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Create an Encryption Schema

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.

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.

You can configure encryption for each field in the fields array of your encryptedFieldsObject. The following table describes the available subfields:

Field
Type
Description

path

String

Required. The dot-notation path to the field to encrypt, such as "patientInfo.ssn". You can specify any field except the _id field.

bsonType

String

Required. The BSON type of the field to encrypt. For a complete list of supported types, see Supported and Unsupported BSON Types.

keyId

UUID

Optional. The UUID of the DEK to use for encrypting this field. The UUID is a BSON binary data element of subtype 4.

Key IDs must be unique. Specifying a keyId that is already in use returns an error.

If omitted, you can use the createEncryptedCollection() helper method to create keys automatically.

queries

Object

Optional. Enables querying on this encrypted field. If omitted, the field is encrypted but not queryable.

To learn more about query options, see Configure Encrypted Fields for Optimal Search and Storage.

1

Include an encryptedFieldsObject with a nested fields array:

const encryptedFieldsObject = {
fields: []
}
2
  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

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

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

    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
    }
    }

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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