diff --git a/builder/build.ps1 b/builder/build.ps1
index dcb2ba4..31ee3a4 100644
--- a/builder/build.ps1
+++ b/builder/build.ps1
@@ -30,6 +30,9 @@ if ($Sign) {
 Write-Output "Building WinBGP service"
 & "..\service\WinBGP-Service.ps1" -Build
 Move-Item -Path "..\builder\WinBGP-Service.exe" -Destination "..\service\WinBGP-Service.exe" -Force
+if ($Sign) {
+    & "C:\Program Files (x86)\Windows Kits\10\bin\10.0.26100.0\x64\signtool.exe" sign /sha1 $CertificateThumbprint /tr http://time.certum.pl/ /td sha256 /fd sha256 /v "..\service\WinBGP-Service.exe"
+}
 
 # Building engine
 Write-Output "Building engine"