To 128 bits at least!
Encryption Pack Installation May Not Work If User GUID Is Too Long
After you install the Windows 2000 High Encryption Pack and it appears to
succeed, any program that relies on 128-bit security (such as Microsoft
Internet Explorer) may still report 56-bit security in use rather than
128-bit after you reboot the computer.
http://support.microsoft.com/?kbid=253540 (W2000 Oct. 16, 2002)
Problems with 128-Bit Encryption Pack After Uninstalling Service Pack 1
If you uninstall Windows 2000 Service Pack 1 (SP1) from a computer that has
Windows 2000 High Encryption Pack (128-bit) installed, the encryption may be
reduced to 56-bit.
http://support.microsoft.com/?kbid=269675 (W2000 May 28, 2003)
