PRB: CryptoAPI function Error "Error 0x80090006: Invalid Signature" Connecting to SQL Server by Using SQL Server Authentication

When you use SQL Server Authentication to connect to SQL Server, you may receive the following error message:Additionally, in the About Internet Explorer dialog box, there is no Cipher Strength value or the value is 0-bit.

Note To view the Cipher Strength value, in Microsoft Internet Explorer, click About Internet Explorer on the Help menu.

This behavior may occur if any of the following files are missing, damaged, or the incorrect version:

• Ndiswan.sys
• Ntlmssps.dll
• Schannel.dll
• Security.dll
• Rsabase.dll
• Rsaenh.dll

The incorrect versions may exist when you install both 128-bit encryption and 40-bit encryption on the operating system.

To work around this problem, reinstall Microsoft Internet Explorer to have the same version of the security and encryption DLLs.

To authenticate SQL Server login, SQL Server uses the Microsoft Windows NT CryptoAPI functions. When a SQL Server login is created, the password is encrypted with the CryptoAPI functions. The encrypted password is stored in the SQL Server system table. When you use SQL Authentication to connect to SQL Server, the password in the connection string is encrypted and compared with the password that is stored in the system table. The connection is permitted only when both passwords match.

For additional information about Internet Explorer High Encryption Pack, visit the following Microsoft Web site:

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