CertKeyU

In daily work and life, we often use keys to connect to servers, github repositories, etc. Putting the private key directly in a portable USB flash drive is easy to delete by mistake and is unsafe. Storing the key in a single USB flash drive is too wasteful, so we made a small storage device. The idea was because I had some idle EEPROM on hand, which was just big enough to store the key pair. All that was left was to find a driver IC. However, ICs for this kind of application are still very rare. By chance, I browsed Qinheng’s official website and saw the CH331. This IC was a surprise. The final result was this project.

*  Note: This project uses the file mode of CH331. The CH331A model currently promoted by Qinheng does not support the file mode. You need to purchase the CH331G model through channels (also known as CH331T. The engineer who consulted Qinheng said it is a customized model from a customer)**