Code Signing Certificate: Why It Matters and How It Works
How does a Code Signing certificate work
What is Code Signing?
It’s a digital certificate that developers use to sign software, drivers, and scripts.
Its main purpose is to prove the authenticity of the file and protect it from tampering.
Why use Code Signing?
- User trust: instead of “Unknown Publisher,” users see the verified company name.
- Integrity & security: ensures that the file hasn’t been altered or infected after release.
- System requirements: Windows, macOS, and modern browsers check for digital signatures. For Windows drivers, signing is mandatory.
- Company reputation: signed files are less likely to be flagged by antivirus software.
How does it work?
- A developer requests a certificate from a Certificate Authority (CA), e.g., DigiCert or Sectigo.
- The CA verifies the company or individual.
- The software is signed using tools such as signtool, osslsigncode, or directly within an IDE.
- When launched, the system checks if the certificate is valid and if the file hasn’t been modified.
Types of Code Signing Certificates
- Standard — stored as a PFX file, suitable for most applications.
- EV Code Signing — issued with a secure hardware token (USB key), instantly removes Windows SmartScreen warnings.
Where is it used?
- signing Windows applications (EXE, MSI);
- drivers;
- scripts (PowerShell, Java, Python);
- mobile apps (Android, sometimes iOS).
👉 Conclusion: A Code Signing certificate is like a digital “passport” for your software — boosting trust, ensuring integrity, and meeting security requirements.