The random number generator is not compliant with Federal Processing Standard 140-2 in Windows Vista Service Pack 1 and in Windows Server 2008

In Windows Vista Service Pack 1 (SP1) and in Windows Server 2008, the random number generator (RNG) is not compliant with Federal Information Processing Standard (FIPS) 140-2.

This problem affects all the functions that use the RNG. The CryptoAPI function CryptGenRandom and the CNG function BCryptGenRandom use the RNG directly. Other functions that generate random numbers for keying material or for other purposes may also use the RNG indirectly.

Important This problem does not affect the external behavior of any functions that use the RNG. It does not affect the strength of any system cryptographic implementations. Additionally, it does not change cryptographic functionality in any other way.

This problem occurs because certain internal self-tests are missing from the RNG.

A hotfix is available to resolve this problem. This hotfix contains changes to the cryptographic libraries in Windows Vista SP1 and in Windows Server 2008. These changes make the RNG fully compliant with the requirements of FIPS 140-2.

Note This hotfix does not change the functionality of the RNG.

After you install this hotfix, all cryptographic binaries that are affected will be updated with versions that contain the required self-tests.

Hotfix information

A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing this specific problem. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix.

If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, contact Microsoft Customer Service and Support to obtain the hotfix.

Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft Web site: Note The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.

Important Windows Vista and Windows Server 2008 hotfixes are included in the same packages. However, only one of these products may be listed on the �Hotfix Request� page. To request the hotfix package that applies to both Windows Vista and Windows Server 2008, just select the product that is listed on the page.

Prerequisites

The following list contains prerequisites for the hotfix:

• Windows Vista SP 1 or Windows Server 2008

Restart requirement

You have to restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix replaces the following hotfix:

Registry information

To use one of the hotfixes in this package, you do not have to make any changes to the registry.

File information

The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time item in Control Panel.

Windows Vista SP1 and Windows Server 2008, x86-based versions

Windows Vista SP1 and Windows Server 2008, x64-based versions

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

For more information about FIPS 140 evaluation, visit the following Microsoft Web site:For more information about the BCryptGenRandom function, visit the following Microsoft Web site:For more information about the CryptGenRandom function, visit the following Microsoft Web site:For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base: