AWS Signer vs OpenPubkey

AWS Signer is a managed code-signing service for verifying code integrity and publisher trust. It supports signing AWS Lambda deployment packages, code for supported IoT devices, and OCI container images using Notation. Lambda verifies signatures and package integrity when signed code is deployed. For containers, Signer works with Notation in registries such as Amazon ECR, with signatures stored alongside images for verification.

Administrators control access to Signer resources and actions through AWS Identity and Access Management policies. Signing profiles can be managed in the Signer console, AWS CLI, or API. Signer manages certificates and keys for Lambda and container workflows; IoT workflows can use a code-signing certificate imported into AWS Certificate Manager. Documentation also lists integrations with AWS Certificate Manager and CloudTrail, plus Amazon EKS image verification. Notation CLI and Signer plugin installers are listed for Linux, macOS, and Windows. API actions have per-second quotas by account and Region, with no minimum request rate. Use with specified AWS services has no additional charge, though related charges may apply.

OpenPubkey binds a user or workload identity established through OpenID Connect to a public key, so the identity can sign messages or artifacts. A PK Token represents control of an OIDC identity and its related private key at a particular time, provided the verifier trusts the identity provider. The project lists Google, Azure/Microsoft, Okta, OneLogin and Keycloak as compatible without changes to those providers; however, its client and verifier currently create and verify tokens from Google for users and GitHub for workloads. Current workload identity use requires GQ signatures. For user identity, they are unnecessary when the PK Token is not public. GQ signatures allow the identity provider’s signature to be stripped from an ID Token while preserving proof of that signature, preventing use against OIDC resource providers. OpenPubkey says it needs no additional certificate authority because the OpenID Provider fulfills that role. Public PK Tokens can reveal claims from an OIDC ID Token, potentially including a name or email address. The project is free under the Apache 2.0 license and is a Linux Foundation project; its repository says it is being prepared for version 1.0. The project directs technical questions to GitHub issues and offers a community Slack channel.