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Container signing using GitHub Actions

DigiCert container signing enables teams to sign container images directly within GitHub Actions workflows. This action integrates Software Trust with CoSign, providing a secure, automated, and scalable solution for validating container integrity before deployment.

This action handles the setup of the DigiCert​​®​​ container signer tool, manages PKCS#11 configuration automatically, performs key and certificate handling, and supports both single-architecture and multi-architecture image signing. Optional signature verification and healthchecks help ensure reliable, end-to-end signing workflows.

To learn more and get started, review our documentation in GitHub.

Features

Centralized, secure signing

  • Uses Software Trust for authenticated, certificate-based signing

  • Automatically extracts the PKCS#11 module path and handles secure client certificate creation

Streamlined CI/CD Integration

  • Runs fully inside GitHub Actions using the DigiCert​​®​​ container signer image

  • Supports signing for private or public registries with optional authentication

Flexible image support

  • Works with both single-architecture and multi-architecture images

  • Offers optional recursive signing and signature verification for enhanced trust

Built-in reliability

  • Includes Software Trust connectivity checks, version checks for CoSign and SMCTL, and comprehensive error handling

  • Provides verbose logging options for easier debugging