Client Authentication: Secure Key Management

TL;DR

Stop storing your client authentication key directly in your code! This guide shows you how to use environment variables and a secure configuration file to manage your key safely. We’ll cover reading the key from an environment variable, using a config file, and basic security considerations.

Steps

1. Understand the Problem: Hardcoding keys is bad because:
   • If your code gets shared (even accidentally), the key is exposed.
   • Changing the key requires modifying and redeploying your code everywhere.
   • It’s a security risk!
2. Use Environment Variables: Environment variables store configuration information outside of your code.
   • Set an environment variable (e.g., CLIENT_API_KEY) on your server or development machine. The exact method depends on your operating system and hosting provider.
   • In your code, read the key from this variable. Here’s an example in Python:

     import os
     client_api_key = os.environ.get('CLIENT_API_KEY')
     if client_api_key is None:
         print("Error: CLIENT_API_KEY environment variable not set!")
         exit(1)
     # Now you can use client_api_key

3. Use a Configuration File (Recommended): A config file is more organised than many environment variables, especially for complex setups.
   • Create a configuration file (e.g., config.ini or config.json). Example using INI format:

     [API]
     client_api_key = your_secret_api_key
     

   • Load the configuration file in your code.

     import configparser
     config = configparser.ConfigParser()
     config.read('config.ini')
     client_api_key = config['API']['client_api_key']

4. Security Considerations:
   • Never commit your configuration file to version control (e.g., Git)! Add it to your .gitignore file.

     config.ini
     

   • Restrict access to the configuration file on your server. Only the user running your application should be able to read it (permissions: 600).
   • Consider using a secrets management service (e.g., HashiCorp Vault, AWS Secrets Manager) for production environments. These services provide more advanced security features like encryption and access control.
5. Testing:
   • Create separate configuration files or environment variables for development and testing to avoid using your real API key in non-production environments.
   • Ensure your tests read the correct keys based on the current environment.