c# validate gtin Lesson Review in Visual C#.NET

Printer GTIN - 13 in Visual C#.NET Lesson Review

You can use the following questions to test your knowledge of the information in Les son 2, Using soapExtensionTypes. The questions are also available on the companion CD if you prefer to review them in electronic form.

Answers to these questions and explanations of why each answer choice is right or wrong are located in the Answers section at the end of the book.

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1. Which soapExtensionTypes tasks can be done with a configuration file (Select all that apply.) A. soapExtensionTypes can be added to the project. B. soapExtensionTypes can be removed from the project. C. All soapExtensionTypes that have been added can be cleared at once. D. soapExtensionTypes cannot be managed through a configuration file. 2. Which is true with respect to soapExtensionTypes declarations in a configuration file (Select the best answer.) A. A priority value of 2 takes higher precedence than a priority value of 1. B. A group value of 1 takes higher precedence than a group value of 0. C. A priority value of 1 takes higher precedence than a priority value of 2. D. Numeric values do not control priority in either the priority or the group tags. 3. What modifications are necessary to use a specific configuration section (Select all that apply.) A. Add an entry to the <configSections> section of the configuration file. B. The assembly name, the assembly version, and the default culture can all be specified in the custom configuration section. C. An entry matching the name specified in the <configSections> entry must be included outside of this section. D. An element with the name of the assembly must be included in the config uration file. A configSection attribute should be added to this element.

One of the biggest selling points of Web Services Enhancements and Web Services Enhancements 3.0 in particular is the enhanced security features. Like the early WSE counterparts, WSE 3.0 implements the WS-Security 1.1 specification.

General information about the WS-Security specification can be found at the following Uniform Resource Locator (URL): http://en.wikipedia.org/wiki/WS-Security.

The WS-Security 1.1 specification seeks to address three primary objectives with respect to messages:

Ensure that the message was not tampered with during the transmis sion from sender to receiver. Verify the identity of both the sender and receiver of the mes

After this lesson, you will be able to:

Until recently, written human signatures were the main way in which contractual agreements were executed. By signing a contract, I verify that I read it and that I accept the terms of the contract. If I sign a check, I acknowledge that I in fact want to engage in the transaction and that I thereby authorize it. However, there have always been dis honest people who have been able to benefit by forging signatures. As such, most institutions such as banks have signature cards on file so that they can compare a sig nature they know is authentic with any incoming checks. This system, however, as is the case with all handwriting verifications, involves a human being checking a new signature against a signature card to determine whether the signature is authentic. In

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a bank, most employees are qualified to make this determination for the bank, but in larger transactions or disputes, handwriting experts are brought in to verify signature authenticity. Signature verification is always more art than science and, because the costs of being wrong can be very high, it is potentially problematic. Now that electronic commerce has become commonplace, signature verification is not feasible in many cases. Imagine that you need $20 to eat dinner or to purchase gas oline. If a human was necessary to verify your signature, the bank would be required to be open 24 hours a day to provide this service. Instead, most of us now use auto mated teller machine (ATM) cards. Each card has a personal identification number (PIN) that, if kept private, helps ensure that only the intended user can withdraw money from a given account. An ATM card corresponds to my account specifically. Short of a really sophisticated forgery mechanism, I can only use my ATM card to withdraw money from my account. If someone gets possession of my card but doesn t have my PIN, he or she won t be able to withdraw money from my account unless he or she can somehow procure my PIN. Digital signatures work much the same way. When a message is digitally signed, a user name and password are usually required to create the signature. This requirement ensures that senders are who they say they are. The message itself is used to create a hash value that mathematically can correspond only to this particular message (even a small change results in a different hash value) or a very small subset of possible messages. When the message is received, the hash can be verified and if it matches the one generated when the message was signed, it s safe to assume that the message wasn t tampered with. Although digital signatures aren t 100 percent guaranteed to be authentic, the chances of tampering are so small that a digital signature s security far exceeds the security of traditional methods such as handwriting. For SOAP messages, there are four mechanisms that can be used to digitally sign mes sages:

A UserNameToken object containing a user name and password combination. A digital certificate such as X.509. A Kerberos token. Kerberos is powerful but limited in use because it can only be issued and verified on a machine running Microsoft Windows XP Service Pack 1 or later or Microsoft Windows Server 2003.