A post recently appeared on Hive portal (it's a blockchain-based blog portal with rewards for writers) describes encrypting and decrypting files using Yubikey. It covers preparation (hardware key configuration), decryption and encryption using console commands but also it covers integration with Directory Opus 12 or newer and pastes complete script to add encrypt/decrypt with Yubikey command to Opus.
The link is: Encrypting files with YubiKey — Hive