Rationale

Sops is the tool we use for managing most of our organizational secrets like passwords, access keys, PII, among others. It allows us to version encrypted files within our Git repositories in a stateless approach.

The main reasons why we chose it over other alternatives are:

1. It is open-source.
   
2. it is Serverless, meaning that it does not require maintaining servers, firewalls, load balancers, or any other typical infrastructure required for common Secrets Engines.
   
3. It supports AWS KMS, which allows to encrypt files using symmetric AES256 keys that only exist within the KMS boundaries, granting almost-impossible key leakage. Access to such keys can be easily managed with a user-level granularity by using AWS IAM.
   
4. It is free. Only costs for decrypting secret files using AWS KMS are incurred.
   
5. As secrets are written as code, it allows software versioning, as encrypted secret files can be securely pushed to git repositories.
   
6. It allows reproducibility and auditability as secrets are versioned.
   
7. It is DevOps friendly, as secret management is now done through Merge Requests, allowing to run CI/CD integrations on the secrets.
   
8. Although secret's KMS keys are very easy to rotate, Sops does not support secret-specific automatic rotations.
   
9. It integrates with other services like PGP, Age, GCP KMS, Azure Key Vault, and Hashicorp Vault.
   
10. It supports Yaml, Json, Env, Ini and Binary formats.
    

Alternatives

The following alternatives were considered but not chosen.

AWS Secrets Manager

1. AWS Secrets Manager is not open-source.
   
2. It is SaaS, meaning that infrastructure complexity is handled by them.
   
3. It supports its own key management system, AWS KMS.
   
4. It charges based on secrets.
   
5. It is a common Secrets Engine, meaning that secrets are not stored as code, losing git versioning. It supports its own versioning.
   
6. It should support auditability and reproducibility as it has its own versioning.
   
7. It is a service that must be managed separately, making integration with DevOps flows harder.
   
8. It supports automatic rotation for some services that are not relevant to us.
   
9. It does not integrate with any other services.
   
10. It does not support any text format, but instead is configurable via GUI.
    

HashiCorp Vault

Infiscal

1. Infiscal is open-source.
2. It is SaaS, meaning that infrastructure complexity is handled by them.
   
3. It supports external key management systems like AWS KMS and GCP KMS.
   
4. It is pretty expensive as it charges based on identities, which are machines or humans that talk to it. It does not scale well with horizontal systems like ours.
   
5. It is a common Secrets Engine, meaning that secrets are not stored as code, losing git versioning. It supports its own versioning.
   
6. It should support auditability and reproducibility as it has its own versioning.
   
7. It is a service that must be managed separately, making integration with DevOps flows harder.
8. It supports automatic rotation for some services that are not relevant to us.
9. It integrates with Slack.
   
10. It does not support any text format, but instead is configurable via GUI.
    

Torus

1. Torus was used a few years ago but it got discontinued. One year later they relaunched their service. It is not open-source.
   
2. It is SaaS, meaning that infrastructure complexity is handled by them.
   
3. It does not support any external key management service.
   
4. It does not publish its prices.
   
5. It is a common Secrets Engine, meaning that secrets are not stored as code, losing versioning.
   
6. It does not support auditability and reproducibility as there is no versioning.
   
7. It is a service that must be managed separately, making integration with DevOps flows harder.
8. It does not seem to support automatic rotations.
   
9. It does not integrate with any other services.
   
10. It does not support any text format, but instead is configurable via GUI.
    

CyberArk Secretless Broker

1. CyberArk Secretless Broker is yet another solution that involves secure brokers. It is open-source.
   
2. It forces us to maintain the entire service on our Kubernetes cluster and deploy sidecar agents to generate trust relationships.
   
3. It does not support any external key management service.
   
4. It is free. No costs seem to be incurred.
   
5. It is a common Secrets Engine, meaning that secrets are not stored as code, losing versioning.
   
6. It does not support auditability and reproducibility as there is no versioning.
   
7. It is a service that must be managed separately, making integration with DevOps flows harder.
   
8. It only supports automatic rotations for MySQL and PostgreSQL, meaning that manual rotation is still needed.
   
9. It only integrates with other CyberArk services like CyberArk Conjur.
   
10. It does not support any text format, but instead is configurable via CLI.
    

Usage

Used for managing most of our organizational secrets within the Universe repository.

We use GitLab CI/CD Variables over Sops for:

1. Exporting Cachix authorization tokens as Nix requires it to be available prior to Sops initialization.
   
2. Exporting environment variables required by containers that do not support Sops.