We've been looking at adding Google Authenticator to a CFML/Lucee/Railo/ACF project for a while as a proof of concpept and luckily there was some work done 4 years ago at marcins/cf-google-authenticator.
Through our own use of the project I've forked and updated the code which has some small adjustments which you can find at andyj/cf-google-authenticator
CHANGES
- I've removed the native CF solution in favour of the Apache Commons Codec to implement Base32 encoding/decoding
- Added new function getOTPQRURL() which return the a QR code URL you can put straight in to an image tag