Create an Encryption Schema

Queryable Encryption prefix, suffix, and substring queries are available in public preview in MongoDB 8.2. Do not enable these query types in production. Public preview functionality will be incompatible with the GA feature, and you will have to drop any collections that enable these queries.

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

Create the encryption schema.

Include an encryptedFieldsObject with a nested fields array:

const encryptedFieldsObject = {
   fields: []
}

Specify fields to encrypt.

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.

Optionally, set a keyId field with the DEK ID.
Important
Key IDs must be unique, otherwise the server returns an error.
By configuring AutoEncryptionSettings on the client, you can use the createEncryptedCollection helper method to create keys automatically.
```
{
   path: "myDocumentField",
   bsonType: "int",
   keyId: "<unique data encryption key>"
}
```

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" }
}

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.

Add the queries object and set queryType to "range":
```
{
   path: "myDocumentRangeField",
   bsonType: "int",
   queries: { queryType: "range" }
}
```

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
   }
}

Enable prefix, suffix, or substring queries on desired fields.

These query types are for string fields only. You can enable both prefixPreview and suffixPreview on the same field, but can't enable either if using substringPreview.

Warning

Prefix, Suffix, and Substring Queries are in Public Preview

prefixPreview queries enable the $encStrStartsWith and $encStrNormalizedEq aggregation expressions.
suffixPreview queries enable the $encStrEndsWith and $encStrNormalizedEq aggregation expressions.
substringPreview queries enable the $encStrContains and $encStrNormalizedEq aggregation expressions.

Add the queries object and set queryType to "prefixPreview", "suffixPreview", or "substringPreview":
```
{
   path: "myDocumentStringField",
   bsonType: "string",
   queries: { queryType: "substringPreview" }
}
```

Set the following fields.

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

Field	Type	Description
`strMaxLength`	integer	`substringPreview` queries only. The maximum allowed length for a substring-indexed field.
`strMinQueryLength`	integer	The minimum allowed prefix/suffix/substring length to query.
`strMaxQueryLength`	integer	The maximum allowed prefix/suffix/substring length to query. IMPORTANT: This setting strongly impacts query performance. Limit it whenever possible.
`caseSensitive`	Boolean	Optional. Whether queries are case-sensitive. Defaults to `true`.
`diacriticSensitive`	Boolean	Optional. Whether queries are diacritic-sensitive. Defaults to `true`.

{
   path: "myDocumentStringField",
   bsonType: "string",
   queries: {
      "queryType": "substringPreview",
      "strMaxLength": 30,
      "strMinQueryLength": 1,
      "strMaxQueryLength": 20,
      "caseSensitive": false
   }
}

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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