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Client-Side Field Level Encryption: Use a KMS to Store the Master Key

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This guide shows you how to migrate from using Client-Side Field Level Encryption (CSFLE) with a locally-managed master key to one that uses a remote Key Management Service (KMS) and is intended for full-stack developers.

Currently, MongoDB drivers support the following Key Management Providers:

Once you complete the steps in this guide, you should have:

  • a master key hosted by one of the supported remote Key Management Services
  • a working client application that encrypts and decrypts the data encryption key using the KMS master key

This guide requires that you completed the following:

  • created a CSFLE-enabled client using our CSFLE guide
  • decrypted any data encrypted while using a local KMS master key

Choosing a remote KMS for master key management has the following advantages over using your local filesystem to host the master key:

  • Secure storage of the key with access auditing
  • Reduced risk of access permission issues
  • Availability and distribution of the key to remote clients
  • Automated key backup and recovery
  • Centralized encryption key lifecycle management

Additionally, MongoDB transmits the data encryption keys to the KMS provider for encryption and decryption, ensuring the Customer Master Key (CMK) is never exposed to the client.

Decrypt all encrypted field data first

Before you switch from a locally-managed master key to a remote KMS, you must decrypt all documents containing field-encrypted data if you want to keep it. Your existing data encryption keys can only be decrypted with the original locally-managed master key and not the CMK that the KMS generates.

Failure to decrypt all data at this stage may cause permanent and unrecoverable data loss.

The following steps explain the setup and updates necessary to move from a local key provider to a KMS provider. Select the tab that corresponds to your provider:

For more information on client-side field level encryption in MongoDB, check out the reference documentation in the MongoDB server manual:

←  Client-Side Field Level Encryption Guide
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