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Fundamentals

Create an Encryption Schema

On this page

  • About this Task
  • Before you Begin
  • Steps
  • Create a JSON encryption schema document.
  • Specify fields to encrypt.
  • Enable equality queries on desired fields.
  • Enable range queries on desired fields.
  • Example

About this Task

To make encrypted fields queryable, create an encryption schema. This schema defines which fields are queryable, and which query types are permitted. For more information, see Encrypted Fields and Enabled Queries.

Important

Queryable Encryption supports equality and range queries. You can configure a field for only one query type.

Before you Begin

When you make encrypted fields queryable, consider performance and security. For details on how each configuration option affects these, see Configure Encrypted Fields for Optimal Search and Storage.

Steps

1

Create a JSON encryption schema document.

Include an encryptedFieldsObject with a nested fields array:

const encryptedFieldsObject = {
   fields: []
}
2

Specify fields to encrypt.

  1. Add the path and bsonType strings to a document within the fields array:

    const encryptedFieldsObject = {
       fields: [
          {
             path: "myDocumentField",
             bsonType: "int"
          }
       ]
    }

    Important

    You can specify any field for encryption except the _id field.

  2. If you are using explicit encryption, add a keyId field with the DEK ID:

    {
       path: "myDocumentField",
       bsonType: "int",
       keyId: "<unique data encryption key>"
    }

    Tip

    With Automatic Encryption, MongoDB creates encryption keys for each field. You configure AutoEncryptionSettings on the client, then use the createEncryptedCollection helper method to create your collections.

3

Enable equality queries on desired fields.

This enables querying with the $eq, $ne, $in, and $nin operators.

Add the queries object and set queryType to "equality":

{
   path: "myDocumentField",
   bsonType: "int",
   queries: { queryType: "equality" }
}
4

Enable range queries on desired fields.

This enables querying with the $lt, $lte, $gt, and $gte operators.

For details on how the following options affect security and performance, see Configure Encrypted Fields for Optimal Search and Storage.

  1. Add the queries object and set queryType to "range":

    {
       path: "myDocumentRangeField",
       bsonType: "int",
       queries: { queryType: "range" }
    }

  2. Set the following fields:

    Field
    Type
    Description

    min and max

    Same as field bsonType

    Required if bsonType is decimal or double. Optional but highly recommended if it is int, long, or date. Defaults to the minimum and maximum values of the bsonType.

    When possible, specifying bounds on a query improves performance. If querying values outside of these inclusive bounds, MongoDB returns an error.

    {
       path: "myDocumentRangeField",
       bsonType: "int",
       queries: { queryType: "range",
                  min: 0,
                  max: 1200
       }
    }

Example

This example shows how to create an encryption schema for hospital data.

Consider the following document that contains personally identifiable information (PII), credit card information, and sensitive medical information:

{
   "firstName": "Jon",
   "lastName": "Snow",
   "patientId": 12345187,
   "address": "123 Cherry Ave",
   "medications": [
      "Adderall",
      "Lipitor"
   ],
   "patientInfo": {
      "ssn": "921-12-1234",
      "billing": {
            "type": "visa",
            "number": "1234-1234-1234-1234"
      }
   }
}

To ensure the PII and sensitive medical information stays secure, this encryption schema adds the relevant fields:

const encryptedFieldsObject = {
   fields: [
      {
         path: "patientId",
         bsonType: "int"
      },
      {
         path: "patientInfo.ssn",
         bsonType: "string"
      },
      {
         path: "medications",
         bsonType: "array"
      },
      {
         path: "patientInfo.billing",
         bsonType: "object"
      }
   ]
}

Adding the queries property makes the patientId and patientInfo.ssn fields queryable. This example enables equality queries:

const encryptedFieldsObject = {
   fields: [
      {
         path: "patientId",
         bsonType: "int",
         queries: { queryType: "equality" }
      },
      {
         path: "patientInfo.ssn",
         bsonType: "string",
         queries: { queryType: "equality" }
      },
      {
         path: "medications",
         bsonType: "array"
      },
      {
         path: "patientInfo.billing",
         bsonType: "object"
      },
   ]
}

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