diff --git a/os/windows/winstore/generate-key.ps1 b/os/windows/winstore/generate-key.ps1
new file mode 100644
--- /dev/null
+++ b/os/windows/winstore/generate-key.ps1
@@ -0,0 +1,21 @@
+[CmdletBinding()]
+[Alias()]
+Param
+(
+    # Publisher ("CN=xyz")
+    [Parameter(Mandatory=$true, Position=0)]
+    $Publisher,
+
+    # Password
+    [Parameter(Mandatory=$true, Position=1)]
+    $PasswordParam,
+
+    # Filename
+    [Parameter(Mandatory=$true, Position=2)]
+    $OutputFilename
+)
+
+$cert = New-SelfSignedCertificate -Type Custom -Subject $Publisher -KeyUsage DigitalSignature -FriendlyName "OpenTTD signing certificate" -CertStoreLocation "Cert:\CurrentUser\My" -TextExtension @("2.5.29.37={text}1.3.6.1.5.5.7.3.3", "2.5.29.19={text}")
+
+$password = ConvertTo-SecureString -String $PasswordParam -Force -AsPlainText
+Export-PfxCertificate -cert "Cert:\CurrentUser\My\$($cert.Thumbprint)" -FilePath $OutputFilename -Password $password