In the era of cloud-native solutions, ensuring the security of the software supply chain has become a critical priority. As organizations increasingly rely on containerized applications and microservices, the risk of supply chain attacks—such as tampered dependencies or malicious artifacts—has surged. The Notary Project, an initiative under the Cloud Native Computing Foundation (CNCF), addresses these challenges by providing a robust framework for verifying the authenticity and integrity of software artifacts throughout their lifecycle. This article explores the Notary Project’s architecture, key features, and its role in fortifying cloud-native security.
The Notary Project is designed to secure the software supply chain by addressing two primary goals: authentication (ensuring artifacts originate from trusted sources) and integrity (verifying that artifacts remain unaltered from creation to deployment). It achieves this through standardized tools and protocols that align with industry standards such as the Open Container Initiative (OCI) and IETF specifications.
At its core, Notary supports OCI artifacts, which are standardized formats for container images and other cloud-native resources. By leveraging JSON Web Signature (JWT) and COSE (Constrained OAuth Signature) formats, Notary ensures compatibility across diverse environments, including edge devices and IoT systems. Additionally, it integrates time-stamping and revocation checks to validate the validity of signatures over time, supported by third-party security audits.
Notary’s functionality is structured around three critical phases of the software supply chain:
Acquisition Phase: Verifies external images or artifacts by checking their digital signatures, ensuring they originate from trusted sources. Internal repositories also benefit from periodic scanning and signing to maintain compliance.
Construction Phase: Validates base images and tools used in building applications, ensuring they meet organizational policies. Post-construction, Notary signs metadata such as compliance reports and vulnerability assessments.
Deployment Phase: Conducts pre-deployment signature and metadata checks to confirm trustworthiness. It supports multi-level signing (e.g., development, testing, production environments) with environment-specific Certificate Authorities (CAs) to enforce strict validation.
Notary’s modular design allows integration with diverse signing mechanisms, including HSM devices, AWS Signer, Alibaba Cloud, and HashiCorp Vault. Its plugin framework supports customization via TGZ files, enabling developers to use Golang, Python, or other languages. Key commands include key add, generate signature, and get plugin metadata, offering flexibility in signing workflows.
Notary introduces a three-tier signing model:
Trust policies are configured with trust stores and trust identities, allowing organizations to define custom rules based on artifact metadata, such as publisher fields in attestations.
The Notary Project provides a critical layer of security for cloud-native software supply chains by ensuring artifact authenticity and integrity through standardized signing, verification, and trust policies. Its extensibility, alignment with OCI and IETF standards, and support for multi-level validation make it a vital tool for organizations adopting cloud-native solutions. By integrating Notary into DevOps workflows and leveraging its plugin framework, teams can significantly mitigate supply chain risks while maintaining compliance and operational efficiency.