Windows - Fix private SSH key file permissions, ownership and inheritance

Set-PrivateKeyPermissions.ps1

function Set-PrivateKeyPermissions {
    param (
        [string]$KeyLocation
    )
	if (-not ([Security.Principal.WindowsPrincipal][Security.Principal.WindowsIdentity]::GetCurrent()).IsInRole([Security.Principal.WindowsBuiltInRole]::Administrator)) {
		Write-Error "Must run as administrator. Exiting..."
		Return
	}
	$acl = Get-Acl "$KeyLocation"
	$currentUser = New-Object System.Security.Principal.Ntaccount($acl.owner)
	$accessRule = New-Object System.Security.AccessControl.FileSystemAccessRule($acl.owner,"FullControl","Allow")
	$acl.Access | %{$acl.RemoveAccessRule($_)}
	$acl.SetOwner($currentUser)
	$acl.SetAccessRuleProtection($true,$false)
	$acl.SetAccessRule($accessRule)
	$acl | Set-Acl "$KeyLocation"
}

# Example usage:
Set-PrivateKeyPermissions -KeyLocation 'C:\Keys\thereisnotime.pem'