Microsoft does provide a way to enable SECDRV on 64-bit Windows.

• Install a game that brings (a recent version of) SECDRV.sys.

• Start the game. It should prompt for elevation. Elevate. It won't work, but you have to do it once.
  If there is an error about insufficient permissions, launch the game explicitly as Administrator, either by right-clicking the shortcut and selecting Run as Administrator or by launching the game by typing the executables path and name from an elevated command prompt.
  Dismiss all errors about things not working and quit the game. Also ignore and do not accept any changes suggested by Windows to run the game in compatibility mode or as Administrator or anything else. That might still be required for the game itself, it is not required for SECDRV to work besides running it elevated just once.

• Install the Windows 10 SDK from Get the standalone Windows 10 SDK.
  Just install all components.

• Start PowerShell as an administrator.

• Make sure you are on 64-bit Windows. Going through this guide on 32-bit Windows is pretty pointless - games should work without. SECDRV just works on 32-bit Windows.

  [System.Environment]::Is64BitOperatingSystem
  

• Find makecat.exe, makecert.exe and signtool.exe and add the path to your PATH in System Properties, Environment Variables.
  The ones in a x86 subfolder are always OK on all Intel architecture chips. No need to match the hardware or the OS bitness.

  $SdkToolsPath = dir -Path "${env:ProgramFiles(x86)}\Windows Kits\10" -Recurse -Directory | where { $n = $_.FullName; $_.BaseName -eq "x86" -and [System.IO.File]::Exists("$n\makecert.exe") -and [System.IO.File]::Exists("$n\makecat.exe") -and [System.IO.File]::Exists("$n\signtool.exe") } | sort CreationTime | select -Last 1
  $env:Path = "$env:Path;$($SdkToolsPath.FullName)"
  

• Create a new folder in your Downloads folder

  $WorkingDirectory = "$env:UserProfile\Downloads\SECDRV"
  if (-not (Test-Path $WorkingDirectory)) { mkdir $WorkingDirectory | Out-Null }
  

• Run all further commands in a PowerShell prompt as Administrator in the folder you created.

  cd $WorkingDirectory
  

• Copy SECDRV.sys in it. Match your operating system bitness.
  If it's an old version, replace it with this one downloadable here. Its from September 2006.

  # Using curl (Windows 10 has it inbox)
  curl.exe -OL https://github.com/ericwj/PsSecDrv/raw/master/tools/SECDRV/SECDRV.sys
  # Using PowerShell or PowerShell Core
  iwr -Uri https://github.com/ericwj/PsSecDrv/raw/master/tools/SECDRV/SECDRV.sys -OutFile SECDRV.sys
  

  That one is 64-bit.

• Check that you have the correct bitness:

  $bytes = [System.IO.File]::ReadAllBytes("$PWD\SECDRV.sys")
  [int]$pe = [System.Text.Encoding]::ASCII.GetString($bytes, 0, 1KB).IndexOf("PE`0`0")
  $mc = [System.BitConverter]::ToUInt16($bytes, $pe + 4)
  switch ($mc) { 0x8664 { "64-bit" } 0x014c { "32-bit" } default { "Unknown" } }
  

  This is a very opportunistic way of reading the machine type in about as few lines as possible by simply finding the first occurrence of PE\0\0 in the file. So use with caution.

  The even more opportunistic way is to simply do type SECDRV.sys | more, make sure the first two letters are MZ and look for PE usually all by itself on a line about a screen down of This program cannot be run in DOS mode. and see if you can find L or d two lines down from it.

  1. If the letter is L then the PE file is probably 32-bit (L is 0x4c in ASCII).
  2. If the letter is d then the PE file is probably 64-bit (d is 0x64 in ASCII).
  

• Enable test signing boot mode.

  bcdedit /set "{current}" testsigning on
  

• Pick a subject - any subject, but include the text "SECDRV" in it

  $Subject = "SECDRV.sys Published by \\$env:ComputerName\$env:UserName on $("{0:yyyy-MM-dd HH:mm}" -f [datetimeoffset]::Now)"
  

• Create a root certificate. 

  # try this
  makecert -r -sr LocalMachine -ss My -n $Subject
  # if it doesn't work, use this
  makecert -r -sr LocalMachine -ss My -n "CN=$Subject"
  

• Open Local Machine Certificates.

  certlm.msc
  

• Go to Personal, Certificates and select the certificate created, there usually is only one, or match the subject, right click Copy.

• Go to Trusted Root Certification Authorities, Certificates. Paste.

• Go to Trusted Publishers, Certificates. Paste.

• Make a text file called SECDRV.cdf in the folder and put the text between @" and "@ in it.

  Set-Content -Path SECDRV.cdf -Value @"
  [CatalogHeader]
  Name=SECDRV.cat
  PublicVersion=0x1
  EncodingType=0x00010001
  CATATTR1=0x10010001:OSAttr:2:6.0
  [CatalogFiles]
  <hash>SECDRV=SECDRV.sys
  "@
  

• Make a driver catalog file in the folder.

  makecat -o SECDRV.txt -r SECDRV.cdf
  

• Get the thumbprint of the certificate you created. The thumbprint is shown in certlm for the certificate created, just double click it and look around, without spaces. Or get it in PowerShell with dir:

  $Publishers = dir Cert:\LocalMachine\TrustedPublisher | where HasPrivateKey | sort NotAfter
  $Publishers | select Thumbprint, NotBefore, NotAfter, Subject
  $Publisher = $Publishers | select -Last 1

• Sign the driver.

  signtool sign /sm /s TrustedPublisher /sha1 "$($Publisher.Thumbprint)" /t https://timestamp.digicert.com secdrv.cat
  

  If you get SignTool Error: No file digest algorithm specified. (...) use the /fd certHash option., run this instead

  signtool sign /sm /s TrustedPublisher /sha1 "$($Publisher.Thumbprint)" /fd SHA256 /t https://timestamp.digicert.com secdrv.cat
  

• Install the driver. This adds it to the driver catalog on your system, but does not copy files or create driver services.

  signtool catdb /u secdrv.cat
  

• Just to be sure, overwrite the SECDRV.sys referred to by the kernel driver service with the exact version that you signed and installed.

  sc.exe qc secdrv
  

  If the output has something like \??\C:\Windows\system32\drivers\SECDRV.sys, copy that path excluding \??\ and use it in the next command:

  copy .\SECDRV.sys "C:\Windows\system32\drivers\SECDRV.sys"
  

• Reboot.

• Test if it works.

  sc.exe start secdrv
  

If it doesn't work, check these reasons.

• You are not an Administrator or you opened the PowerShell prompt without elevation. Right click the button in the Task Bar and hit Run as Administrator and start over.
• SECDRV.sys is too old. Then the driver doesn't start. Right click it, hit Properties, go to Details and check Product version. It contains a date as a string. If you downloaded it from the link above, the version is "SECURITY Driver 4.03.086 2006/09/13".
• SECDRV.sys is 32-bit and your Windows is 64-bit. Download SECDRV.sys from the link given.
• SECDRV.sys is 64-bit and your Windows is 32-bit. Then don't download the driver from the link given, but use whichever version came with the game you installed. Also you shouldn't have started following this guide in the first place.
• You might have to run games that need SECDRV as Administrator. The driver might not be installed and the driver services might not be present until you have tried this.
• Secure Boot is enabled. Run bcdedit again after disabling it.
• You didn't reboot. You will have to reboot.

Now play games.