Differences Between 128-bit and 40-bit versions of Service Pack 3 and Service Pack 4

MORE INFORMATION

Because of US government regulations that restrict the export of software containing strong (128-bit) cryptographic algorithms, Microsoft produces two versions of the North American English service packs. One which implements strong cryptographic algorithms (128-bit) and is not exportable outside North America without an export license, and a second version that contains exportable (40-bit) cryptographic code, which is exportable to most destinations without restriction.

Because of these governmental export restrictions, no localized versions of Windows NT are currently available in 128-bit versions. Non-North American English versions of these files contain only exportable cryptographic code.

In Service Pack 3, the only files that are different between the 40-bit and 128-bit versions of the service packs are:

• Ndiswan.sys
• Ntlmssps.dll
• Schannel.dll
• Security.dll
• Update.inf

Additionally, the 128-bit version also includes Rsaenh.dll.

Perform the following steps to verify the version of the files installed:

1. Start Windows NT Explorer.
2. Right-click the file, click Properties, and then click the Version tab.
3. Note the description.
   
   40-bit:
   

         File Name     Description
         -------------------------
         Ndiswan.sys   MS WAN Wrapper Network Driver (Export Version)
         Ntlmssps.dll  NtLm Security Support Provider Service DLL (Export
                       Version)
         Schannel.dll  PCT / SSL Security Provider (Export Version)
         Security.dll  NtLm Security Support Provider Client DLL (Export
                       Version)
   						

   
   128-bit:
   

         File Name     Description
         -------------------------
         Ndiswan.sys   MS WAN Wrapper Network Driver (Domestic Use Only)
         Ntlmssps.dll  NtLm Security Support Provider Service DLL (Domestic
                       Use Only)
         Rsaenh.dll    Microsoft Enhanced Cryptographic Provider (US/Canada
                       Only, Not for Export)
         Schannel.dll  PCT / SSL Security Provider (US and Canada Use Only)
         Security.dll  NtLm Security Support Provider Client DLL (Domestic
                       Use Only)
   						

Installing 40-bit Service Pack on a 128-bit Windows NT installation will possibly result in reduced functionality.

Installing 128-bit Service Pack on a 40-bit Windows NT installation will replace all the files concerning encryption and will make the installation 128bit.

NOTE: The uninstall procedure for Service Pack 4 will retain the 128-bit schannel.dll but returns all other encryption files to 40-bit versions.

When installing hotfixes that replace any one of these files, you should be sure to install the correct version of the hotfix to maintain the correct cryptographic strength.