// explicit encryption — keyAltName supported today
await clientEncryption.encrypt(value, {
  keyAltName: "ssn-key",
  algorithm: "Unindexed"
});

// auto encryption — keyAltName NOT supported, must use a UUID
const client = new MongoClient(uri, {
  autoEncryption: {
    encryptedFieldsMap: {
      "mydb.users": {
        fields: [{ path: "ssn", bsonType: "string", keyId: new UUID("a5f3...") }]
      }
    }
  }
});

const client = new MongoClient(uri, {
  autoEncryption: {
    encryptedFieldsMap: {
      "mydb.users": {
        fields: [{ path: "ssn", bsonType: "string", keyAltName: "ssn-key" }]
      }
    }
  }
});