individual who has expressed a preference not to receive marketing.
  • Where required by applicable law, express or implied consent to marketing exists and has not been withdrawn.

Pearson may provide personal information to a third party service provider on a restricted basis to provide marketing solely on behalf of Pearson or an affiliate or customer for whom Pearson is a service provider. Marketing preferences may be changed at any time.

Correcting/Updating Personal Information

If a user's personally identifiable information changes (such as your postal address or email address), we provide a way to correct or update that user's personal data provided to us. This can be done on the Account page. If a user no longer desires our service and desires to delete his or her account, please contact us at customer-service@informit.com and we will process the deletion of a user's account.


Users can always make an informed choice as to whether they should proceed with certain services offered by InformIT. If you choose to remove yourself from our mailing list(s) simply visit the following page and uncheck any communication you no longer want to receive: www.informit.com/u.aspx.

Sale of Personal Information

Pearson does not rent or sell personal information in exchange for any payment of money.

While Pearson does not sell personal information, as defined in Nevada law, Nevada residents may email a request for no sale of their personal information to NevadaDesignatedRequest@pearson.com.

Supplemental Privacy Statement for California Residents

California residents should read our Supplemental privacy statement for California residents in conjunction with this Privacy Notice. The Supplemental privacy statement for California residents explains Pearson's commitment to comply with California law and applies to personal information of California residents collected in connection with this site and the Services.

Sharing and Disclosure

Pearson may disclose personal information, as follows:

  • As required by law.
  • With the consent of the individual (or their parent, if the individual is a minor)
  • In response to a subpoena, court order or legal process, to the extent permitted or required by law
  • To protect the security and safety of individuals, data, assets and systems, consistent with applicable law
  • In connection the sale, joint venture or other transfer of some or all of its company or assets, subject to the provisions of this Privacy Notice
  • To investigate or address actual or suspected fraud or other illegal activities
  • To exercise its legal rights, including enforcement of the Terms of Use for this site or another contract
  • To affiliated Pearson companies and other companies and organizations who perform work for Pearson and are obligated to protect the privacy of personal information consistent with this Privacy Notice
  • To a school, organization, company or government agency, where Pearson collects or processes the personal information in a school setting or on behalf of such organization, company or government agency.


This web site contains links to other sites. Please be aware that we are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of each and every web site that collects Personal Information. This privacy statement applies solely to information collected by this web site.

Requests and Contact

Please contact us about this Privacy Notice or if you have any requests or questions relating to the privacy of your personal information.

Changes to this Privacy Notice

We may revise this Privacy Notice through an updated posting. We will identify the effective date of the revision in the posting. Often, updates are made to provide greater clarity or to comply with changes in regulatory requirements. If the updates involve material changes to the collection, protection, use or disclosure of Personal Information, Pearson will provide notice of the change through a conspicuous notice on this site or other appropriate way. Continued use of the site after the effective date of a posted revision evidences acceptance. Please contact us if you have questions or concerns about the Privacy Notice or any objection to any revisions.

Last Update: November 17, 2020