Every time a user installs software, their operating system must decide whether to trust it. Code signing certificates are the mechanism that bridges that trust gap, proving the publisher's identity and guaranteeing the code has not been tampered with since it was signed.
Software supply chain attacks have become one of the most damaging categories of cybersecurity incidents. When attackers compromise a build pipeline or inject malicious code into a legitimate application, the impact cascades to every user who downloads and runs the tampered software. High-profile incidents, from the SolarWinds breach to compromised npm packages, have shown that trusting software by default is no longer viable.
Code signing addresses this problem at its root. By attaching a cryptographic signature to an executable, library, driver, or script, the developer creates a verifiable proof that the code comes from a known source and has not been modified since it was published. Operating systems, browsers, and enterprise security tools use these signatures to make trust decisions: signed code from a recognized publisher runs smoothly, while unsigned or tampered code triggers warnings or is blocked outright.
A code signing certificate is the digital certificate that makes this possible. Issued by a trusted Certificate Authority, it binds the publisher's identity to a public key and is used by signing tools to produce signatures that operating systems can verify.
The signing tool computes a cryptographic hash (typically SHA-256) of the binary, script, or package. This hash is a unique fingerprint: even a single-byte change in the code will produce a completely different hash value.
The hash is encrypted with the developer's private key, producing the digital signature. The signature, along with the code signing certificate (which contains the public key and the publisher's verified identity), is embedded into the file or attached alongside it.
When the user downloads or runs the software, the operating system extracts the signature and uses the publisher's public key to decrypt the hash. It then independently hashes the downloaded file. If the two hashes match and the certificate chains back to a trusted CA, the software is verified as authentic and untampered.
Centralized certificate inventory — Evertrust CLM discovers and tracks every code signing certificate across your organization, regardless of which CA issued it or where the key is stored, giving you a single pane of glass over your entire signing infrastructure.
Policy enforcement — Define and enforce organizational rules on which teams can request code signing certificates, what key algorithms and storage mechanisms are allowed, and which approval workflows must be followed before a certificate is issued.
Automated lifecycle — Evertrust PKI automates the issuance and renewal of code signing certificates, integrating with your CI/CD pipelines to ensure signing certificates are always current and compliant, eliminating the risk of expired signatures in production.
Audit & compliance — Full audit trails of every certificate request, approval, issuance, and signing operation, helping your organization demonstrate compliance with internal security policies and external regulatory requirements.
