{
  "db.coll": {
    "bsonType": "object",
    "properties": {
      "encrypted_placeholder": {
        "encrypt": {
          "keyId": "/placeholder",
          "bsonType": "string",
          "algorithm": "AEAD_AES_256_CBC_HMAC_SHA_512-Random"
        }
      }
    }
  }
}