I see random websites that aren't open source saying they are "encrypted, safe", when they obviously aren't! Come on!
i usually assume the worst of sites like this, and i skip right over them..
tesseract, a very popular foss ocr engine, maintains a list of 3rd party gui interfaces:
https://tesseract-ocr.github.io/tessdoc/User-Projects-%E2%80%93-3rdParty.html
this is where i would start if i couldn't just scan and use my naps2.