This update adds support for the following Advanced Encryption Standard (AES) cipher suites in the Schannel.dll module for Windows Server 2003:

•	TLS_RSA_WITH_AES_128_CBC_SHA AES128-SHA
•	TLS_RSA_WITH_AES_256_CBC_SHA AES256-SHA

Note These cipher suites are based on the RC4 algorithm.

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OpenSSL supports several 128-bit and 256 bit AES cipher suites. OpenSSL is used in most open software products in Unix systems. For example, OpenSSL is used in Sendmail, Postfix, Firefox, and Thunderbird. Currently, the only 128-bit cipher suite that is mutually available is RC4. Additionally, there is no 256-bit cipher available.

If customers set the high cipher strength option in OpenSSL for their software product, OpenSSL disables all 128-bit ciphers. In this case, Windows systems cannot negotiate by using Transport Layer Security (TLS) because there are no mutually supported cipher suites. Therefore, there is usually an interoperability issue between Microsoft Exchange Server and the Postfix server or there is an interoperability issue between Microsoft Exchange Server and the Sendmail server. The only workaround is to use a weaker cipher and a weaker cipher strength.

With this update, you can support 128-bit and 256-bit cipher suites without Cryptography Next Generation (CNG). This update enables you to use a higher cipher strength. This update also fixes the interoperability issue between the Exchange server and the Sendmail server. This update also fixes the interoperability issue between the Exchange server and the Postfix server.

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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.

Prerequisites

To apply this hotfix, you must have Windows Server 2003 Service Pack 2 (SP2) installed on the computer.

Restart requirement

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

Hotfix replacement information

This hotfix does not replace any other previously released hotfixes.

Registry information

To use this hotfix, 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 Server 2003 SP2, x86-based versions

File name	File version	File size	Date	Time	Platform	SP requirement
Rsaenh.dll	5.2.3790.4313	213,200	13-Jun-2008	15:43	x86	SP2
Schannel.dll	5.2.3790.4313	147,968	13-Jun-2008	15:21	x86	SP2

Windows Server 2003 SP2, x64-based versions

File name	File version	File size	Date	Time	Platform	SP requirement	Service branch
Rsaenh.dll	5.2.3790.4313	305,872	13-Jun-2008	13:30	x64	SP2	Not Applicable
Schannel.dll	5.2.3790.4313	255,488	13-Jun-2008	13:30	x64	SP2	Not Applicable
Wrsaenh.dll	5.2.3790.4313	213,200	13-Jun-2008	13:30	x86	SP2	WOW
Wschannel.dll	5.2.3790.4313	147,968	13-Jun-2008	13:30	x86	SP2	WOW

Windows Server 2003 SP2, Itanium-based versions

File name	File version	File size	Date	Time	Platform	SP requirement	Service branch
Rsaenh.dll	5.2.3790.4313	498,384	13-Jun-2008	13:22	IA-64	SP2	Not Applicable
Schannel.dll	5.2.3790.4313	467,456	13-Jun-2008	13:22	IA-64	SP2	Not Applicable
Wrsaenh.dll	5.2.3790.4313	213,200	13-Jun-2008	13:22	x86	SP2	WOW
Wschannel.dll	5.2.3790.4313	147,968	13-Jun-2008	13:22	x86	SP2	WOW

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For more information, click the following article number to view the article in the Microsoft Knowledge Base:

The third-party products that this article discusses are manufactured by companies that are independent of Microsoft. Microsoft makes no warranty, implied or otherwise, about the performance or reliability of these products.

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