Add HMAC-SHA256 data integrity
Version 0.3.0 introduces another breaking change by prepending the IV and cipher data with a HMAC-SHA256 hashing the IV and encrypted data using the same key used for the AES-CFB encryption. The HMAC is used to validate the message on decryption. Performance impact could not be measured in the benchmark tests and we gain better data integrity.
Full Changelog: v0.2.0...v0.3.0