Features

Overview

On this page, you can learn about the security benefits of Queryable Encryption, how it works, and how it compares to other security mechanisms supported by MongoDB. You can also view a fictional scenario that demonstrates the value of Queryable Encryption in securing your data.

Queryable Encryption

Queryable Encryption enables a client application to encrypt data before transporting it over the network using fully randomized encryption, while maintaining queryability. Sensitive data is transparently encrypted and decrypted by the client and only communicated to and from the server in encrypted form.

Unlike Client-Side Field Level Encryption that can use Deterministic Encryption, Queryable Encryption uses fast, searchable encryption schemes based on structured encryption. These schemes produce different encrypted output values even when given the same cleartext input.

How Queryable Encryption Works

The diagram below shows the process and architecture of how Queryable Encryption is used in a customer environment.

In this diagram, the user is able to query on fully randomly encrypted data such as SSN number.

The process and mechanisms that make this possible within Queryable Encryption are as follows:

1. When the application submits the query, MongoDB drivers first analyze the query.

2. The driver recognizes the query is against an encrypted field and requests the encryption keys from the customer-provisioned key provider such as:

   • AWS Key Management Service (AWS KMS)

   • Google Cloud KMS

   • Azure Key Vault

   • Any KMIP-compliant key provider

3. The driver submits the query to the MongoDB server with the encrypted fields rendered as ciphertext.

4. Queryable Encryption implements a fast, searchable scheme that allows the server to process queries on fully encrypted data, without knowing anything about the data. The data and the query itself remain encrypted at all times on the server.

5. The MongoDB server returns the encrypted results of the query to the driver.

6. The query results are decrypted with the keys held by the driver and returned to the client and shown as plaintext.

Queryable Encryption functions with the help of the following data structures. It is critical that these are not modified or deleted, or query results will be incorrect.

• Queryable Encryption adds a __safeContent__ field to documents in any collection where there's a Queryable Encryption encrypted field.

• Queryable Encryption creates two internal metadata collections in the same database as the collection where there's a Queryable Encryption encrypted field. These are named as follows:

  • enxcol_.<collectionName>.esc

  • enxcol_.<collectionName>.ecoc

Queryable Encryption keeps encrypted fields secure in the following scenarios:

• Direct access to encrypted fields by a database superuser

• Access to encrypted fields by reading the server's memory

• Capture of encrypted fields over an insecure network

• Access to on-disk encrypted fields by reading database or backup files

• Frequency analysis attacks by identifying patterns in documents with encrypted fields

While all clients have access to the non-sensitive data fields, only appropriately-configured Queryable Encryption clients are able to run read and write queries using the encrypted data fields.

Other Security Mechanisms

This section describes the following security mechanisms supported by MongoDB and explains their use cases and limitations:

• Role-Based Access Control

• Encryption at Rest

• Transport Encryption (TLS/SSL)

Comparison of Features

To learn more about Client-Side Field Level Encryption, see Client-Side Field Level Encryption Features.

The following table describes potential security threats and how MongoDB encryption features address them. Use these mechanisms together: Role-Based Access Control, Encryption at Rest, Transport Encryption, and In-Use Encryption. Note that you can't use both Client-Side Field Level Encryption and Queryable Encryption in the same collection.

When using Queryable Encryption, equality and range queries offer similar security against attackers with database snapshots. However, an attacker with access to both database snapshots and query information is beyond the scope of Queryable Encryption's security guarantees. This is especially true for range queries, even if only a small number of query transcripts or logs are retrieved. See 6.1: Range Queries in the Persistent Model in the overview whitepaper for details.

Scenario

The following fictional scenario demonstrates the value of Queryable Encryption in securing your application's data, and how Queryable Encryption interacts with the other security mechanism discussed in this guide.

In this scenario, we secure sensitive data on a medical care management system that stores patients' personal information, billing information, and medical records for a fictional company, MedcoMD. None of the patient data is public, and specific data such as their social security number (SSN, a US government-issued ID number), patient ID number, billing information, and medication information are particularly sensitive and subject to privacy compliance. It is important for the company and the patient that the data is kept private and secure.

MedcoMD needs this system to satisfy the following use cases:

• Doctors use the system to access patients' medical records, billing information, and update medications.

• Receptionists use the system to verify patients' identities using their contact information.

• Receptionists can view a patient's billing information, but not their patient ID number.

• Receptionists cannot access a patient's medical records.

MedcoMD is also concerned with the disclosure of sensitive data through any of the following methods:

• Accidental disclosure of data on a receptionist's publicly-viewable screen.

• Direct access to the database by a superuser such as a database administrator.

• Capture of data over an insecure network.

• Access to data by reading the database server's memory.

• Access to data by reading database or backup files.

What can MedcoMD do to balance the functionality and access restrictions of their medical care management system?

Learn More

To view a list of security measures you should implement to protect your MongoDB deployment, see the Security Checklist.

To start using Queryable Encryption, see the Quick Start.