diff --git a/windows/cygwin.ps1 b/windows/cygwin.ps1
index 21c1f965..e107de45 100755
--- a/windows/cygwin.ps1
+++ b/windows/cygwin.ps1
@@ -53,12 +53,12 @@ try {
 	Write-Host "Listing keys in ${PSScriptRoot}\cygwin.gpg"
 	Get-ChildItem -Force "${PSScriptRoot}\cygwin.gpg"
 	& $GPG --debug-all --no-default-keyring `
-	    --keyring ${PSScriptRoot}\cygwin.gpg `
+	    --keyring "${PSScriptRoot}\cygwin.gpg" `
 	    --list-keys
 	Write-Host "... ok?"
 	& $GPG --quiet --no-default-keyring `
-	    --keyring ${PSScriptRoot}\cygwin.gpg `
-	    --verify ${Cygwin}\${Setup}.sig ${Cygwin}\${Setup}
+	    --keyring "${PSScriptRoot}\cygwin.gpg" `
+	    --verify "${Cygwin}\${Setup}.sig" "${Cygwin}\${Setup}"
 	if ($LastExitCode -ne 0) {
 		throw "GPG signature verification failed"
 	}