Methods, systems, and computer programs are presented for secure data encryption in a multi-tenant service platform. One method includes an operation for detecting a write request to write index data to storage. The write request is from a first user from a group of users, and the storage is configured to store index data for the group of users. Further, the method includes operations for authenticating that the first user is approved for access to the storage, and for identifying a first encryption key for the first user, where each user from the group of users has a separate encryption key. Further yet, the method includes encrypting the index data with the first encryption key and storing the encrypted index data in the storage.