I'm putting together a retro Windows NT 4.0 setup and am trying to locate the SP6a high-encryption 128-bit package for Intel x86 systems. I initially searched for a file named SP6128I.EXE, but only the standard SP6 package, SP6386i.exe, seems to be readily available. Does anyone know the correct filename or where this high-encryption release can be found?
1 Answer
The filename may be different from SP6128I.EXE. The relevant package appears to be SP6A386.EXE or a similarly named x86 SP6a installer. You can verify it by checking whether the extracted files include rsaenh.dll as well as rsabase.dll—the presence of rsaenh.dll indicates the 128-bit high-encryption components are included.

That clears it up. SP6A386.EXE does appear to be the high-encryption version: unlike the basic 40/56-bit packages, it includes rsaenh.dll in addition to rsabase.dll. Thanks!