How to encrypt a Class property using Mongodb CSFLE in dot net core

Question

I am trying to use Mongodb Client side field level encryption (CSFLE) with Dot net core (v5.0).

I have it working using the Json Schema map as per docs, which uses BSONDocument types and I can define each field to encrypt (have followed this guide https://www.mongodb.com/developer/how-to/client-side-field-level-encryption-mongodb-csharp/)

I now need to apply this to individual properties on my C# Class models. Can I use an annotation or somehow tell MongoDb Driver to serialize my class property to the binary type required in the BsonDocument schema?

This works:

  var schemaMap = $@"{{
                properties: {{
                    SSN: {{
                        encrypt: {{
                            keyId: [{{
                                '$binary' : {{
                                    'base64' : '{base64DataKeyId}',
                                    'subType' : '04'
                                }}
                            }}],
                        bsonType: 'string',
                        algorithm: 'AEAD_AES_256_CBC_HMAC_SHA_512-Deterministic'
                        }}
                    }}
                }},
                'bsonType': 'object'
            }}";

 var autoEncryptionSettings = new AutoEncryptionOptions(
                keyVaultNamespace,
                kmsProviders,
                schemaMap: new Dictionary<string, BsonDocument>()
                {
                    { collectionNamespace.ToString(), BsonDocument.Parse(schemaMap) }
                });

I need to somehow apply this to a C# class model like this:

 public class TestModel
        {
            [MongoEncrypted?]
            public string SSN { get; set; }
        }

I use a basic repository pattern, and currently pass my Class models in to the Mongo driver like this

 _mongoCollection = _mongoContext.GetCollection<TEntity>(collectionName);

How do I tell the Mongodb Driver to apply the Json Schema to my existing class properties? Is this possible?

Thank you.

Answer 1

no, it's not possible, json schema should be provided at the moment when you create a mongo client