Adding time stamps for integrity to generator security constraints with an XPath expression

 

Before you begin

Prior to completing this task, import your application into an assembly tool. For information on how to import your application, see Import enterprise applications.

The following information explains the difference between using an XPath expression and using keywords to specify which part of the message to sign:

XPath expression

Specify any part of the message using an XPath expression. XPath is a language that is used to address parts of an XML document. We can find information on XPath syntax at the following Web site: http://www.w3.org/TR/1999/REC-xpath-19991116.

Keywords

Specify only elements within the message using predefined keywords.

 

Overview

This task is used to specify that a time stamp is embedded in a particular element and that the element is signed. Complete the following steps to specify the time stamp for integrity using keywords when you configure the generator security constraints for either the request generator or the response generator. The request generator is configured for the client and the response generator is configured for the server. In the following steps, configure either the client-side extensions in step 2 or the server-side extensions in step 3.

 

Procedure

1. Start the assembly tool and click Window > Open Perspective > J2EE.

2. Optional: Locate the client-side extensions using the Project Explorer window. The Client Deployment Descriptor window is displayed. This Web service contains the extensions that we need to configure. Complete the following steps to locate the client-side extensions.

   1. Expand the Web Services > Client section and double-click the name of the Web service.

   2. Click the WS Extension tab and expand the Request Generator Configuration section.

3. Optional: Locate the server-side extensions using the Project Explorer window. The Web Services Editor window is displayed. This Web service contains the extensions that we need to configure. Complete the following steps to locate the server-side extensions.

   1. Expand the Web Services > Services section and double-click the name of the Web service.

   2. Click the Extensions tab and expand the Response Generator Service Configuration Details section.

4. Expand the Integrity section. Integrity refers to digital signature while confidentiality refers to encryption. Integrity decreases the risk of data modification when you transmit data across a network. For more information on digitally signing SOAP messages, see XML digital signature.

5. Click Add to specify a time stamp for integrity. The Integrity Dialog window is displayed. Complete the following steps to specify a configuration:

   1. Specify a name for the integrity element in the Integrity Name field. For example, you might specify int_tmstmp.

   2. Specify an order in the Order field. The value, which must be a positive integer value, specifies the order in which the digital signature is processed. An order value of 1 specifies that the signing is done first.

6. Click Add in the Timestamp section of the Integrity Dialog window. Complete the following steps to specify a time stamp configuration:

   1. Select the Timestamp dialect from the Timestamp section. The http://www.w3.org/TR/1999/REC-xpath-19991116 dialect specifies the message part to which the time stamp is added and signed using the XPath expression.

   2. Select the message part in the Timestamp keyword field to which the time stamp is added and signed using an XPath expression. For example, to specify that the time stamp is added to the body and is signed, you might specify the following expression for the Timestamp keyword

      /*[namespace-uri()='http://schemas.xmlsoap.org/soap/envelope/' 
      and local-name()='Envelope']/*[namespace-uri()='http://schemas.
      xmlsoap.org/soap/envelope/' and local-name()='Body']
      

   3. Specify an expiration time for the time stamp in the Timestamp expires field. The time stamp helps defend against replay attacks. The lexical representation for the duration is the [ISO 8601] extended format PnYnMnDTnHnMnS, where:

      P

      Precedes the date and time values.

      nY

      Represents the number of years in which the time stamp is in effect. Select a value from 0 to 99 years.

      nM

      Represents the number of months in which the time stamp is in effect. Select a value from 0 to 11 months.

      nD

      Represents the number of days in which the time stamp is in effect. Select a value from 0 to 30 days.

      T

      Separates the date and time values.

      nH

      Represents the number of hours in which the time stamp is in effect. Select a value from 0 to 23 hours.

      nM

      Represents the number of minutes in which the time stamp is in effect. Select a value from 0 to 59 minutes.

      nS

      Represents the number of seconds in which the time stamp is in effect. The number of seconds can include decimal digits to arbitrary precision. You can select a value from 0 to 59 for the seconds and from 0 to 9 for tenths of a second.

      For example, to indicate 1 year, 2 months, 3 days, 10 hours, and 30 minutes, the format is P1Y2M3DT10H30M. Typically, you might configure a message time stamp for between 10 and 30 minutes. For example, 10 minutes is represented as P0Y0M0DT0H10M0S or PT10M.

7. In the Message Parts section, click Add and select http://www.ibm.com/websphere/webservices/wssecurity/dialect-was in the Message parts dialect field.

8. In the Message Parts section, select the message parts keyword. Important: You must define at least one message part in the Message Parts section in order to specify a time stamp for integrity. This message part is signed as well as the parent element of the time stamp.

9. Click OK to save the configuration changes.

   Note: These configurations for the generator and the consumer must match.

   In addition to the time stamp, one can specify that the nonce is signed. For more information, see the following articles:

   • Adding a nonce for integrity in generator security constraints with keywords

   • Adding a nonce for integrity to generator security constraints with an XPath expression

 

What to do next

After you have specified which message parts to digitally sign, you must specify which method is used to digitally sign the message. For more information, see Configuring signing information for the generator binding with an assembly tool.

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Related Tasks

Adding a stand-alone time stamp to generator security constraints
Adding a nonce for integrity to generator security constraints with an XPath expression
Configuring signing information for the generator binding with an assembly tool
Adding a nonce for integrity in generator security constraints with keywords

 

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