sunlight-secretmanager

sunlight-secretmanager is a command-line tool to manage a Sunlight CT Log’s private key material.

All CT logs have a private key which they use to create Signed Certificate Timestamps (SCTs) and Signed Tree Heads (STHs). Sunlight does not take this private key as input directly. Instead, its configuration requires two file paths:

• A seed file containing at least 32 bytes of random data, from which the log’s ECDSA P-256 key will be derived; and
• A PEM file containing the corresponding ECDSA P-256 public key.

The purpose of sunlight-secretmanager is to authenticate to AWS Secrets Manager, retrieve a stored seed, use that seed to derive the corresponding pubkey, and write both files to disk in a tmpfs. It knows what seed to retrieve and where to write the output files by parsing the same config file which configures the Sunlight log itself.

If it successfully retrieves a secret from AWS Secrets Manager but that secret is empty, it will generate a new seed and save it back to AWS before proceeding. This allows for seamless setup of new log shards simply by adding them to Terraform.

Usage

Sign in the AWS SDK so it populates your environment with the appropriate values, and then:

$ sunlight-secretmanager -config /path/to/sunlight/config.yml