Encrypting Kafka Fields Tagged in Schema Registry Using Kafka Connect

Field-level encryption in Apache Kafka is crucial for securing sensitive data such as Personally Identifiable Information (PII) or financial details. By tagging fields in an Avro schema managed by the Confluent Schema Registry, you can automate encryption using Kafka Connect. This blog explores how to achieve this with different approaches, focusing on implementation details, examples, and trade-offs.

Why Encrypt Kafka Fields?

Encryption ensures data confidentiality and compliance with regulations like GDPR, CCPA, or HIPAA. Kafka Connect pipelines often process sensitive data; encrypting fields tagged in the Schema Registry ensures secure transmission and storage.

Approaches to Encrypt Kafka Fields

1. Custom Single Message Transforms (SMTs)

Description
SMTs modify Kafka Connect records as they pass through a connector pipeline. A custom SMT can encrypt fields tagged in the Avro schema dynamically.

Implementation Steps

• Step 1: Extend the Transformation interface in Kafka Connect.
• Step 2: Retrieve Avro schema metadata from Schema Registry.
• Step 3: Identify tagged fields (e.g., fields with a tags: ["PII"] annotation).
• Step 4: Encrypt tagged fields using an external key…