Helper Assembly to copy text to the Windows clipboard without adding it to the history.
In PowerShell I often copy text into the Windows clipboard. Sometimes the information is sensitive and I clear the clipboard straight after use.
With version 1809 of Windows 10, Microsoft introduced two new features to the Windows clipboard.
- Clipboard History - to keep multiple entries of the clipboard content around.
- Cloud Sync - to sync your clipboard content to your Microsoft account, so you can access it from other devices.
Both these new features sound cool, but I certainly don't want to use them with my sensitive data.
PowerShell has the Set-Clipboard cmdlet to copy a text to the clipboard,
but if the user has enabled the clipboard history there is no way in your
PowerShell script to prevent your data ending up in the history.
For this reason I had to keep the clipboard history turned off.
The solution I came up with is a small .Net Framework assembly that can access new APIs in Windows 10 to copy text to the clipboard without adding it to the history.
The Assembly targets .Net Framework Vs.4.8, I guess 4.6 and 4.7 should work as well.
Also you need to have Windows 10 version 1903 or newer.
Just build the project in Visual Studio and copy the resulting DLL to a well-known location on your device.
You can also download the DLL using the releases link on Github.
Now to copy text to the clipboard without adding it to the history use:
[Reflection.Assembly]::LoadFile("C:\stuff\Hacon.ClipboardHelper.dll") | Out-Null
[Hacon.ClipboardHelper.Windows10Clipboard]::Copy("my sensitive data")
The copy method has an overload which allows you to be more specific:
[Hacon.ClipboardHelper.Windows10Clipboard]::Copy("my sensitive data",$true,$false)
This allows the history but prevents using the cloud sync.
The basic Copy method has both parameters set to $false.
It turns out you can do the same thing in PowerShell itself. The file PurePowerShell.ps1 has a function Set-ClipboardWithoutHistory which allows you to copy a string to the Windows Clipboard without history or cloud.
see also issue #1