Introduction

In today’s fast-paced development world, securing sensitive data such as API keys, database credentials, and other secrets is crucial. Ruby on Rails provides several ways to manage secrets securely, but ensuring they remain safe throughout the application lifecycle requires following best practices.

In this guide, we’ll explore:
✔️ The importance of securing secrets in Rails
✔️ Tools and methods for managing secrets securely
✔️ Best practices for environment-specific secrets
✔️ How to integrate with Rails credentials, dotenv, and Vault
✔️ Practical tips to avoid common mistakes

1. Why Managing Secrets is Critical

Secrets such as API keys, authentication tokens, and database credentials are integral to the functionality of your application. If they are compromised, attackers can:

  • Access sensitive user data
  • Modify your database or environment
  • Cause unauthorized access to third-party services

By handling secrets securely, you minimize the risk of exposing sensitive information.

2. Rails 5+ Credentials and Encrypted Secrets

Rails introduced credentials in version 5.2 to help developers store secrets securely in the application.

Setting Up Rails Credentials

To get started, you can create and edit credentials in an encrypted file that is not stored in version control. Here’s how you do it:

  1. Generate credentials using Rails commands:

    rails credentials:edit

  2. Add your secrets in the config/credentials.yml.enc file. This file is encrypted, and Rails will automatically decrypt it at runtime.

    aws:  
access_key_id: "your-access-key-id"  
secret_access_key: "your-secret-access-key"

  3. Access the credentials using Rails’ Rails.application.credentials:

    Aws::S3::Resource.new(region: 'us-west-1', credentials: Aws::Credentials.new(  
Rails.application.credentials.aws[:access_key_id],  
Rails.application.credentials.aws[:secret_access_key]  
))
Benefits:
  • Encrypted and decrypted automatically
  • Only accessible by the Rails application at runtime
  • The encryption key is stored in the environment, not in the project directory

3. Using dotenv for Local Development Secrets

For local development or when you don’t want to rely on the Rails credentials system, dotenv is a lightweight solution to manage environment variables.

Setup dotenv in Rails

  1. Add the dotenv gem to your Gemfile:

    gem 'dotenv-rails', groups: [:development, :test]

  2. Create a .env file in your application’s root directory:

    AWS_ACCESS_KEY_ID=your-access-key-id  
AWS_SECRET_ACCESS_KEY=your-secret-access-key

  3. Access the secrets in your code:

    Aws::S3::Resource.new(region: 'us-west-1', credentials: Aws::Credentials.new(  
ENV['AWS_ACCESS_KEY_ID'],  
ENV['AWS_SECRET_ACCESS_KEY']  
))
Best Practices with dotenv:
  • Never commit .env files to version control
  • Use environment-specific files like .env.production and .env.development
  • Use dotenv for development, but move to Rails credentials or more secure systems for production

4. Leveraging HashiCorp Vault for Enterprise-Level Secrets Management

For enterprise applications or when managing highly sensitive secrets, using a dedicated secrets management service like HashiCorp Vault is essential.

Why HashiCorp Vault?

Vault is designed to provide a centralized, auditable, and secure way to manage secrets, tokens, certificates, and encryption keys. It provides:

  • Dynamic secrets generation (e.g., database credentials)
  • Fine-grained access control
  • Encryption as a service
Integrating Vault with Rails

  1. Install the vault-ruby gem in your Gemfile:

    gem 'vault'

  2. Configure Vault:

    Vault.address = "https://vault.example.com"
Vault.token = "your-vault-token"

  3. Fetch secrets from Vault:

    secret = Vault.logical.read("secret/data/myapp/aws")  
aws_access_key = secret.data[:data][:access_key_id]  
aws_secret_key = secret.data[:data][:secret_access_key]
Best Practices with Vault:
  • Use role-based access to define who can access which secrets
  • Integrate with Audit devices for detailed logging
  • Rotate secrets periodically to minimize exposure

5. Best Practices for Secret Management

Now that we’ve covered the tools and techniques, let’s dive into some best practices to keep your secrets safe:

1. Rotate Secrets Regularly

Regularly rotate API keys, database credentials, and tokens to reduce the risk of prolonged exposure in case they’re compromised. Automated rotation is a good strategy in large-scale applications.

2. Keep Secrets Out of Version Control

Make sure to exclude sensitive files like .env or config/credentials.yml.enc from your version control system by adding them to .gitignore.

3. Use Least Privilege Principle

Limit access to secrets only to those who absolutely need it. In production, avoid giving full access to all secrets—especially in shared environments.

4. Audit Access to Secrets

Set up logging and auditing mechanisms to track when and how secrets are accessed, especially in production environments.

5. Use Multi-Factor Authentication (MFA)

Implement MFA for services that store or access sensitive data to add an extra layer of protection.

Conclusion

Managing secrets securely is a fundamental part of building secure Ruby on Rails applications. By following the best practices and utilizing tools such as Rails credentials, dotenv, and Vault, you can minimize the risk of exposing sensitive information.

✔️ Use Rails credentials for encrypted, environment-specific secrets.
✔️ Leverage dotenv for local development, while avoiding committing sensitive data to version control.
✔️ For enterprise-level applications, integrate Vault for centralized secrets management.

By securing your secrets, you not only protect your app but also ensure that your users’ data remains safe. Start applying these techniques today to fortify your Rails applications.