Laravel 11 introduces a new feature to gracefully handle encryption key rotation while ensuring user sessions remain secure. Here's how it works:
APP_PREVIOUS_KEYS Environment Variable
Laravel 11 allows you to define a list of previous encryption keys using the `APP_PREVIOUS_KEYS` environment variable. This variable stores a comma-delimited list of previous keys that Laravel will attempt to use for decryption if the current key fails[1][2].Graceful Decryption Process
When decrypting values, such as session cookies, Laravel first tries the current `APP_KEY`. If decryption fails using the current key (e.g., if the data was encrypted with an older key), Laravel will automatically try the keys listed in `APP_PREVIOUS_KEYS` until it finds a key that successfully decrypts the data[1][2].Automatic Re-encryption
As users interact with the application, Laravel will re-encrypt the data with the new key. This process happens seamlessly in the background, ensuring a smooth transition without data loss or user disruption[1].Session Retention
By maintaining access to previous keys, Laravel allows existing user sessions to continue functioning normally even after the `APP_KEY` is rotated. Users remain logged in without interruption, as Laravel can decrypt the session cookie using the previous keys[1][2].Encrypted Model Attributes
For encrypted model attributes, such as sensitive user data stored in the database, developers can create a migration job to batch-process the re-encryption of existing data with the new key. This ensures that all encrypted data is updated to the latest key over time as users interact with the application[2].In summary, Laravel 11's new key rotation features provide a secure and user-friendly way to rotate encryption keys by allowing the use of previous keys for decryption and automatically re-encrypting data with the new key. This ensures that user sessions remain intact and encrypted data remains accessible during the key rotation process.
Citations:[1] https://securinglaravel.com/in-depth-graceful-encryption-key/
[2] https://www.youtube.com/watch?v=M79PK1ExG4I
[3] https://www.youtube.com/watch?v=0dJMX9RjW9A
[4] https://www.pullrequest.com/blog/hardening-your-laravel-applications-tips-for-secure-session-and-cookie-management/
[5] https://laracasts.com/series/whats-new-in-laravel-11/episodes/12