What Is a Code Signing Certificate? How Does It Secure Your Software?
· Software Security
A Code Signing certificate lets developers digitally sign applications, drivers, updates, and scripts. It gives end users two critical assurances: the code came from the authorized developer and hasn't been tampered with since signing.
How It Works
1. Developer obtains a Code Signing certificate from a CA. 2. Signing tool (signtool.exe, codesign) computes a hash of the software. 3. The hash is encrypted with the developer's private key and attached as a signature. 4. When the user runs the software, the OS recomputes the hash and verifies the signature — a match means trusted; a mismatch triggers a warning.
Windows SmartScreen
Unsigned or low-reputation software triggers "Windows protected your PC — the publisher is unknown." EV Code Signing certificates bypass SmartScreen almost entirely because EV certs immediately earn trust reputation.
macOS Gatekeeper
Apple requires software distributed outside the App Store to be signed with a Developer ID certificate and pass Apple notarization. Unsigned, non-notarized apps won't run on default macOS settings.
OV vs EV Code Signing
OV: Organizational validation. SmartScreen may still warn initially; reputation builds with download volume. EV: Highest validation, stored on HSM. Instant SmartScreen trust — even new software runs without warnings. Required for kernel-mode Windows drivers.
What Should Be Signed?
Windows installers (.exe, .msi), drivers, macOS apps and packages, PowerShell scripts, and software updates/patches.
Visit the PekiSSL product page to find the right certificate for your needs.